Hydraulic pushing penetration type layered soil pressure measuring device and method in drill hole

Abstract

The invention relates to the technical field of geotechnical engineering monitoring, in particular to a hydraulic pushing penetration type layered soil pressure measuring device and method.The device comprises a penetration structure, a fixing structure and an orifice positioning structure.The penetration structure comprises a fixing shell, an opening arc-shaped plate, a driving structure and a detecting structure; the detection structure comprises a soil pressure meter and a stay wire type displacement meter, the rotary multi-section oil cylinder is connected with the fixed shell, a built-in piston rod of the rotary multi-section oil cylinder penetrates through the open arc-shaped plate to be connected with the soil pressure meter, and a wire of the soil pressure meter is led out to the ground to be connected with a pressure data collector. According to the method, the soil pressure gauge is embedded into the undisturbed soil body by drilling and using the penetration structure, the upper surface and the lower surface of the soil pressure gauge can be in direct contact with the undisturbed soil body and directly reflect the stress change of the undisturbed soil body, and compared with a traditional method for hoisting the soil pressure gauge through drilling, the test accuracy can be greatly improved, and the method is more sensitive to the change of the pressure of the soil body.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical engineering monitoring, and particularly to a hydraulic jacking penetration type layered earth pressure measuring device and method in a borehole. Background Technique

[0002] The number of deep foundation pit projects in high-density urban areas and new construction projects adjacent to existing buildings has increased sharply. Under this background, how to accurately measure the three-dimensional distribution law of earth pressure around the deep foundation pit support system and adjacent structures through dynamic monitoring has become the core technical problem to ensure project stability and construction safety. As a key means, in-situ earth pressure measurement, its measurement accuracy and efficiency directly affect engineering safety decisions.

[0003] For example, CN108362419A discloses a device and method for measuring in-situ lateral earth pressure. When working, first drill a measurement hole to the required depth on the ground where the lateral earth pressure is to be measured, fix the positioning base on the ground, put the measurement pipe into the measurement hole, and fix and position the measurement pipe at the top through an adjustable clamp; send a power-off instruction through the control box to control the electromagnetic characteristics of the electromagnetic ball. At this time, the whole airbag is in a slidable state. Shake the crank, and the fixed pulley drives the rope tied to the airbag to slowly fall until it reaches the designated position in the measurement hole. The control box sends a power-on instruction, and the electromagnetic ball locks on the internal guide rail of the measurement pipe, and the airbag is exposed at the lower end of the measurement pipe; the control box controls the gas storage tank to inflate the airbag through the air duct. The air guiding device in the airbag can guide the gas to fill evenly, so that the airbag expands; through the calculation of the control box, control the size of the gas volume, so that when the airbag expands to the diameter of the original measurement hole, record and store the stress-strain signal fed back by the strain sensor due to contact and extrusion of the soil body; continue to inflate the airbag until the airbag expands to a certain value larger than the diameter of the measurement hole, record the stress-strain signal value during the whole expansion process, and after calculation by the control box, convert it into a stress-strain curve. Utilize the characteristic of uniform pressurization and expansion of the airbag to make the obtained value closer to the real value. However, after the drilling operation of this device, the soil near the hole wall is uneven after being cut by the drill bit and the hole wall is arc-shaped, resulting in stress concentration when the surface of the strain sensor contacts the hole wall, and it cannot truly reflect the lateral earth pressure data; in addition, this device does not have the function of measuring vertical earth pressure, and due to the air leakage problem of the airbag during long-term operation, it cannot achieve long-term stable operation.

