JP2008223434A - Construction method for underground structure and underground structure constructed by the construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily constructing an underground structure in which a pipe or the like is buried, used in constructing a well in a short time while preventing boiling. <P>SOLUTION: A well drilling guide 1 is erected in a soil cement column wall 2 in the unconsolidated state. A water supply machine 8 installed on the ground is connected to a force-feed pipe 9, and the water supply machine 8 is operated to force water into the force-feed pipe 9. Water is injected until the water in the well drilling guide pipe 6 reaches a pressure value P1. Fluid such as sediment and ground water is prevented from flowing into the well drilling guide pipe 6 by pressure (the pressure value P1) of water stored in the well drilling guide pipe 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a construction method for constructing an underground structure in which a pipe is embedded.

  Conventionally, when excavating the ground by the open-cut method, a well for draining water is constructed and groundwater is pumped to lower the groundwater level. Particularly in recent years, a method of providing a well for draining water in an underground structure such as soil cement or RC has been used.

  For example, in Patent Document 1, a steel pipe with a lid attached to the tip is inserted into a retaining wall made of soil cement, and the ground from the lower end of the steel pipe to a predetermined depth is drilled using this steel pipe as a guide. A method for constructing a drain well is disclosed. In this method, a steel pipe whose end is capped with a plastic lid is inserted to the lower end of the unsolidified soil cement so that the soil cement does not enter the interior, and then the lid is crushed with a drilling machine and the steel pipe A well for draining is constructed by drilling a hole from the lower end to a predetermined depth.

  Patent Document 2 discloses a method of constructing a plurality of drain wells and constructing earth retaining walls made of soil cement between these wells. In this method, first, steel pipes with strainers are inserted at the locations where the retaining walls are to be constructed, and a plurality of wells for draining are constructed by filling soil cement around these steel pipes with strainers. A soil retaining wall is constructed by drilling the ground between the wells and filling with soil cement to connect the both ends of the retaining wall to the well. Is.

Further, Patent Document 3 discloses a method of constructing a continuous underground wall and constructing a drain well so as to penetrate the continuous underground wall. In this method, first, the ground is drilled, and the drilled portion is filled with cement milk or the like to construct a continuous underground wall. A well for draining is constructed by drilling a hole reaching the depth.
JP 2001-115458 A JP-A-11-81301 JP 2002-138461 A

  However, in the method described in Patent Document 1, since the soil cement has high viscosity and low fluidity, a large load is required to build a steel pipe with a capped tip into the soil cement. The steel pipe must be thickened to withstand. Moreover, in order to insert this steel pipe, a large pile driver is required. Therefore, there has been a problem that material costs and capital investment costs become high.

  In addition, in the method described in Patent Document 2, when a retaining wall is constructed, since a well has already been constructed, work must be performed while paying attention not to damage the well, resulting in poor work efficiency. Become. Further, since a portion of the soil cement of the well is shaved to connect the well and the retaining wall, there is a problem that this connecting portion may become a sliding surface due to a water channel or shearing force. Therefore, it is necessary to implement measures such as water stop measures at the connecting portion or insert dowels so as not to be a sliding surface, which causes a problem that the construction period becomes long.

  Moreover, in the method of patent document 3, when drilling the hole which penetrates a continuous underground wall, a hole may be bent and a hole may penetrate to the side surface of a continuous underground wall. there were. In addition, it takes a long time to drill the inside of the hardened continuous underground wall by a general boring method, so that there is a problem that the construction process of the well becomes long. Furthermore, since the strength of the continuous underground wall increases when the ground condition is poor or when the root cutting depth is deep, there is a problem that the time required for drilling is further increased.

  Therefore, the present invention has been made in view of the conventional problems as described above, and it is easy to quickly embed an underground structure such as a pipe used for constructing a well while preventing boiling. It aims to provide a way to build.

  In order to achieve the above object, the underground construction method according to the present invention is a construction method of an underground structure in which a pipe is embedded, and a hardening material that hardens over time and constitutes the underground structure. An installation process in the ground in a fluidized state, an insertion process in which a cylindrical tube having both ends open is inserted into the hardened material in a fluidized state, and a fluid such as earth and sand or groundwater enters the tube from the lower end of the tube. And an inflow prevention step for preventing inflow. (First invention).

  According to the construction method of the underground structure according to the present invention, an installation process of providing a hardened material that hardens over time in the ground in a fluidized state, and a cylindrical tube having both ends opened into the fluidized hardened material are inserted. And the insertion step to be performed, the pipe can be installed in the underground structure. In addition, since the inflow prevention process prevents the inflow of fluid such as ground water or earth and sand from the lower end of the pipe into the pipe, it is possible to prevent boiling.

