Pore water pressure gauge structure for measuring pore water pressure of soil body at bottom of foundation pit

Abstract

The invention provides a pore water pressure gauge structure for measuring the pore water pressure of a soil body at the bottom of a foundation pit, which comprises pore water pressure, an acquisition circuit board, a sealing cylinder and a tubular line gathering seat with the upper end connected to the lower end of the sealing cylinder, the pore water pressure gauge is connected to the lower end of the line gathering seat, and the acquisition circuit board is mounted in the sealing cylinder. The sealing cylinder is provided with a battery for supplying power to the acquisition circuit board, a wire of the acquisition circuit board penetrates through a threading hole in one end, connected with the wire gathering seat, of the sealing cylinder and then is connected with a wire of the pore water pressure gauge, and the joint of the wire of the acquisition circuit board and the wire of the pore water pressure gauge is located in the wire gathering seat. And a wire of the acquisition circuit board is hermetically connected with the threading hole. The invention aims to provide the pore water pressure gauge structure for measuring the pore water pressure of the soil body at the bottom of the foundation pit, which does not generate electric wires to interfere the construction of the foundation pit and is used for solving the problem that data of the existing pore water pressure gauge are led out of the foundation pit through the electric wires to interfere the construction of the foundation pit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of foundation pit construction monitoring equipment, and particularly relates to a pore water pressure gauge structure for measuring pore water pressure of soil at the bottom of a foundation pit. BACKGROUND

[0002] The pore water pressure response of soil in a foundation pit plays an important role in the control of foundation pit deformation and environmental deformation, so it is necessary to monitor the pore pressure during the construction of the foundation pit to obtain the relationship between the pore water pressure and time during the construction process, so as to provide a data basis for scientific construction of the foundation pit. The existing monitoring method is to bury the pore water pressure gauge at a deep position in the foundation pit, lengthen the wire of the pore water pressure gauge to connect with a data acquisition circuit board on the ground, connect the data acquisition circuit board with a computer, so as to realize data transmission, the data acquisition circuit board comprises a data collector and a data output device, the data collector is used for collecting the water pressure data detected by the pore water pressure gauge, and the data output device is used for outputting the water pressure data detected by the pore water pressure gauge to the computer in real time; this method has the following disadvantages: the wire penetrating the foundation pit will affect the construction of the foundation pit, and the excessively long wire will cause signal transmission distortion. SUMMARY

[0003] The present application aims to provide a pore water pressure gauge structure for measuring pore water pressure of soil at the bottom of a foundation pit, which will not cause wire interference to the construction of the foundation pit, so as to solve the problem that the data of the existing pore water pressure gauge is led out to the outside of the foundation pit through a wire, which will interfere with the construction of the foundation pit.

[0004] In order to achieve the above-mentioned object, the present application adopts the following technical scheme: a pore water pressure gauge structure for measuring pore water pressure of soil body at the bottom of a foundation pit, comprising a pore water pressure and a collecting circuit board, the collecting circuit board comprising a data collector and a data output device, the data collector being used for collecting water pressure data detected by the pore water pressure gauge, characterized in that the structure further comprises a sealing cylinder and a tubular polyline holder connected to the lower end of the sealing cylinder, the collecting circuit board further comprising a memory, the memory being used for storing the pore water pressure data detected by the pore water pressure gauge collected by the data collector, the data output device being used for outputting the pore water pressure data stored in the memory, the pore water pressure gauge being connected to the lower end of the polyline holder, the collecting circuit board being installed in the sealing cylinder, the sealing cylinder being provided with a battery for supplying power to the collecting circuit board, the electric wire of the collecting circuit board being connected to the electric wire of the pore water pressure gauge after passing through the wire passing hole on one end of the sealing cylinder and the polyline holder, the electric wire of the collecting circuit board being sealedly connected to the wire passing hole, the connection between the electric wire of the collecting circuit board and the electric wire of the pore water pressure gauge being located in the polyline holder, and the electric wire of the collecting circuit board being sealedly connected to the wire passing hole. The collecting circuit board is integrated in the sealing cylinder together with the pore water pressure gauge, and when used, the collecting circuit board and the pore water pressure gauge can be directly buried at the bottom of the foundation pit, so that the electric wire between the collecting circuit board and the pore water pressure gauge does not need to be led out from under the bottom of the foundation pit to the collecting circuit board located on the ground, and thus the phenomenon of electric wire interference with construction will not occur. The polyline holder is arranged, so that when the length of the electric wire of the collecting circuit board and the electric wire of the pore water pressure gauge needs to be coiled, the coiled part can be accommodated in the polyline holder, so that the electromagnetic field interference caused by the wire coiling will not interfere with the work of the collecting circuit board.