[0004] In addition, the existing methods have significant defects: specifically, (1) in the drilling and hoisting method, after hoisting the earth pressure cell through a drilled hole with a diameter of 250-300 mm and then backfilling in layers, since the backfilled soil and the undisturbed soil form a discontinuous force transmission interface, when the formation stress is redistributed, the stress wave is abnormally attenuated and the measured value is seriously distorted. Moreover, as the drilling depth increases, the soil arch effect caused by the backfilled soil column will exacerbate the secondary interference of the vertical stress transmission, forming a systematic deviation; (2) in the artificial exploratory shaft method, a large-diameter exploratory shaft with a diameter of 600-800 mm is used to slot the hole wall for embedding. Not only does the mechanical slotting lead to poor contact between the earth pressure cell and the undisturbed soil, but also the large-diameter drilled hole causes a severe disturbance to the initial stress field of the formation, forming a new stress field, resulting in a significant reduction in the credibility of the test data. In addition, the construction period of this method is as long as several weeks and requires personnel to work underground, with risks of falling from height and collapse, and both safety and efficiency are limited. The above methods generally have deficiencies such as poor accuracy, unclear earth pressure force transmission path, gaps between the earth pressure cell and the undisturbed soil mass, and low test efficiency.

[0005] There is an urgent need to develop a multi-depth and high-precision earth pressure synchronous monitoring device and test method that can achieve close contact between the earth pressure cell and the undisturbed soil in a small-diameter drilled hole, so as to improve the accuracy and test efficiency of in-situ earth pressure testing and provide technical support for the accurate monitoring of the earth pressure field under complex geological conditions. Summary of the Invention

[0006] Aiming at the problem of how to improve the accuracy and efficiency of in-situ earth pressure testing in a small-diameter drilled hole in the prior art, the present invention provides a hydraulic jacking penetration type layered earth pressure measuring device and method in a drilled hole, which can install the earth pressure cell into the internal soil to be monitored at different depths in the same small-diameter drilled hole, realize the automatic monitoring of the distribution of vertical or horizontal earth pressure along the soil layer depth direction, shorten the installation time, and reduce the influence of the drilled hole on the surrounding stress field. The device is reasonably designed, easy to operate and has good use effects.

[0007] The present invention is realized through the following technical solutions: A hydraulic jacking penetration type layered earth pressure measuring device in a borehole, comprising a penetration structure, a fixing structure and a hole orifice positioning structure. The fixing structure includes an operating rod, a connecting head and a U-shaped rod connected in sequence from top to bottom. The operating rod is connected to the hole orifice positioning structure, and the U-shaped rod is connected to the fixed shell of the penetration structure. The penetration structure includes a fixed shell, an open arc plate, a driving structure and a detection structure. The fixed shell and the open arc plate are symmetrically arranged left and right. The driving structure includes a cylinder structure and a rotary multi-stage oil cylinder. The fixed end of the cylinder structure is installed in the fixed shell, and the movable end is connected to the open arc plate. The detection structure includes an earth pressure gauge and a wire-pulling displacement gauge. The rotary multi-stage oil cylinder is connected to the fixed shell. The built-in piston rod of the rotary multi-stage oil cylinder penetrates through the open arc plate and is connected to the earth pressure gauge. The wire of the earth pressure gauge is led out to the ground and connected to a pressure data collector. The cylinder structure and the rotary multi-stage oil cylinder perform telescopic movements in the same direction.

[0008] Preferably, the hole orifice positioning structure includes a positioning ring, a fixing frame and a swinging bolt. The fixing frame is installed inside the positioning ring. The operating rod penetrates through the center of the fixing frame and is connected to the swinging bolt. The swinging bolt is movably installed on the fixing frame.

[0009] Preferably, a non-through groove is provided at the upper part of the center of the fixing frame, and the swinging bolt is inserted into the non-through groove.

[0010] Preferably, the cross-section of the non-through groove is arc-shaped, and the bottom of the swinging bolt is arc-shaped to match the arc-shaped non-through groove. A through groove is provided at the lower part of the center of the fixing frame. The length axis of the through groove is perpendicular to the length axis of the non-through groove. The operating rod passes through the through groove and is connected to the swinging bolt.