According to a second aspect of the present invention, in the first aspect, in the inflow prevention step, the fluid is prevented from flowing into the tube by its own weight while replacing the hardening material present in the tube with the liquid. It is characterized by that.
According to the construction method of the underground structure according to the present invention, fluid such as water and muddy water is prevented from flowing into the pipe due to its own weight, so that fluid such as groundwater and earth and sand does not flow into the pipe from the lower end of the pipe. .

According to a third invention, in the first invention, in the inflow prevention step, the lower end of the pipe is closed by a closing means to prevent the fluid from flowing into the pipe.
According to the underground construction method according to the present invention, the lower end of the pipe is closed by the closing means, so that fluids such as groundwater and earth and sand do not flow into the pipe from the lower end of the pipe.

According to a fourth aspect of the present invention, in the first aspect, in the flow prevention step, the curing material is left at a lower end portion in the pipe by a predetermined amount, and the fluid is kept by its own weight. Inflow into the pipe is prevented.
According to the underground construction method according to the present invention, since a predetermined amount of the hardener remaining in the pipe is left, fluid such as groundwater and earth and sand does not flow into the pipe from the lower end of the pipe.

According to a fifth invention, in any one of the first to third inventions, one end of the pipe is connected to a water supply port provided in a lower portion of the pipe, and a liquid such as water or muddy water is fed into the pipe. It is characterized in that a pressure feeding pipe for connecting is connected.
According to the underground construction method according to the present invention, since the pressure feeding pipe is connected to the water supply port provided at the lower part of the pipe, the liquid can be supplied into the pipe through the pressure feeding pipe.

In a sixth aspect based on the fifth aspect, the water supply port is provided with a water stop means that opens when the liquid in the pressure feeding pipe becomes higher than a predetermined pressure and can supply the liquid into the pipe. It is characterized by being.
According to the construction method of the underground structure according to the present invention, by providing a water stop means at the water inlet of the pipe, it is possible to prevent inflow of cement milk or the like into the pressure feeding pipe when the pipe is built in the underground structure. Is possible.

According to a seventh invention, in the sixth invention, the water stop means is a check valve or a water stop cock provided from the inside of the pipe.
According to the construction method of the underground structure according to the present invention, the check valve and the stop cock are excellent in the market.

In an eighth aspect based on the third aspect, the closing means is disposed along a cover for closing the lower end surface of the tube and an outer peripheral surface of the tube, and one end is connected to the cover. The wire rope is connected to the other end of the wire rope, and is constituted by a winder for winding the wire rope.
According to the underground construction method according to the present invention, it is possible to easily close the lower end surface of the pipe by winding the wire rope after the pipe is inserted into a predetermined position.

In a ninth aspect based on the eighth aspect, the lid has a disk shape, and includes protrusions at both ends in the diameter direction, and the tube engages the protrusion at the one end side. The lid is rotatably attached to the tube by engaging the protrusion of the lid with the notch of the tube.
According to the construction method of the underground structure according to the present invention, the lid can be easily attached to the pipe by engaging the protrusion of the lid with the notch of the pipe.
Further, since the lid rotates in the tube around the protrusion, the lower end surface of the tube can be opened and closed. Therefore, the pipe can be built in a predetermined position such as the ground or retaining wall with both ends opened.

According to a tenth aspect of the present invention, in any one of the first to ninth aspects, the well is constructed in the underground structure by excavating a hole to a predetermined depth inside the pipe using the pipe as a guide. Features.
According to the underground construction method according to the present invention, since the pipe is installed in the underground structure, it is possible to prevent collapse of the hole wall during drilling. Therefore, it becomes possible to confirm the groundwater level reliably for a long period of time.

According to an eleventh aspect, in the tenth aspect, the pipe is embedded so that a lower end portion of the pipe protrudes below a lower end of the underground structure.
According to the underground construction method according to the present invention, when a well is constructed by drilling a hole in the pipe, the lower end of the pipe is separated from the lower end of the underground structure. Since fluids such as groundwater and earth and sand around the lower end do not flow into the pipe, the ground around the underground structure is not loosened.

A twelfth aspect of the invention is characterized in that, in any one of the first to eleventh aspects, the tube is a core material of the underground structure.
According to the underground construction method according to the present invention, since the pipe is used as a core material, the strength of the underground structure can be improved.

A thirteenth invention is characterized in that, in any one of the first, second, and fourth inventions, the hardener contains either soil cement or concrete.
According to the construction method for underground structure according to the present invention, soil cement and concrete have excellent market availability.

  In a fourteenth aspect based on any one of the first to thirteenth aspects, the underground structure is any one of a wall, a pile, and a wall pile.