[0005] Preferably, the sealing cylinder comprises a cylinder body, an upper end cover detachably and sealingly connected to the upper end of the cylinder body, and a lower end cover detachably and sealingly connected to the lower end of the cylinder body, the wire passing hole is arranged on the lower end cover, and the electric wire of the collecting circuit board is sealingly arranged in the wire passing hole. The sealing cylinder is convenient to manufacture.

[0006] Preferably, the upper end cover is detachably and sealingly arranged at the upper end of the cylinder body, a plurality of upper end cover fixing bolts pass through the cylinder body and are threadedly connected to the upper end cover portion thread holes on the upper end cover, and the upper end cover fixing bolts are distributed along the circumference of the cylinder body; the lower end cover is detachably and sealingly arranged at the lower end of the cylinder body, a plurality of lower end cover fixing bolts pass through the cylinder body and are threadedly connected to the lower end cover portion cylinder side thread holes on the lower end cover, and the lower end cover fixing bolts are distributed along the circumference of the cylinder body. The cylinder body and the end cover are reliably fixed.

[0007] As preferred, the circumferential surface of the part of the upper end cover inserted into the cylinder is provided with two end cover part sealing grooves, the upper end cover is provided with two upper end cover part sealing rings located in the two upper end cover part sealing grooves, and the upper end cover part sealing rings seal and connect the upper end cover and the cylinder together; the circumferential surface of the part of the lower end cover inserted into the cylinder is provided with two end cover part sealing grooves, the lower end cover is provided with two lower end cover part sealing rings located in the two lower end cover part sealing grooves, and the lower end cover part sealing rings seal and connect the lower end cover and the cylinder together. The sealing is reliable.

[0008] As preferred, the lower end of the converging seat is provided with an end wall, the end wall is provided with a threaded hole, the pore water pressure gauge is provided with a threaded head, the wire of the pore water pressure gauge is led out from the end surface of the threaded head, and the threaded head is threadedly connected in the threaded hole; the diameter of the part of the lower end cover inserted into the cylinder is smaller than the diameter of the lower end cover, the lower end cover is inserted into the converging seat in a removable manner, and a plurality of converging seat fixing bolts are threadedly connected in the lower end cover part converging seat side threaded holes on the lower end cover after passing through the converging seat. The connection is reliable and convenient.

[0009] As preferred, the outer end surface of the upper end cover is provided with a threaded hole for installing a lifting wire. In use, a pore water pressure gauge installation hole is punched to a set depth at a site where a foundation pit is set, a threaded head is connected to the lifting wire, the threaded head is connected in the threaded hole, the wireless pore water pressure gauge is placed in the pore water pressure gauge installation hole through the lifting wire, the wireless pore water pressure gauge is covered with earth in the pore water pressure gauge installation hole to fix it in a required posture, the lifting wire is thrown into the pore water pressure gauge installation hole, and the filling of the pore water pressure gauge installation hole is continued until it is filled. The present application can conveniently maintain the existing posture in the soil at the site of the foundation pit to be excavated.

[0010] As preferred, the wire of the collecting circuit board is connected together with one end of a waterproof cable, the waterproof cable is sealingly connected in the wire hole, the wire of the pore water pressure gauge is connected to the other end of the waterproof cable, the wire hole is located in a large-diameter section of the converging seat, an elastic sealing ring is inserted in the large-diameter section, the elastic sealing ring sealingly connects the waterproof cable and the wire hole together, and a step is formed between the large-diameter section and the wire hole. The wire of the collecting circuit board and the wire of the pore water pressure gauge are not directly connected, but are connected through the waterproof cable, which can improve the sealing reliability of the sealing cylinder. A large-diameter section is provided in a section of the converging seat to form a step and install a sealing ring. When the water pressure is high, the sealing ring will be shortened in the axial direction and enlarged in the radial direction, so that the higher the water pressure, the better the sealing effect. If the direction is reversed, the greater the force with which the sealing ring is separated when the water pressure is high, and the more likely it is that the sealing is poor.

[0011] Preferably, the elastic sealing ring is sealed and fixed inside the wire hole by a sealing strip formed by adhesive. This improves the sealing reliability between the sealing ring and the large-diameter section. The sealing ring should not be glued to the waterproof cable adhesive, otherwise it will be inconvenient to remove the data acquisition circuit board.