[0011] Preferably, the fixed shell includes an upper fixed platform and a lower fixed platform. The upper fixed platform and the lower fixed platform are respectively detachably connected to the top and bottom of the shell of the rotary multi-stage oil cylinder. The cylinder structure includes parallel first and second cylinders. The first cylinder is installed in the upper fixed platform, and the second cylinder is installed in the lower fixed platform. The first cylinder and the second cylinder are connected to an adjustable air pressure control console through a gas pipeline. The rotary multi-stage oil cylinder is led out to the ground through a liquid pipeline.

[0012] Preferably, a wire-pulling displacement gauge is provided in the lower fixed platform, and the cable of the wire-pulling displacement gauge is led out to the ground.

[0013] Preferably, the open arc plate is circular arc-shaped, and a through cooperation groove is provided on the open arc plate. The cooperation groove includes a vertically connected vertical groove and a horizontal groove, and the cooperation groove cooperates with a push head.

[0014] Preferably, a push head is provided between the built-in piston rod of the rotary multi-section oil cylinder and the earth pressure gauge; the push head includes a connected bottom plate and an expansion head. The rear end of the bottom plate is fixedly connected to the piston of the rotary multi-section oil cylinder. A protruding rod is provided at the bottom end of the bottom plate, and the protruding rod is inserted into the pulling head of the wire-pulling type displacement gauge. The expansion head is located at the front end of the bottom plate, and the front end of the expansion head is connected to the earth pressure gauge loader through a plurality of insertion rods, and the earth pressure gauge is installed on the earth pressure gauge loader.

[0015] Preferably, the front end of the earth pressure gauge loader is conical, the rear end is arc-shaped, and the front end of the expansion head is arc-shaped and matches the rear end of the earth pressure gauge loader.

[0016] A method for measuring layered earth pressure by hydraulic jacking penetration in a borehole, using the above-mentioned device for measuring layered earth pressure by hydraulic jacking penetration in a borehole, the specific steps are as follows: S1, borehole drilling; S2, assemble the penetration structure on the ground; S3, install the orifice positioning structure, penetration structure and fixing structure in the borehole; S4, borehole backfilling; S5, data acquisition and processing.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The penetration structure, fixing structure and orifice positioning structure adopted by the device for measuring layered earth pressure by hydraulic jacking penetration in a borehole of the present invention realize low-cost and convenient pressure measurement. By drilling a borehole and using the penetration structure to embed the earth pressure gauge into the undisturbed soil mass, the upper and lower surfaces of the earth pressure gauge can directly contact the undisturbed soil mass, directly reflecting the stress change of the undisturbed soil. Compared with the traditional method of suspending the earth pressure gauge by drilling, the test accuracy can be greatly improved, it is more sensitive to the change of soil pressure, and multiple earth pressure gauges can be longitudinally inserted at different depths in the same small-diameter borehole without drilling multiple boreholes along the circumferential direction on the ground, greatly saving manpower and material resources, and greatly reducing the installation and test time of the earth pressure gauge.

[0018] A wire-pulling type displacement gauge is arranged in the penetration structure to monitor the distance that the earth pressure gauge loader embeds into the soil during the penetration process, which can ensure that the earth pressure gauge loader is integrally inserted into the soil on the side wall of the borehole, prevent the insufficient insertion depth of the earth pressure gauge loader from affecting the monitoring data of the earth pressure gauge, avoid the earth pressure gauge from falling or shifting during the subsequent backfilling process, and at the same time prevent the over-push of the penetration structure from damaging the external waterproof shell of the rotary multi-section oil cylinder and the earth pressure gauge and damaging the internal electronic devices.