  The underground structure according to the fifteenth aspect of the present invention is constructed by the construction method according to any one of the first to fourteenth aspects of the invention.

  By using the underground construction method according to the present invention, it is possible to easily construct a buried underground structure such as a pipe used for constructing a well in a short time while preventing boiling. .

  Hereinafter, preferred embodiments of the underground construction method of the present invention will be described in detail with reference to the drawings. In the following embodiments, a method of installing a well drilling guide for a tubular pipe in a soil cement column wall that is an underground structure will be described as an example. It can also be applied to structures. Here, the installation of a well drilling guide for a pipe according to the present invention means that a well drilling guide is inserted into a soil cement column wall or the like, and water or mud flows from the lower end of the well drilling guide. This refers to the process until the large inflow is prevented.

  FIGS. 1 and 2 are a perspective sectional view and a longitudinal sectional view, respectively, showing a state where the well drilling guide 1 according to the first embodiment of the present invention is installed in the soil cement column wall 2.

  As shown in FIG.1 and FIG.2, the soil cement column wall 2 is installed so that the circumference | surroundings of the excavation planned location 5 excavated by the open-cut method in order to construct | assemble an underground structure etc. may be surrounded. The lower end of the soil cement column wall 2 is installed so as to penetrate the clay layer 3 of the impermeable layer that forms the underground structure and reach the upper part of the sand layer 4 of the pressurized aquifer.

  In addition, in this embodiment, although the ground demonstrates the case where it consists of the clay layer 3 and the sand layer 4, it is not limited to this, For example, the ground which consists of all the sand layers 4 may be sufficient.

  When excavating the planned excavation site 5 surrounded by the soil cement column wall 2, a well for draining water is used to drain the pressured groundwater in the sand layer 4 in order to lower the level of the pressured groundwater. Built. A well drilling guide 1 is installed in the soil cement column wall 2 as a guide for guiding the drilling direction when drilling the drain well. The well drilling guide 1 is installed so as to penetrate through the soil cement column wall 2 in the depth direction.

  FIG. 3 is a cross-sectional view of the well drilling guide 1 according to the present embodiment. As shown in FIG. 3, the well drilling guide 1 includes a cylindrical well drilling guide tube 6 and a pressure feeding tube for feeding liquid such as water and muddy water into the well drilling guide tube 6. 9.

  The well drilling guide tube 6 is a hollow tube that is open at both ends, and is installed so that the longitudinal direction is substantially the same as the drilling direction of the drain well.

  The lower end of the pumping pipe 9 is connected to a water supply port 7 provided at the lower part of the well drilling guide pipe 6, and the upper end is connected to a water supply 8 such as a water supply pump. The pressure feed pipe 9 is joined by welding along the outer peripheral surface of the well drilling guide pipe 6, and a pressure sensor 10 for measuring water pressure is provided inside the lower end (water supply port 7) side. It has been. The measured value by the pressure sensor 10 is transmitted to the ground and can be monitored by a ground monitor or the like (not shown). The pressure of the water supplied into the pressure feeding pipe 9 is adjusted by the water feeder 8 while monitoring the measurement value by the pressure sensor 10. In this embodiment, the well drilling guide pipe 6 and the pressure feed pipe 9 are round steel pipes. Note that the well drilling guide pipe 6 and the pressure feed pipe 9 are not limited to steel pipes, and may have any strength that does not break when built into the soil cement column wall 2, for example, strengthened A cylindrical tube made of plastic or the like may be used.

  The water supply port 7 of the well drilling guide pipe 6 is opened when the pressure of the water in the pumping pipe 9 reaches a predetermined value or more, so that the water in the pumping pipe 9 can be supplied into the well drilling guide pipe 6. The water stop means 11 is connected. In the present embodiment, a water stop cock made of rubber or plastic is used as the water stop means 11. The water stop cock has a convex shape, and its protrusion is mounted so as to close the water supply port 7 from the inside of the well drilling guide pipe 6. When water is injected into the pressure feed pipe 9, the water stop cock stops. The faucet drops into the well drilling guide pipe 6 due to water pressure, the pressure feed pipe 9 and the well drilling guide pipe 6 communicate with each other, and water is supplied into the well drilling guide pipe 6.

  In addition, the water stop means 11 is not limited to a water stop cock, You may use a check valve.

Next, a method for installing the well drilling guide 1 in the soil cement column wall 2 will be described.
4-10 is a figure which shows the installation procedure of the guide 1 for well drilling which concerns on this embodiment.

  As shown in FIG. 4, the well drilling guide 1 is built into the fluidized soil cement column wall 2 by a crane 12 installed on the ground.