[0012] Preferably, the threading hole is a straight hole, and an annular blade extending circumferentially along the threading hole is provided at one end of the large-diameter section of the threading hole. The cross-section of the annular blade is triangular, and the annular blade protrudes from the step. The inner circumferential surface of the annular blade and the circumferential surface of the threading hole are located on the same cylindrical surface. The cutting edge direction of the annular blade is the same as the center line direction of the threading hole. The surface of the waterproof cable is provided with an insulating plastic layer, and the diameter of the waterproof cable is larger than the diameter of the threading hole. In use, the waterproof cable is inserted into the threading hole from the end where the cable holder is located. During the insertion process, the annular blade cuts off a layer of the surface of the waterproof cable, thereby improving the sealing effect between the waterproof cable and the threading hole. The cut-off surface layer of the waterproof cable will compress the sealing ring, thereby improving the sealing effect of the sealing ring on the waterproof cable.

[0013] Preferably, the conductive core of the waterproof cable has a wiring hole with a larger inner end and a smaller outer end on one end face of the cable holder. The end of the wire of the pore water pressure gauge is knotted to form a clip that can pass through the wiring hole. The clip is inserted into the wiring hole, and the wiring hole is filled with conductive adhesive to form a clamp head. The clamp head adheres the wire of the pore water pressure gauge to the wiring hole. Since the wire at the cable holder end is exposed in the soil, it is prone to falling off due to soil erosion and water pressure. This connection method makes the connection more reliable.

[0014] The present invention has the following advantages: it can store the collected data first, and then export the data after retrieving the present invention, thereby eliminating the need to install wires in the foundation pit and avoiding interference from wires in the foundation pit construction. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the present invention; Figure 2 yes Figure 1 A magnified view of a portion of point A; Figure 3 yes Figure 2 A magnified view of a portion of point B; Figure 4 yes Figure 2 A magnified view of a portion at point C; Figure 5 yes Figure 4 A magnified view of a portion of point D.

[0016] In the diagram: 1. Pore water pressure gauge; 2. Acquisition circuit board; 3. Sealing cylinder; 4. Coiling seat; 5. Cylinder body; 6. Upper end cover; 7. Lower end cover; 8. Wires of acquisition circuit board; 9. Waterproof cable; 10. Threaded head; 11. Wires of pore water pressure gauge; 12. Battery; 13. Upper end cover fixing bolt; 14. Lower end cover fixing bolt; 15. Upper end cover sealing ring; 16. Lower end cover sealing ring; 17. Water inlet; 18. Coiling seat fixing bolt; 19. Threaded hole; 20. Large diameter section; 21. Elastic sealing ring; 22. Sealing strip; 23. Annular blade; 24. Cut-off waterproof cable surface layer; 25. Conductive core; 26. Wiring hole; 27. Clamping block; 28. Clamping head; 30. Step; 31. Plastic layer. Detailed Implementation

[0017] The present invention will now be described in conjunction with the accompanying drawings and specific embodiments, wherein the anchor rod is inclined with one end higher than the other end, which is connected to the inner retaining wall, and the lower end of the anchor rod is lower than the bottom of the inner pit.