[0019] An opening arc-shaped plate is arranged on the front side of the penetration structure. During the penetration process, if one side of the opening arc-shaped plate contacts the side wall of the drilling hole first, the back sides of the upper fixed platform, the rotating multi-section oil cylinder and the lower fixed platform can be contacted and embedded into the side wall of the drilling hole through the interaction force, so that the whole penetration structure is kept vertical, avoiding angular displacement of the penetration structure during the penetration of the earth pressure gauge, resulting in deviation of the position where the earth pressure gauge is inserted into the soil body. Moreover, during the penetration process, the earth pressure gauge loader is restricted by the notch of the opening arc-shaped plate and the propelling rod, ensuring that the earth pressure gauge is always inserted into the side wall of the drilling hole in a horizontal state.

[0020] By rotating the multi-section pistons of the rotating multi-section oil cylinder and arranging a matching groove on the opening arc-shaped plate, the horizontal earth pressure can be monitored, and it can be changed at any time according to the actual monitoring requirements.

[0021] All parts can be detachably connected, which is convenient for carrying. If any part is damaged, it can be detachably replaced and continue to be used. If the models of the earth pressure gauges are different, only the earth pressure gauge loader needs to be replaced to use, which is convenient, fast, time-saving and labor-saving. Description of the Drawings

[0022] Figure 1 It is the overall schematic diagram of the penetration structure and the fixed structure in a kind of hydraulic jacking penetration type layered earth pressure measuring device in the borehole of the present invention; Figure 2 It is the overall schematic diagram of the penetration structure and the fixed structure in another state of a kind of hydraulic jacking penetration type layered earth pressure measuring device in the borehole of the present invention; Figure 3 It is the assembly schematic diagram of the penetration structure and the fixed structure in the present invention; Figure 4 It is the schematic diagram of the rotating multi-section oil cylinder in the present invention; Figure 5 It is the schematic diagram of the upper fixed platform in the present invention; Figure 6 It is the schematic diagram of the lower fixed platform in the present invention; Figure 7 It is the schematic diagram of the opening arc-shaped plate in the present invention; Figure 8 It is the schematic diagram of the propulsion head in the present invention; Figure 9 It is the schematic diagram of the earth pressure gauge loader in the present invention; Figure 10 It is the schematic diagram of the fixed structure in the present invention; Figure 11 It is the overall schematic diagram of the hole orifice positioning structure in the present invention; Figure 12 It is the disassembled schematic diagram of the hole orifice positioning structure in the present invention; Figure 13It is a schematic diagram of the construction status of the installation process of the earth pressure gauge in the present invention; Figure 14 It is a schematic diagram of the state of data monitoring after the soil pressure gauge in the present invention is installed; Figure 15 The present invention is a flowchart of a method for measuring layered earth pressure by hydraulic jacking penetration in a borehole.

[0023] In the figure: 1, rotating multi-section oil cylinder; 1-1, top oil pipe; 1-2, recovery oil pipe; 1-3, fixed tooth; 1-4, first threaded hole; 1-5, second threaded hole; 1-6, multi-section piston; 1-7, third threaded hole; 2, upper fixed platform; 2-1, pressure relief hole; 2-2, first cylinder; 2-3, first top air outlet pipe; 2-4, first recovery air pipe; 2-5, first cushion block; 2-6, fourth threaded hole; 2-7, oil hole; 3, lower fixed platform; 3-1, second cylinder; 3-2, second top air outlet pipe; 3-3, second recovery air pipe; 3-4, second cushion block; 3-5, fifth threaded hole; 3-6, wire-pulling displacement meter; 3-7, first cable; 3-8, pull head; 4, open arc plate; 4-1, third cushion block; 4-2, fourth cushion block; 4-3, sixth threaded hole; 4-4, matching groove; 4-5, first wire groove; 5, push head; 5-1, bottom plate; 5-2, extension head; 5-3, countersunk threaded hole; 5-4, second wire groove ; 5-5, plug rod; 5-6, protruding rod; 6, soil pressure gauge loader; 6-1, soil pressure gauge reserved hole; 6-2, plug hole; 6-3, third wire groove; 7, soil pressure gauge; 7-1, wire; 8, fixing structure; 8-1, operating rod; 8-2, connector; 8-3, U-shaped rod; 8-4, seventh threaded hole; 8-5, pin shaft; 9, hole positioning structure; 9-1, positioning ring; 9-2, fixing frame; 9-3, swing pin; 9-4, fixing groove; 9-5, anchoring tooth; 10, pneumatic control console; 11, pressure data collector; 12, displacement data collector; 13, double-acting hydraulic pump station; 14, ground; 15, drilling; 16, original soil; 17, backfill soil. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0025] The present invention discloses a hydraulic jacking penetration type layered soil pressure measuring device in a borehole, referring to Figure 1 , 2 , 3, including penetration structure, fixing structure and orifice positioning structure, among which Figure 1 To test and install the penetration structure under vertical earth pressure, Figure 2For testing and installing the penetration structure during horizontal earth pressure measurement, the penetration structure is connected and fixed to the fixed structure by bolts, connected to the hole opening through an operating rod, and connected and fixed to the hole opening positioning structure located at the hole opening through a pin shaft.

