Construction method for basement bottom plate water seepage under karst landform condition
Technical Field
The invention relates to a construction method for basement bottom plate water seepage under a karst landform condition, and belongs to the technical field of waterproof engineering in building construction.
Background
Karst landform widely distributes in the precious plateau region of china's cloud, leads to the rock crack big because of its soluble rock characteristics, the water permeability is strong, very easily forms local high pressure-bearing water spot, and this phenomenon leads to the bottom plate to appear the seepage condition more in the building work in-process, and the foundation bottom plate of building easily causes the phenomenon of bottom plate fracture infiltration because of the water pressure influence in high pressure-bearing water region, consequently needs in time to dredge to bottom plate pressure-bearing water. The traditional construction method for plugging, grouting and hydrophobic layer is not only troublesome in construction, but also is easy to cause water seepage repeatedly, and the drainage effect is not obvious.
Disclosure of Invention
The invention aims to provide a construction method for basement bottom plate water seepage under karst landform conditions, which is convenient to construct, low in cost and obvious in drainage effect, so as to overcome the defects in the prior art.
The technical scheme of the invention is as follows: a construction method for basement bottom board water seepage under the condition of karst landform is characterized by firstly calculating the maximum water inflow amount of basement bottom board water seepage according to the following formula:
in the formula:
q-water inflow
R-radius of influence, determined from the well data
r-radius of pile hole
h0Length of effective water inlet section
S-pile hole water level depth reduction
K-permeability coefficient
lgRAnd lgrThe values are taken according to the second volume of the Water supply hydrology and geology handbook
When the water inflow Q is less than 60m3D, when the water head pressure is less than 0.1Mpa, adopting anchor rod compaction pressure-resistant method to make construction, when the water inflow Q is greater than or equal to 60m3And d, when the water head pressure is more than or equal to 0.1Mpa, constructing by adopting a buried pipe drainage method.
In the method, when the drill rod anchor compaction pressure-resistant method is adopted for construction, firstly two or more water-swelling water stop strips are fixed on the rod body of the pressure-resistant anchor rod, then a water drill is adopted for drilling at the water seepage position of the basement bottom plate, the prefabricated pressure-resistant anchor rod is hammered into the drilled hole, and finally cement mortar is adopted for plugging the upper end of the pressure-resistant anchor rod.
In the method, the plugging agent is blended in the cement mortar, and the ratio of the cement mortar to the plugging agent is 1: 2.
In the method, when the pipe burying dredging method is adopted for construction, firstly, water seepage holes are formed in the pipe wall of the lower portion of the prefabricated steel pipe, a filter screen sleeve is sleeved on the lower portion of the prefabricated steel pipe, then a water drill is adopted for drilling holes in the water seepage position of the basement bottom plate, then the lower portion of the prefabricated steel pipe is inserted into the drilled holes for fixing, gaps between the prefabricated steel pipe and the drilled holes are plugged, at the moment, the upper end of the prefabricated steel pipe is connected with a drainage pipe, and therefore seepage water of the basement bottom plate enters the prefabricated steel pipe from the water seepage holes, and then the seepage water is drained to an indoor water collecting well through the drainage pipe and drained out, and the effect of.
In the method, the middle part of the prefabricated steel pipe is welded with the annular plate, the annular plate is uniformly provided with the through holes, and the expansion bolts penetrate through the through holes and then are fixed on the basement bottom plate, so that the prefabricated steel pipe can be fixed in the drill hole.
In the method, the rubber pad is arranged at the bottom of the annular plate and sleeved on the prefabricated steel pipe.
In the method, the backwashing device is inserted into the prefabricated steel pipe, and when more impurities are deposited in the prefabricated steel pipe 2, the backwashing device can be pulled up and down to clean the prefabricated steel pipe in order to prevent the impurities from blocking the water seepage holes.
In the method, the backwashing device is composed of a pull rod and a cleaning ring connected to the lower end of the pull rod.
In the method, the upper end of the prefabricated steel pipe is provided with a threaded joint, and the prefabricated steel pipe is connected with a drain pipe through the threaded joint.
Due to the adoption of the technical scheme, the invention has the advantages that: the invention solves the pressure condition of local high-pressure water from the root by adopting the measures of pressure resistance and pressure relief respectively, thereby having good prevention and control effect, having the characteristics of low construction cost, obvious effect, reliable quality, easy construction and the like, being widely applied to the engineering of abundant underground water under the condition of karst landform and having practicability and wide popularization.