[0018] See Figures 1 to 5A pore water pressure gauge structure for measuring pore water pressure at the bottom of a foundation pit includes a pore water pressure gauge 1, a data acquisition circuit board 2, a sealing cylinder 3, and a tubular cable holder 4 connected at its upper end to the lower end of the sealing cylinder. The data acquisition circuit board includes a data acquisition unit, a storage unit, and a data output unit. The data acquisition unit acquires the water pressure data detected by the pore water pressure gauge, the storage unit stores the pore water pressure data acquired by the data acquisition unit, and the data output unit outputs the pore water pressure data stored in the storage unit. The sealing cylinder includes a cylinder body 5, a detachable and sealed upper end cover 6 connected to the upper end of the cylinder body, and a detachable and sealed lower end cover 7 connected to the lower end of the cylinder body. A wire 8 from the data acquisition circuit board is connected to one end of a waterproof cable 9. The waterproof cable is sealed and passes through the wire passage. The pore water pressure gauge has a threaded head 10, which is connected to a threaded hole at the lower end of the cable holder. The wire 11 from the pore water pressure gauge is connected to the lower end of the waterproof cable. The data acquisition circuit board is installed inside the sealed cylinder. A battery 12, which powers the data acquisition circuit board, is located inside the sealed cylinder. The connection points between the wires of the data acquisition circuit board and the wires of the pore water pressure gauge are located inside the cable holder. The upper end cap is detachably inserted through the upper end of the cylinder. Several upper end cap fixing bolts 13 pass through the cylinder and are threaded into the threaded holes on the upper end cap. These upper end cap fixing bolts are distributed circumferentially around the cylinder. The lower end cap is detachably inserted through the lower end of the cylinder. Several lower end cap fixing bolts 14 pass through the cylinder and are threaded into the threaded holes on the lower end cap side of the lower end cap. These lower end cap fixing bolts are distributed circumferentially around the cylinder. The upper end cover has two sealing grooves on its circumferential surface where it is inserted into the cylinder. Two upper end cover sealing rings 15 are fitted within these grooves, sealing the upper end cover to the cylinder. Similarly, the lower end cover has two sealing grooves on its lower circumferential surface where it is inserted into the cylinder. Two lower end cover sealing rings 16 are fitted within these grooves, sealing the lower end cover to the cylinder. The lower end of the cable holder has an end wall with a threaded hole. The wire of the pore water pressure gauge is led out from the end face of the threaded head. The pore water pressure gauge has an inlet 17. The diameter of the portion of the lower end cover that passes through the cylinder is smaller than the diameter of the lower end cover itself. The lower end cover is removably inserted into the cable holder. Several cable holder fixing bolts 18 pass through the cable holder and are threaded into the cable holder side threaded holes on the lower end cover. The outer end face of the upper cover is provided with a threaded hole 19 for installing a suspension line. In use, a hole for installing the pore water pressure gauge is drilled to the set depth at the location of the foundation pit. A threaded head is connected to the suspension line and then connected to the threaded hole. The wireless pore water pressure gauge is placed into the hole using the suspension line. Soil is backfilled into the hole to cover the wireless pore water pressure gauge and fix it in the required position. The suspension line is then dropped into the hole, and backfilling continues until the hole is filled.A large-diameter section 20 is provided at the cable concentrator's end of the cable pass-through hole. An elastic sealing ring 21 passes through the large-diameter section, sealingly connecting the waterproof cable to the cable pass-through hole. A step 30 is formed between the large-diameter section and the cable pass-through hole. The elastic sealing ring is sealed and fixed inside the cable pass-through hole by a sealing strip 22 formed by adhesive. The cable pass-through hole is a straight hole. At one end of the large-diameter section, there is an annular blade 23 extending circumferentially along the cable pass-through hole. The cross-section of the annular blade is triangular, and the annular blade protrudes from the step. The inner circumferential surface of the annular blade and the circumferential surface of the cable pass-through hole are located on the same cylindrical surface. The cutting edge of the annular blade is in the same direction as the center line of the cable pass-through hole. The surface of the waterproof cable is covered with an insulating plastic layer 31, and the diameter of the waterproof cable is larger than the diameter of the cable pass-through hole. In use, the waterproof cable is inserted into the cable pass-through hole from the end where the cable concentrator is located. During insertion, the annular blade cuts off a layer of the surface of the waterproof cable, thereby improving the sealing effect between the waterproof cable and the cable pass-through hole. The cut surface layer 24 of the waterproof cable will compress the sealing ring, thereby improving the sealing effect of the sealing ring on the waterproof cable. The conductive core 25 of the waterproof cable (the wires of a pore water pressure gauge are connected together through a conductive core, and the conductive cores are insulated from each other) has a wiring hole 26 with a larger inner end and a smaller outer end on one end face of the cable holder. The end of the wire of the pore water pressure gauge is knotted to form a clip 27 that can be inserted into the wiring hole. The clip is inserted into the wiring hole, and the wiring hole is filled with conductive glue to form a clip head 28. The clip head glues the wire of the pore water pressure gauge into the wire hole.

Claims

1. A pore water pressure gauge structure for measuring pore water pressure in soil at the bottom of a foundation pit, comprising a pore water pressure gauge and a data acquisition circuit board, wherein the data acquisition circuit board includes a data acquisition unit and a data output unit, the data acquisition unit being used to acquire the water pressure data detected by the pore water pressure gauge, characterized in that, It also includes a sealing cylinder and a tubular cable holder connected to the lower end of the sealing cylinder. The acquisition circuit board also includes a memory for storing pore water pressure data detected by the pore water pressure gauge and acquired by the data acquisition device. The data output device is used to output the pore water pressure data stored in the memory. The pore water pressure gauge is connected to the lower end of the cable holder. The acquisition circuit board is installed inside the sealing cylinder, and a battery for powering the acquisition circuit board is provided inside the sealing cylinder. The wires of the acquisition circuit board pass through a through hole on the end of the sealing cylinder that connects to the cable holder and are then connected to the wires of the pore water pressure gauge. The wires of the acquisition circuit board are sealed together with the through hole. The connection point between the wires of the acquisition circuit board and the wires of the pore water pressure gauge is located inside the cable holder. The wires of the acquisition circuit board are sealed together with the through hole.