  As shown in FIG. 5, the well drilling guide 1 is built until the lower end portion of the well drilling guide pipe 6 penetrates the soil cement column wall 2 and reaches the sand layer 4. Since the water supply port 7 is capped with a water stop cock, the soil cement does not flow into the pressure feeding pipe 9 when the well drilling guide pipe 6 is installed.

As shown in FIG. 6, when the soil cement starts to solidify, the water feeder 8 such as a water pump installed on the ground is operated to press-fit water into the pressure feed pipe 9. When water is press-fitted into the pressure feed pipe 9, the stop cock of the water supply port 7 drops into the well drilling guide pipe 6 due to the water injection pressure, and the water falls on the lower end of the well drilling guide pipe 6. While pushing up the soil cement, it flows in and stores. In this state, water is injected until the water in the well drilling guide pipe 6 reaches a pressure value P1 (described later).
The soil cement in the well drilling guide pipe 6 is moved upward by the pressure of the water stored in the well drilling guide pipe 6 (pressure value P1) and discharged to the outside.

  Below, the calculation method of the pressure value P1 of the water required in order to move the soil cement in the guide pipe 6 for well drilling upwards is demonstrated.

As shown in FIG. 7, the load Fw acting on the lower end surface of the soil cement of the water stored in the lower end portion of the well drilling guide tube 6 is expressed by equation (1).
Fw = P × π × r ² (1)
Here, P: water pressure, r: radius of the inner peripheral surface of the well drilling guide pipe 6.

Further, the weight Fs of the soil cement in the well drilling guide pipe 6 is expressed by the equation (2).
Fs = γt × Z × π × r ² (2)
Here, γt: soil cement unit volume weight, Z: soil cement covering thickness.

Further, the frictional force Fm generated when the soil cement moves upward in the well drilling guide pipe 6 is expressed by equation (3).
Fm = 2 × π × r × Z × f (3)
Here, f is the peripheral surface frictional force of the well drilled steel pipe.

In order to move the soil cement in the well drilling guide pipe 6 upward and discharge it to the outside, it is necessary to satisfy the following equation (4).
Fw> Fs + Fm (4)
Therefore, when the formulas (1) to (3) are substituted into the formula (4), the formula (5) is obtained.
P × π × r ² > γt × Z × π × r ² + 2 × π × r × Z × f (5)
If this equation (5) is modified, equation (6) is obtained.
P> γt × Z + Z × f / r (6)

  That is, as shown in the equation (6), in order to move the soil cement in the well drilling guide pipe 6 upward and discharge it to the outside, the pressure of the water stored in the well drilling guide pipe 6 P must be larger than the sum of the pressure (= γt × Z) due to the weight of the soil cement and the frictional force (= Z × f / r) of the soil cement.

Further, in order to move the soil cement upward and to prevent boiling, it is necessary to satisfy the following expression (7).
P> Wp (7)
Here, Wp is the pressure of the groundwater under pressure, and a value measured in advance by a geological survey or the like is used.

  Thus, the pressure P of the water stored in the well drilling guide pipe 6 needs to satisfy the formula (6) and the formula (7). Therefore, the water pressure in the well drilling guide pipe 6 is set to a predetermined pressure higher than the sum of the pressure due to the weight of the soil cement (= γt × Z) and the frictional force of the soil cement (= Z × f / r). The pressure value P1 is adjusted to a larger value. Thereby, the soil cement moves upward and is discharged to the ground sequentially from the upper part of the soil cement. At this time, as shown in FIG. 8, water having the same volume as the discharged soil cement is injected into the well drilling guide tube 6. In addition, the said predetermined pressure is suitably determined according to field conditions, for example, the pressure maintenance performance of the water feeder 8, etc.

  When soil cement is discharged sequentially, the weight of the soil cement gradually decreases. Therefore, if the pressure value P1 is kept constant, the friction force of the soil cement is added to the pressure value P1 and the pressure due to the weight of the soil cement. The pressure difference from the value gradually increases, and soil cement may jump out to the ground. Therefore, the volume of the soil cement remaining in the well drilling guide pipe 6 (here, the thickness Z) is estimated from the volume of the discharged soil cement, and the pressure value P1 is gradually decreased to reduce the soil cement. The soil cement is discharged while preventing popping out. However, the pressure value P1 should not be smaller than the water pressure Wp of the groundwater to be pressurized.

  And finally, as shown in FIG. 9, all the soil cement in the well drilling guide tube 6 is discharged | emitted, and it will be in the state with which the well drilling guide tube 6 was filled with water.

  Finally, as shown in FIG. 10, a rod 13 having a drilling bit is inserted into the well drilling guide pipe 6, and the well drilling guide pipe 6 is used as a guide for drilling to drill the holes up to the sand layer 4. Drill holes and build wells.

