LU506351B1 - Distributed monitoring method for stress and deformation of foundation pit supporting anchor rods - Google Patents
Distributed monitoring method for stress and deformation of foundation pit supporting anchor rods Download PDFInfo
- Publication number
- LU506351B1 LU506351B1 LU506351A LU506351A LU506351B1 LU 506351 B1 LU506351 B1 LU 506351B1 LU 506351 A LU506351 A LU 506351A LU 506351 A LU506351 A LU 506351A LU 506351 B1 LU506351 B1 LU 506351B1
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- Luxembourg
- Prior art keywords
- anchor rod
- optical cable
- sensing optical
- anchor
- led out
- Prior art date
Links
- 238000012544 monitoring process Methods 0.000 title description 13
- 238000000034 method Methods 0.000 title description 5
- 230000003287 optical effect Effects 0.000 claims abstract description 39
- 238000012806 monitoring device Methods 0.000 claims abstract description 10
- 229910000831 Steel Inorganic materials 0.000 claims description 10
- 239000002689 soil Substances 0.000 claims description 10
- 239000010959 steel Substances 0.000 claims description 10
- 239000011347 resin Substances 0.000 claims description 8
- 229920005989 resin Polymers 0.000 claims description 8
- 238000003466 welding Methods 0.000 claims description 4
- 239000011435 rock Substances 0.000 claims description 3
- 239000013307 optical fiber Substances 0.000 description 7
- 238000010276 construction Methods 0.000 description 6
- 230000008901 benefit Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000011068 loading method Methods 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000004873 anchoring Methods 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000004083 survival effect Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 238000009412 basement excavation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000007596 consolidation process Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000013480 data collection Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
- E21D21/02—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection having means for indicating tension
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Structural Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Force Measurement Appropriate To Specific Purposes (AREA)
Abstract
The invention discloses a distributed monitoring device for foundation pit anchor rods, which comprises a first anchor rod and a second anchor rod; a sensing optical cable arranged along an axis direction is arranged on an outer wall where the first anchor rod is located; one end of the sensing optical cable is connected to a control center, and another end is led out from a tail of the first anchor rod along an axis outer wall to a head, and then reversely led out; a front end of the second anchor rod is provided with two groups of expanders, and at the same time, the expanders expand outward; and the sensing optical cable led out from the first anchor rod continues to be led out from a tail of the second anchor rod along an axis outer wall to a head and then reversely led out.
Description
DESCRIPTION LU506351
DISTRIBUTED MONITORING METHOD FOR STRESS AND DEFORMATION
OF FOUNDATION PIT SUPPORTING ANCHOR RODS
The invention belongs to the technical field of foundation pit monitoring, in particular to a distributed monitoring device for foundation pit anchor rods.
With the acceleration of urbanization, a large number of high-rise buildings are constantly being built, and depths and scales of foundation pits are increasing, so requirements for stability of foundation pit engineering are getting higher and higher.
As a main means of foundation pit support, an anchor rod has the advantages of light structure, strong flexibility, good ductility, low cost, simple construction, strong adaptability, short construction period, and little impact on the environment, and is widely used in foundation pit support.
With the excavation of the construction of deep foundation engineering, unloading of a soil mass in the foundation engineering will cause the rebound of a substrate. A retaining structure interacts with the soil mass around a foundation project. If a supporting structure is not designed properly, it will cause insufficient stiffness and strength, which will lead to supporting structure tilting, even soil landslides and foundation project collapse. At the same time, engineering geological problems caused by a dewatering process of foundation engineering construction are also frequent, such as uneven ground settlement of a surrounding soil mass caused by soil consolidation, even ground fissure disasters, sand loss caused by pumping water in sandy soil stratum and even piping quicksand accidents.
As a main means of foundation support, the anchor rod has the advantages of LU506351 light structure, strong flexibility, good ductility, low cost, simple construction, strong adaptability, short construction period, and little impact on the environment, and is widely used in the foundation support, so it is very important to evaluate a working performance and a long-term reinforcement effect of the anchor rod in foundation engineering support. Therefore, it is necessary to adopt corresponding technical means to monitor a strain change of the anchor rod in the process of foundation engineering support.