Drawings
FIG. 1 is a schematic structural view of a buried pipe dredging method;
FIG. 2 is a schematic structural diagram of a backwashing device;
FIG. 3 is a top view of FIG. 2;
FIG. 4 is a schematic structural view of the implementation of the compression method of the anchor rod.
Description of reference numerals: 1-threaded joint, 2-prefabricated steel pipe, 3-annular plate, 4-expansion bolt, 5-rubber pad, 6-filter screen sleeve, 7-backwashing rod, 8-bottom plate, 9-water seepage hole, 10-pull rod, 11-cleaning ring, 12-pressure-resistant anchor rod, 13-water-expansion water stop bar and 14-cement mortar.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings and examples.
The embodiment of the invention comprises the following steps: a construction method for basement bottom board water seepage under the condition of karst landform is characterized by firstly calculating the maximum water inflow amount of basement bottom board water seepage according to the following formula:
in the formula:
q-water inflow
R-radius of influence, determined from the well data
r-radius of pile hole
h0Length of effective water inlet section
S-pile hole water level depth reduction
K-permeability coefficient
lgRAnd lgrThe values are taken according to the second volume of the Water supply hydrology and geology handbook
When the water inflow Q is less than 60m3D, when the water head pressure is less than 0.1Mpa, adopting anchor rod compaction pressure-resistant method to make construction, when the water inflow Q is greater than or equal to 60m3And d, when the water head pressure is more than or equal to 0.1Mpa, constructing by adopting a buried pipe drainage method.
Referring to fig. 1, when the pipe burying dredging method is adopted for construction, firstly, a water seepage hole 9 is formed in the pipe wall of the lower portion of a prefabricated steel pipe 2, a filter screen sleeve 6 is sleeved on the lower portion of the prefabricated steel pipe 2, then a water drill is adopted for drilling at the water seepage position of a basement bottom plate, then the lower portion of the prefabricated steel pipe 2 is inserted into the drill hole for fixing, a gap between the prefabricated steel pipe 2 and the drill hole is plugged, at the moment, the upper end of the prefabricated steel pipe 2 is connected with a water drainage pipe through a threaded connector 1, so that the water seepage of the basement bottom plate enters the prefabricated steel pipe 2 from the water seepage hole 9, the water seepage is drained to an indoor water collecting well through the water drainage pipe and is discharged. The middle part welding of prefabricated steel pipe 2 has annular slab 3, and the equipartition has the through-hole on annular slab 3, and expansion bolts 4 will be fixed on the basement bottom plate at annular slab 3 after passing the through-hole, alright make prefabricated steel pipe 2 fix in the drilling like this. The bottom of annular plate 3 is provided with rubber pad 5, and rubber pad 5 cover is on prefabricated steel pipe 2, prevents further water in the drilling to ooze through rubber pad 5. The backwashing device 7 is inserted into the prefabricated steel pipe 2, and when more impurities are deposited in the prefabricated steel pipe 2, the backwashing device 7 can be pulled up and down to clean the prefabricated steel pipe 2 in order to prevent the impurities from blocking the water seepage holes 9. Referring to fig. 2 and 3, the backwashing device 7 is composed of a draw bar 10 and a cleaning ring 11 connected to the lower end of the draw bar 10.
Referring to fig. 4, when the construction is performed by adopting the drill rod anchor compaction and pressure resistance method, four water-swelling water stop strips 13 are fixed on the rod body of the pressure resistant anchor rod 12, then a water drill is used for drilling at the water seepage position of the basement bottom plate, the prefabricated pressure resistant anchor rod 12 is hammered into the drilled hole, and finally cement mortar is used for plugging the upper end of the pressure resistant anchor rod 12. The cement mortar 14 is blended with a plugging agent, and the ratio of the cement mortar 14 to the plugging agent is 1: 2.
In conclusion, the pressure-resistant and pressure-relief measures are adopted respectively to radically solve the pressure condition of local high-pressure water, so that the method has a good prevention and control effect, has the characteristics of low construction cost, obvious effect, reliable quality, easiness in construction and the like, can be widely applied to underground water-rich projects under karst landform conditions, and has practicability and wide popularization.