  According to the method for installing the well drilling guide 1 in the present embodiment described above, water is injected into the lower end portion of the well drilling guide pipe 6 and the inflow of the pressurized groundwater is caused by the pressure of the water. While holding down, the soil cement existing in the well drilling guide pipe 6 is pushed upward and discharged to the outside, and the inside of the well drilling guide pipe 6 is replaced with this water. Groundwater and earth and sand do not flow into the well drilling guide pipe 6 from the lower end of the drilling guide pipe 6. Therefore, boiling can be prevented.

  Further, since the soil cement is moved upward by the pressure of the water press-fitted into the lower end of the well drilling guide pipe 6 and discharged, the soil cement can be discharged without using a crusher such as an earth auger. Therefore, since no noise is generated, it can be applied to construction in the city center or residential area.

  Furthermore, by controlling the water pressure value P1 so as to be larger than the sum of the load due to the weight of the soil cement and the frictional force of the inner peripheral surface of the well drilling guide tube 6, the soil cement can be prevented from popping out. Soil cement can be moved slowly and safely upwards. Moreover, the water feeder 8 can be efficiently operated by managing the pressure value P1 of the water so as to cope with the change in the weight of the soil cement that is reduced by discharging the soil cement.

  In addition, since water is injected below the soil cement in the well drilling guide pipe 6, the soil cement is discharged to the ground in a dry state. Compared with the case where the wet soil cement is discarded, the dry soil cement does not require equipment such as a water removal device or a wastewater treatment device, and thus can reduce costs such as equipment costs. Furthermore, since the dried soil cement can be processed as industrial waste as it is, it does not require time and effort for disposal.

  And the well constructed by the above-mentioned method can prevent the collapse of the hole wall because the well drilling guide 1 is installed. Therefore, it becomes possible to confirm the groundwater level reliably for a long period of time.

  Moreover, since the soil cement column wall 2 provided with the well built by the method mentioned above does not need to ensure the space for installing a well, the inside of a work site can be used effectively. And by draining the groundwater through this well, the level of the pressured groundwater is lowered, so that the swell is prevented when the planned excavation site 5 surrounded by the soil cement column wall 2 is opened by the open-cut method. be able to.

  Next, a second embodiment of the present invention will be described. In the following description, portions corresponding to the above-described embodiment are denoted by the same reference numerals, description thereof is omitted, and differences are mainly described.

The discharge of the soil cement in the second embodiment of the present invention is performed while keeping the water injection pressure constant.
FIG.11 and FIG.12 is a figure which shows the installation procedure of the guide 1 for well drilling which concerns on 2nd embodiment of this invention.

  As shown in FIG. 11, a water feeder 8 such as a water pump installed on the ground is operated to press-fit water into the well drilling guide pipe 6. At this time, water is injected until the pressure of the water stored in the well drilling guide pipe 6 reaches the pressure value P2. In the present embodiment, the pressure value P2 is set to a value slightly larger than the water pressure Wp of the groundwater under pressure for the purpose of preventing boiling.

  Next, as shown in FIG. 12, the earth auger 22 is inserted through the opening on the upper end side of the well drilling guide pipe 6, and is sequentially crushed with anhydrous water from the top to the bottom of the soil cement and discharged to the ground. .

As the soil cement is discharged to the ground, the thickness of the soil cement decreases. When this thickness becomes Z2, the pressure (= γt × Z2) due to the weight of the soil cement and the friction force of the soil cement (= Z2 × f / r) ) And the sum of the pressure value P2 and the water pressure value P2 and the load of the soil cement are balanced. That means
P2 = γt × Z2 + Z2 × f / r (8)
Is established.

When the soil cement is further discharged from the state shown in the equation (8), the thickness of the soil cement becomes thinner than Z2, and when the thickness becomes Z3 (<Z2), the water pressure value P2 is the pressure due to the weight of the soil cement. It becomes larger than the total value of (= γt × Z2) and the frictional force (= Z2 × f / r) of the soil cement. That means
P2> γt × Z3 + Z3 × f / r (9)
Is established.

  When the formula (9) is satisfied, the soil cement is pushed upward by water pressure. When the soil cement moves upward, as shown in FIG. 13, water having a pressure value P2 of the same volume as the moved soil cement is injected into the well drilling guide tube 6. Thus, when water is supplied while maintaining the pressure value P2, the soil cement reaches the ground and is discharged from the well drilling guide pipe 6. When all the soil cement in the well drilling guide tube 6 is discharged, the well drilling guide tube 6 is replaced with water.