In view of the shortcomings of the prior art, an objective of the invention is to provide a distributed monitoring device for foundation pit anchor rods, which solves the above technical problems existing in the prior art.
The objective of the invention may be realized by a following technical scheme.
The invention relates to a distributed monitoring device for foundation pit anchor rods, which comprises a first anchor rod and a second anchor rod; the first anchor rod has a straight tubular structure, and at the same time, a sensing optical cable arranged along an axis direction is arranged on an outer wall where the first anchor rod is located; one end of the sensing optical cable is connected to a control center, and another end is led out from a tail of the first anchor rod along an axis outer wall to a head, and then reversely led out; a front end of the second anchor rod is provided with two groups of expanders, and at the same time, the expanders expand outward and reinforce a rock and soil mass on an inner wall of a borehole, so that an anchoring performance of the anchor rod is improved; and the sensing optical cable led out from the first anchor rod continues to be led out from a tail of the second anchor rod along an axis outer wall to a head and then reversely led out; the first anchor rod and the second anchor rod are horizontally arranged up and down in horizontal boreholes in strata with different depths in a foundation pit.
Further, the first anchor rod and the second anchor rod are respectively LU506351 connected in a multi-section tubular distribution and are respectively connected with each other through a flange piece.
Furthermore, two groups of steel bar pieces are arranged on each of the outer walls where the first anchor rod and the second anchor rod are located along a symmetrical axis direction, and the sensing optical cable is arranged in a gap between each of the steel bar pieces and the each of the outer walls of the first anchor rod and the second anchor rod.
Further, each of the outer walls where the first anchor rod and the second anchor rod are located is wrapped with a resin-coated film layer, so that the sensing optical cable is wrapped on each of the outer walls where the first anchor rod and the second anchor rod are located; meanwhile, a duct tape is arranged at an outer side where the resin-coated film layer is located.
Further, the sensing optical cable led out from the first anchor rod and the sensing optical cable led in from the second anchor rod are connected by welding.
The invention has the following beneficial effects. 1. The sensing optical cable on the first anchor rod and the second anchor rod is used in this device to measure situations in the boreholes with different depths at the same time, and continuity of sensing data of the sensing optical cable is realized by welding, thus improving a monitoring accuracy. 2. Compared with a traditional point sensor, the most obvious advantage of a distributed optical fiber sensing technology is that it may measure a strain of each point along a sensing optical fiber, realize the fully distributed monitoring of stress and deformation of the anchor rod, overcome shortcomings of traditional point monitoring such as missed detection and numerous leads, and greatly improve monitoring efficiency. 3. The sensing optical cable used in this device is light in weight and small in volume, which is easy to lay and install on the anchor rod, and may obtain reliable monitoring data for evaluating the safety and stability of foundation engineering.
BRIEF DESCRIPTION OF THE FIGURES LU506351
To explain a technical scheme in an embodiment of the present invention or the prior art more clearly, drawings needed in the description of the embodiment of the prior art will be briefly introduced below.
FIG. 1 is a schematic diagram of the overall structure of an embodiment of the invention:
FIG. 2 is a schematic diagram of the overall structure of the first anchor rod in the embodiment of the invention;
FIG. 3 is a schematic diagram of a cross-sectional structure of the first anchor rod in the embodiment of the invention;
FIG. 4 is a schematic diagram of the overall structure of a second anchor rod in the embodiment of the invention.
In the following, a technical scheme in an embodiment of the invention will be clearly and completely described with attached drawings. Based on the embodiment in this invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of this invention.
As shown in FIG. 1, the embodiment of the invention provides a distributed monitoring device for foundation pit anchor rods, which comprises a first anchor rod 1 and a second anchor rod 2. As shown in FIGS. 2 and 3, the first anchor rod 1 has a straight tubular structure, and at the same time, a sensing optical cable 3 arranged along an axis direction is arranged on an outer wall where the first anchor rod 1 is located. One end of the sensing optical cable 3 is connected to a control center, and another end is led out from the tail of the first anchor rod 1 along an axis outer wall to a head, and then reversely led out along a symmetrical axis outer wall. At this time, the first anchor rod 1 is connected in multi-section tubular distribution and is connected with each other through a flange piece 101.