[0026] The penetration structure includes a rotary multi-stage oil cylinder 1, an upper fixed platform 2, a lower fixed platform 3, an open arc plate 4, a pushing head 5, an earth pressure gauge loader 6, and an earth pressure gauge 7; the rotary multi-stage oil cylinder 1, the upper fixed platform 2, and the lower fixed platform 3 are connected into an integral body by bolts, and the overall height is , preferably controlled at about 300 mm.

[0027] The back side of the rotary multi-stage oil cylinder 1 is cylindrical, with the same diameter as the diameter of the borehole 15, and is provided with a number of fixing teeth 1-3 for increasing the friction between the back side of the rotary multi-stage oil cylinder 1 and the soil body on the side wall of the borehole 15, preventing the rotary multi-stage oil cylinder 1 from sliding during the penetration of the earth pressure gauge 7, and ensuring the horizontal penetration of the earth pressure gauge 7 into the internal soil body to be monitored; the rotary multi-stage oil cylinder 1 contains multiple piston sections 1-6, and can be jacked out and recovered through a double-acting hydraulic pump station 13.

[0028] A number of third threaded holes 1-7 are opened on the outermost side of the multiple piston sections 1-6 for bolt connection of the pushing head 5 to fix the pushing head 5 to the rotary multi-stage oil cylinder 1.

[0029] A number of first threaded holes 1-5 are opened on the front side of the rotary multi-stage oil cylinder 1 for bolt connection to the fixed structure 8; a number of second threaded holes 1-4 are opened on the top of the rotary multi-stage oil cylinder 1 for bolt connection to the upper fixed platform 2 to make the two into an integral body. The top side of the rotary multi-stage oil cylinder 1 is connected to the jacking oil pipe 1-1 and the recovery oil pipe 1-2 to realize pressurization and depressurization of the rotary multi-stage oil cylinder 1, and to push the built-in piston 1-6 of the rotary multi-stage oil cylinder 1 to jack out and recover; a number of second threaded holes 1-4 are opened on the bottom side of the rotary multi-stage oil cylinder 1 for bolt connection to the lower fixed platform 3 to make the two into an integral body.

[0030] A number of fourth threaded holes 2-6 are opened on the bottom side of the upper fixed platform 2 and are bolted and fixed to the upper side of the rotary multi-stage oil cylinder 1. The back side is provided with a number of fixing teeth 1-3 and a number of pressure relief holes 2-1, and the pressure relief holes 2-1 are used to reduce the interfacial adsorption force between the upper fixed platform 2 and the soil body on the side wall of the borehole 15 during the penetration process.

[0031] A first cushion block 2-5 is provided inside the upper fixed platform 2, and a first air cylinder 2-2 is bolted and fixed. The top side of the first air cylinder 2-2 is connected to the first jacking air pipe 2-3 and the first recovery air pipe 2-4. By adjusting the pressurization and depressurization of the first air cylinder 2-2 through the air pressure control console 10, the jacking out and recovery of the first air cylinder 2-2 are realized.