  According to the method for installing the well drilling guide 1 in the present embodiment described above, water is injected into the lower end portion of the well drilling guide pipe 6 and the inflow of the pressurized groundwater is caused by the pressure of the water. While holding down, the soil cement existing in the well drilling guide pipe 6 is pushed upward and discharged to the outside, and the inside of the well drilling guide pipe 6 is replaced with this water. Groundwater and earth and sand do not flow into the well drilling guide pipe 6 from the lower end of the drilling guide pipe 6. Therefore, it is possible to prevent boiling.

  Further, since the earth auger 22 is inserted from the upper end side opening of the well drilling guide pipe 6 and the soil cement is crushed and discharged, the soil cement is discharged in a short time and the inside of the well drilling guide pipe 6. Can be replaced with water.

Next, a third embodiment of the present invention will be described.
FIG. 14A to FIG. 14C are views showing a well drilling guide 31 according to the third embodiment of the present invention.

  As shown in FIGS. 14A to 14C, the well drilling guide 31 includes a well drilling guide pipe 6 and a closing means for closing the lower end surface of the well drilling guide pipe 6. 32.

The closing means 32 includes a lid 33 that closes the lower end surface of the well drilling guide pipe 6 and a closing device that closes the lid 33.
The lid 33 is a disk-shaped plate material having the same length as the inner diameter of the well drilling guide tube 6, and cylindrical pins 34 are attached to both ends in the diameter direction.

  A notch 37 for engaging the pin 34 of the lid 33 is formed at the lower end of the well drilling guide pipe 6. When the pin 34 is assembled so as to engage with the notch 37, the lid 33 is rotatable about the axial direction of the pin 34 (that is, the diameter direction of the lid 33) and the lower end of the well drilling guide tube 6 Attached to.

  The closing device includes a wire rope 35 attached to a part of the lid 33 and a winder (FIG. 15) that is installed on the ground and winds the wire rope 35. The lid 33 can be rotated by operating the wire rope 35. The wire rope 35 is disposed along the outer peripheral surface from the lower end to the upper end of the well drilling guide pipe 6.

Next, a method for installing the well drilling guide 31 in the soil cement column wall 2 will be described.
15-17 is a figure which shows the installation procedure of the guide 31 for well drilling which concerns on this embodiment.

As shown in FIG. 15, the well drilling guide pipe 6 is built into the unsolidified soil cement column wall 2 so that the end on the side where the lid 33 is attached is down.
At this time, in order to reduce resistance at the time of building in soil cement, the wire rope 35 is operated by the winder 36 installed on the ground to keep the lid 33 in a vertical state. For this reason, the lower end of the well drilling guide pipe 6 is opened at the time of installation, and the soil cement flows into the well drilling guide pipe 6. The erection is performed until the lid 33 attached in the well drilling guide pipe 6 passes through the soil cement column wall 2 and reaches the sand layer 4.

  And as shown in FIG. 16, the wire rope 35 is operated with the winder 36, the lid | cover 33 is rotated in a horizontal state, and the lower end surface of the well drilling guide pipe 6 is closed. The wire rope 35 is fixed in a tensioned state so that the lid 33 is rotated by the pressure Wp of the groundwater under pressure and the lower end surface is not opened.

  Next, as shown in FIG. 17, the earth auger 22 is inserted from the opening on the upper end side of the well drilling guide pipe 6 to crush the soil cement and discharge it to the ground. After all the soil cement in the well drilling guide tube 6 has been discharged, water is injected into the well drilling guide tube 6 to fill the well drilling guide tube 6 with water.

  Finally, as in the first embodiment, a rod 13 having a drilling bit is inserted into the well drilling guide tube 6, and the lid 33 is crushed using the well drilling guide tube 6 as a guide for drilling. However, a hole is drilled to the sand layer 4 to construct a well.

  According to the method for installing the well drilling guide 31 in the present embodiment described above, the lower end surface of the well drilling guide pipe 6 is closed with the lid 33, and the lid 33 suppresses the inflow of the pressurized groundwater to the soil. Since the cement is discharged to the outside, groundwater and earth and sand do not flow into the well drilling guide pipe 6 from the lower end of the well drilling guide pipe 6. Therefore, boiling can be prevented. When inserting the well drilling guide pipe 6 into the soil cement, the lid 33 is kept vertical and the lower end surface of the well drilling guide pipe 6 is kept open, so that the resistance is low and the insertion work is easy. It can be done.

  Further, since the earth auger 22 is inserted from the upper end side opening of the well drilling guide pipe 6 and the soil cement is crushed and discharged, the soil cement is discharged in a short time and the inside of the well drilling guide pipe 6. Can be replaced with water.