The outer wall where the first anchor rod 1 is located is provided with two groups LU506351 of symmetrical steel bar pieces 102 along an axial direction, and the sensing optical cable 3 is arranged in a gap between the steel bar pieces 102 and the first anchor rod 1, so that the sensing optical cable 3 is prevented from being damaged by extrusion.
Then, the outer wall where the first anchor rod 1 is located is wrapped with a resin-coated film layer 11, so that the sensing optical cable 3 is wrapped on the outer wall where the first anchor rod 1 is located. Then, the steel bar pieces 102 are wrapped by the resin-coated film layer 11 and the outer wall of the sensing optical cable 3 is wrapped by duct tape 12 for the second time, which may reduce friction damage of a hole wall to a surface of the sensing optical cable 3 during a drilling process of the anchor rod, improve a survival rate of the sensing optical cable 3, and ensure its coupling performance with the anchor rod.
As shown in FIG. 4, the front end of the second anchor rod 2 (which is connected in a multi-section tubular distribution as required and connected with each other through the flange piece 101) is provided with two groups of expanders 21, and at the same time, the expanders 21 expand outward and reinforce a rock and soil mass on an inner wall of a borehole (suitable for soft soil layers), thus improving an anchoring performance of the anchor rod. The sensing optical cable 3 led out from the first anchor rod 1 and continues to be led out from the tail of the second anchor rod 2 along an axis outer wall to a head and then reversely led out along a symmetrical axis outer wall. At this time, an outer wall where the second anchor rod 2 is located is provided with two groups of symmetrical steel bar pieces 102 along an axis direction, so that the sensing optical cable 3 is arranged in a gap between the steel bar pieces 102 and the outer wall of the second anchor rod 2, and at this time, the sensing optical cable 3 is prevented from being damaged by friction. Subsequently, the outer wall where the second anchor rod 2 is located is wrapped with a resin-coated film layer 11 (not specifically shown in the figure, please refer to a similar arrangement of the first anchor rod 1), so that the sensing optical cable 3 is wrapped on the outer wall where the first anchor rod 1 is located, and then the steel bar pieces 102 wrapped with the resin-coated film layer 11 and the outer wall of the sensing optical cable 3 are wrapped by a duct tape 12 (not specifically shown in the figure, please refer to the similar arrangement of the first anchor rod 1) for the second time, which may reduce a LU506351 friction damage of an inner wall of a borehole to the surface of the sensing optical cable 3, improve the survival rate of the sensing optical cable 3, and ensure its coupling performance with the anchor rod (see the similar arrangement of the first anchor rod 1).
The sensing optical cable 3 led out from the first anchor rod 1 and the sensing optical cable 3 led in from the second anchor rod 2 are connected by welding. The first anchor rod 1 and the second anchor rod 2 are horizontally arranged in the boreholes of different depths in a foundation pit.
Specific usage: (1) an anchor rod with a strain-sensing optical cable is pressed horizontally into a pre-constructed horizontal borehole with a flat pusher. (2) Grouting materials with a matching ratio according to design requirements are selected for grouting. (3) When a grouting strength reaches specification requirements, a reaction device and related equipment for a drawing test are installed. (4) A cyclic loading method is usually used for loading. After each loading, optical fiber data collection is carried out after a load is stable until a whole loading test is finished.
A linear relationship between a change of spontaneous Brillouin scattering frequency and a strain change in optical fiber is used for fully distributed monitoring.
Compared with a traditional point sensor, the most obvious advantage of a distributed optical fiber sensing technology is that it may measure a strain of each point along a sensing optical fiber, realize the fully distributed monitoring of a monitored object, overcome shortcomings of traditional point monitoring such as missed detection and numerous leads, and greatly improve monitoring efficiency. Meanwhile, the optical fiber is light in weight and small in volume, which makes it easy to be laid and installed on the anchor rod. Therefore, this scheme puts forward a distributed anchor rod used for deep foundation engineering support monitoring to monitor and evaluate the safety and stability of foundation engineering.