2. The pore water pressure gauge structure for measuring pore water pressure in the soil at the bottom of a foundation pit according to claim 1, characterized in that, The sealing cylinder includes a cylinder body, an upper end cover that is detachably and sealingly connected to the upper end of the cylinder body, and a lower end cover that is detachably and sealingly connected to the lower end of the cylinder body. The wire passage hole is provided on the lower end cover, and the wires of the acquisition circuit board are sealed and passed through the wire passage hole.

3. The pore water pressure gauge structure for measuring pore water pressure in the soil at the bottom of a foundation pit according to claim 2, characterized in that, The upper end cap is detachably inserted into the upper end of the cylinder. Several upper end cap fixing bolts pass through the cylinder and are threaded into the upper end cap threaded holes on the upper end cap. The upper end cap fixing bolts are distributed circumferentially along the cylinder. The lower end cap is detachably inserted into the lower end of the cylinder. Several lower end cap fixing bolts pass through the cylinder and are threaded into the lower end cap cylinder side threaded holes on the lower end cap. The lower end cap fixing bolts are distributed circumferentially along the cylinder.

4. The pore water pressure gauge structure for measuring pore water pressure in the soil at the bottom of a foundation pit according to claim 3, characterized in that, The upper end cover has two sealing grooves on its circumference where it is inserted into the cylinder. The upper end cover is fitted with two sealing rings located in the two sealing grooves, which seal the upper end cover to the cylinder. The lower end cover has two sealing grooves on its circumference where it is inserted into the cylinder. The lower end cover is fitted with two sealing rings located in the two sealing grooves, which seal the lower end cover to the cylinder.

5. A pore water pressure gauge structure for measuring pore water pressure in the soil at the bottom of a foundation pit, as described in claim 2, 3, or 4, characterized in that, The lower end of the wire-gathering seat is provided with an end wall, and the end wall is provided with a threaded hole. The pore water pressure gauge is provided with a threaded head, and the wire of the pore water pressure gauge is led out from the end face of the threaded head. The threaded head is threadedly connected to the threaded hole. The diameter of the part of the lower end cover that passes through the cylinder is smaller than the diameter of the lower end cover. The lower end cover is detachably inserted into the wire-gathering seat. Several wire-gathering seat fixing bolts pass through the wire-gathering seat and are threadedly connected to the lower end cover portion of the wire-gathering seat side threaded hole on the lower end cover.

6. A pore water pressure gauge structure for measuring pore water pressure in soil at the bottom of a foundation pit according to claim 1, 2, 3, or 4, characterized in that, The outer end face of the upper cover is provided with threaded holes for installing suspension wires.

7. A pore water pressure gauge structure for measuring pore water pressure in soil at the bottom of a foundation pit according to claim 1, 2, 3, or 4, characterized in that, The wires of the acquisition circuit board are connected to one end of the waterproof cable, and the waterproof cable is sealed in the wire hole. The wires of the pore water pressure gauge are connected to the other end of the waterproof cable. The wire hole is located at one end of the wire concentrator and has a large diameter section. An elastic sealing ring is installed in the large diameter section. The elastic sealing ring seals the waterproof cable to the wire hole. A step is formed between the large diameter section and the wire hole.

8. The pore water pressure gauge structure for measuring pore water pressure in the soil at the bottom of a foundation pit according to claim 7, characterized in that, The elastic sealing ring is sealed and fixed inside the wire hole by a sealing strip formed by adhesive.

9. The pore water pressure gauge structure for measuring pore water pressure in the soil at the bottom of a foundation pit according to claim 7, characterized in that, The threading hole is a straight hole. At one end of the large-diameter section, there is an annular blade extending circumferentially along the threading hole. The cross-section of the annular blade is triangular. The annular blade protrudes from the step. The inner circumferential surface of the annular blade and the circumferential surface of the threading hole are located on the same cylindrical surface. The cutting edge direction of the annular blade is the same as the center line direction of the threading hole. The surface of the waterproof cable is provided with an insulating plastic layer. The diameter of the waterproof cable is larger than the diameter of the threading hole.

10. The pore water pressure gauge structure for measuring pore water pressure in the soil at the bottom of a foundation pit according to claim 7, characterized in that, The conductive core of the waterproof cable has a wiring hole with a larger inner end and a smaller outer end on one end face of the wire base. The end of the wire of the pore water pressure gauge is knotted to form a clip that can pass through the wiring hole. The clip is inserted into the wiring hole, and the wiring hole is filled with conductive adhesive to form a clip head. The clip head bonds the wire of the pore water pressure gauge into the wire hole.

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