  Furthermore, the soil cement can be discharged to the ground in a dry state. Therefore, compared with the case where the soil cement in a wet state is discarded, it is possible to reduce costs such as equipment costs because there is no need for equipment such as a water removal device or a waste water treatment device.

Next, a fourth embodiment of the present invention will be described.
FIG. 18 is a view showing a well drilling guide 41 according to the fourth embodiment of the present invention. As shown in FIG. 18, the well drilling guide 41 includes a well drilling guide pipe 6, a pressure feed pipe 9, and a closing means 32.

Hereinafter, a method of installing the well drilling guide pipe 6 in the soil cement column wall 2 will be described.
FIGS. 19-21 is a figure which shows the installation procedure of the well drilling guide 41 which concerns on this embodiment.

As shown in FIG. 19, the well drilling guide pipe 6 is built in the soil cement column wall 2 until the lid 33 attached in the well drilling guide pipe 6 reaches the sand layer 4.
As shown in FIG. 20, the wire rope 35 is operated by the winder 36 to rotate the lid 33 in a horizontal state to close the lower end surface of the well drilling guide tube 6.
Next, as shown in FIG. 21, when water feeder 8 installed on the ground is operated and water is injected into pressure feed pipe 9, the soil cements soil cement at the lower end in well drilling guide pipe 6. Inflow and store while pushing up. In this state, water is injected until the water in the well drilling guide pipe 6 reaches the pressure value P1.
As in the first embodiment, the soil cement in the well drilling guide pipe 6 is moved upward by the pressure of the water stored in the well drilling guide pipe 6 and discharged to the outside. The hole guide tube 6 is filled with water.

  According to the method for installing the well drilling guide 41 in the present embodiment described above, the lower end surface of the well drilling guide pipe 6 is closed with the lid 33, and the lid 33 suppresses the inflow of the pressured groundwater to the soil. Since the cement is discharged to the outside, groundwater and earth and sand do not flow into the well drilling guide pipe 6 from the lower end of the well drilling guide pipe 6. Therefore, it is possible to prevent boiling.

  Further, by injecting water into the lower end portion of the well drilling guide tube 6, the pressure of the water acts in a direction to close the lid 33 of the well drilling guide tube 6, so the well drilling guide tube 6. The lower end surface of the can be securely closed.

Next, a fifth embodiment of the present invention will be described.
22-24 is a figure which shows the installation procedure of the guide 51 for well drilling which concerns on 5th embodiment of this invention.

  As shown in FIG. 22, a well drilling guide pipe 51 including only the well drilling guide pipe 6 is installed in the soil cement column wall 2. Then, the earth auger 22 is inserted from the opening on the upper end side of the well drilling guide pipe 6, and it is crushed in an anhydrous manner from the top to the bottom of the soil cement and discharged to the ground.

  Next, as shown in FIG. 23, the soil cement in the well drilling guide pipe 6 is excavated until the thickness of the soil cement becomes Z2 (see the formula (8)). As shown in the second embodiment, the thickness of the soil cement Z2 is the sum of the pressure of the soil cement due to its own weight (= γt × Z2) and the frictional force of the soil cement (= Z2 × f / r). Are equal to each other, and the pressure value P2 of the groundwater is balanced with the load of the soil cement. In order to reliably suppress the inflow of groundwater and earth and sand with the soil cement, the thickness of the soil cement remaining in the well drilling guide pipe 6 may be Z3 (Z3> Z2) slightly thicker than Z2.

  Next, as shown in FIG. 24, water is poured into the portion of the well drilling guide pipe 6 where the soil cement has been removed, and the remaining soil cement 2A is filled with water.

  Finally, as in the first embodiment, a rod 13 having a drilling bit is inserted into the well drilling guide pipe 6, and the well drilling guide pipe 6 is used as a guide for drilling to the sand layer 4. Drill a hole and build a well.

  According to the method of installing the well drilling guide 51 in the present embodiment described above, the earth auger 22 is inserted from the opening on the upper end side of the well drilling guide tube 6 to crush and discharge the soil cement. Therefore, the soil cement can be discharged in a short time and the inside of the well drilling guide pipe 6 can be replaced with water.

  In all the embodiments described above, a round steel pipe is used as the well drilling guide pipe 6. However, the well pipe is not limited to a round shape, and a square shape such as a square shape may be used.

  In all the embodiments described above, the case where the well drilling guide 1 is installed so as to pass through the soil cement column wall 2 is not limited to this. For example, well drilling It may be installed so that the depth of the lower surface of the guide 1 is the same as the depth of the lower surface of the soil cement column wall 2 or slightly shallower than the lower surface of the soil cement column wall 2 In this case, if the soil cement in the well drilling guide 1 is discharged by the earth auger 22, the well is drilled by penetrating the lower surface of the soil cement column wall 2 with the rod 13 having a drill bit. Good.