After an installation is completed, the control center adopts a distributed data LU506351 acquisition system to collect data in the borehole through the sensing optical cable 3 located on the first anchor rod 1 and the second anchor rod 2.
The above shows and describes the basic principle, main features, and advantages of the invention. It should be understood by those skilled in the industry that the invention is not limited by the above-mentioned embodiments, and what is described in the above-mentioned embodiments and specifications only illustrates the principle of the invention. Under the premise of not departing from the spirit and scope of the invention, there will be various changes and improvements in the invention, which fall within the scope of the invention to be protected.
Claims (5)
1. A distributed monitoring device for foundation pit anchor rods, comprising a first anchor rod (1) and a second anchor rod (2), characterized in that the first anchor rod (1) has a straight tubular structure, and at the same time, a sensing optical cable (3) arranged along an axis direction is arranged on an outer wall where the first anchor rod (1) is located; one end of the sensing optical cable (3) is connected to a control center, and another end is led out from a tail of the first anchor rod (1) along an axis outer wall to a head, and then reversely led out; a front end of the second anchor rod (2) is provided with two groups of expanders (21), and at the same time, the expanders (21) expand outward and reinforce a rock and soil mass on an inner wall of a borehole, and the sensing optical cable (3) led out from the first anchor rod (1) continues to be led out from a tail of the second anchor rod (2) along an axis outer wall to a head and then reversely led out; the first anchor rod (1) and the second anchor rod (2) are horizontally arranged in horizontal boreholes in strata with different depths in a foundation pit.
2. The distributed monitoring device for foundation pit anchor rods according to claim 1, is characterized in that the first anchor rod (1) and the second anchor rod (2) are respectively connected in a multi-section tubular distribution, and are respectively connected with each other through a flange piece (101).
3. The distributed monitoring device for foundation pit anchor rods according to claim 2, is characterized in that two groups of steel bar pieces (102) are arranged on each of the outer walls where the first anchor rod (1) and the second anchor rod (2) are located along a symmetrical axis direction, and the sensing optical cable (3) is arranged in a gap between each of the steel bar pieces (102) and the each of the outer walls of the first anchor rod (1) and the second anchor rod (2).
4. The distributed monitoring device for foundation pit anchor rods according to LU506351 claim 1, is characterized in that each of the outer walls where the first anchor rod (1) and the second anchor rod (2) are located is wrapped with a resin-coated film layer (11), so that the sensing optical cable (3) is wrapped on the each of the outer walls where the first anchor rod (1) and the second anchor rod (2) are located; meanwhile, a duct tape (12) is arranged at an outer side where the resin-coated film layer (11) is located.
5. The distributed monitoring device for foundation pit anchor rods according to claim 4, is characterized in that the sensing optical cable (3) led out from the first anchor rod (1) and the sensing optical cable (3) led in from the second anchor rod (2) are connected by welding.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| LU506351A LU506351B1 (en) | 2024-02-07 | 2024-02-07 | Distributed monitoring method for stress and deformation of foundation pit supporting anchor rods |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| LU506351A LU506351B1 (en) | 2024-02-07 | 2024-02-07 | Distributed monitoring method for stress and deformation of foundation pit supporting anchor rods |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| LU506351B1 true LU506351B1 (en) | 2024-08-08 |
Family
ID=92424902
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| LU506351A LU506351B1 (en) | 2024-02-07 | 2024-02-07 | Distributed monitoring method for stress and deformation of foundation pit supporting anchor rods |
Country Status (1)
| Country | Link |
|---|---|
| LU (1) | LU506351B1 (en) |
-
2024
- 2024-02-07 LU LU506351A patent/LU506351B1/en active IP Right Grant
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| Date | Code | Title | Description |
|---|---|---|---|
| FG | Patent granted |
Effective date: 20240808 |