  In all the embodiments described above, the case where the well drilling guide pipe 1 is installed in the soil cement column wall 2 is described. However, the present invention is not limited to the wall. You may install in.

  Moreover, in all the embodiments described above, the application to a place where pressurized groundwater exists in the ground has been described, but the present invention is not limited to this, and can be applied to a place where self-injection occurs even in non-pressure groundwater. .

It is a perspective sectional view showing the state where the guide for well drilling concerning the first embodiment of the present invention was installed in the soil cement column wall. It is a longitudinal cross-sectional view which shows the state which installed the guide for well drilling which concerns on 1st embodiment of this invention in the soil cement column wall. It is sectional drawing of the guide for well drilling which concerns on this embodiment. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the installation procedure of the guide for well drilling which concerns on 2nd embodiment of this invention. It is a figure which shows the installation procedure of the guide for well drilling which concerns on 2nd embodiment of this invention. It is a figure which shows the installation procedure of the guide for well drilling which concerns on 2nd embodiment of this invention. It is a figure which shows the guide for well drilling which concerns on 3rd embodiment of this invention. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the guide for well drilling which concerns on 4th embodiment of this invention. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the guide for well drilling which concerns on 5th embodiment of this invention. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment. It is a figure which shows the installation procedure of the guide for well drilling which concerns on this embodiment.

Explanation of symbols

1 Guide for drilling wells 2 Soil cement column wall 3 Clay layer (impermeable layer) 4 Sand layer (pressured aquifer)
5 Drilling location 6 Well drilling guide pipe 7 Water supply port 8 Water feeder 9 Pressure feed pipe 10 Pressure sensor 11 Water stop means 12 Pile driver 13 Rod 22 Earth auger 31 Well drilling guide 32 Closing means 33 Lid 34 Pin 35 Wire rope 36 Winder 37 Notch 41, 51 Well drilling guide P1 Pressure value P2 Pressure value

Claims (15)

It is a construction method of underground structure where pipes are buried,
An installation step of providing a curing material in the ground in a fluidized state, which hardens over time and constitutes the underground structure;
An insertion step of inserting a cylindrical tube having both ends open into the hardened material in a fluid state;
An inflow prevention step for preventing fluids such as earth and sand and groundwater from flowing into the pipe from the lower end of the pipe.   2. The ground according to claim 1, wherein in the inflow prevention step, the fluid is prevented from flowing into the tube by its own weight while replacing the hardener present in the tube with a liquid. Medium construction method.   2. The underground construction method according to claim 1, wherein, in the inflow prevention step, the lower end of the pipe is closed by a closing means to prevent the fluid from flowing into the pipe.   In the flow prevention step, a predetermined amount of the hardener is left at a lower end portion in the pipe, and the flow of the fluid into the pipe is prevented by the weight of the left hardener. The construction method for underground structure according to claim 1.   The pipe is connected to a water supply port provided at a lower portion of the pipe, and is connected to a pressure feed pipe for feeding a liquid such as water or muddy water into the pipe. Construction method of underground structure in any one of 1-3.   The water supply port is provided with a water stop means that opens when the liquid in the pressure feed pipe becomes higher than a predetermined pressure and can supply the liquid into the pipe. Construction method of the underground structure described.   7. The underground construction method according to claim 6, wherein the water stop means is a check valve or a water stop cock provided from the inside of the pipe. The closing means is
A lid for closing the lower end surface of the tube;
A wire rope disposed along the outer peripheral surface of the tube and having one end connected to the lid;
The construction method of the underground structure according to claim 3, wherein the other end of the wire rope is connected and a winder for winding the wire rope. The lid has a disk shape, and includes protrusions at both ends in the diameter direction.
The tube includes a notch for engaging the protrusion on the one end side,
The underground construction method according to claim 8, wherein the lid is rotatably attached to the pipe by engaging the protrusion of the lid with the notch of the pipe. .   The underground construction method according to any one of claims 1 to 9, wherein a well is constructed in the underground structure by excavating a hole in the pipe to a predetermined depth.   The underground pipe construction method according to claim 10, wherein the pipe is embedded so that a lower end portion of the pipe protrudes below a lower end of the underground structure.   The underground pipe construction method according to any one of claims 1 to 11, wherein the pipe is a core material of the underground structure.   The construction method for an underground structure according to any one of claims 1, 2, and 4, wherein the hardening material includes either soil cement or concrete.   The underground construction structure construction method according to any one of claims 1 to 12, wherein the underground structure is any one of a wall, a pile, and a wall pile.   An underground structure constructed by the construction method according to claim 1.

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