[0032] The upper fixed platform 2 reserves an oil hole 2-7 at the bottom side, which is used to extend the ejection oil pipe 1-1 and the recovery oil pipe 1-2 of the rotary multi-joint oil cylinder 1 to the ground 14 through the reserved oil hole 2-7.

[0033] The internal structure of the lower fixed platform 3 is basically the same as that of the upper fixed platform 2. The difference is that the lower fixed platform 3 is provided with a wire-pulling type displacement gauge 3-6, and the first cable 3-7 of the wire-pulling type displacement gauge 3-6 is led to the ground 14 and connected to the displacement data collector 12, which is used to monitor the distance of the earth pressure gauge 7 embedded in the soil mass during the penetration process of the earth pressure gauge 7 in real time.

[0034] The opening arc plate 4 is a circular arc-shaped thin-walled light alloy plate, and the overall height should be the same as the overall height h formed by the upper fixed platform 2, the rotary multi-joint oil cylinder 1 and the lower fixed platform 3. A number of pressure relief holes 2-1 are opened through the opening arc plate 4, which is used to reduce the interface adsorption force between the opening arc plate 4 and the soil mass on the side wall of the drill hole 15 during the penetration process; a number of fixed teeth 1-3 are arranged on the front side of the opening arc plate 4, which is used to increase the friction between the front side of the opening arc plate 4 and the soil mass on the side wall of the drill hole 15, prevent the opening arc plate 4 from sliding during the penetration process of the earth pressure gauge 7, and ensure that the earth pressure gauge 7 horizontally penetrates into the soil mass to be monitored; the opening arc plate 4 is provided with a third cushion block 4-1 and a fourth cushion block 4-2, and a number of sixth threaded holes 4-3 are opened through the third cushion block 4-1 and the fourth cushion block 4-2, which are used for bolt connection and fixation of the first air cylinder 2-2 and the second air cylinder 3-1; a mating groove 4-4 is opened in the middle of the opening arc plate 4, and the mating groove 4-4 contains a notch slightly larger than the pushing head 5 and the earth pressure gauge loader 6, which is used to ensure that the earth pressure gauge 7 is horizontal as a whole during the penetration process of the earth pressure gauge 7; a wire groove 4-5 is opened on the front side of the opening arc plate 4, which is used to extend the earth pressure gauge wire 7-1 to the ground 14, and when the opening arc plate 4 is recovered, the earth pressure gauge wire 7-1 can freely exit from the first wire groove 4-5.

[0035] The pushing head 5 includes a bottom plate 5-1 and an expansion head 5-2; a number of countersunk threaded holes 5-3 are opened on the bottom plate 5-1, and are connected and fixed to the piston 1-6 of the rotary multi-joint oil cylinder 1 through countersunk bolts; a second wire groove 5-4 is opened on the bottom plate 5-1, and the wire 7-1 of the earth pressure gauge 7 extends out through the second wire groove 5-4 and is led to the ground 14; a protruding rod 5-6 is arranged at the bottom end of the bottom plate 5-1, which can be inserted into the pull head 3-8 of the wire-pulling type displacement gauge 3-6, and is used to drive the wire-pulling type displacement gauge 3-6 during the penetration process of the earth pressure gauge 7 to monitor the penetration distance of the earth pressure gauge 7.

[0036] The front end of the expansion head 5-2 is arc-shaped, and its diameter is the same as the diameter of the drill hole 15. A second wire groove 5-4 is opened in the middle of the expansion head 5-2; the expansion head 5-2 is provided with a number of insertion rods 5-5, which can be inserted into the jacks 6-2 at the rear side of the earth pressure gauge loader 6.

[0037] The front end of the earth pressure gauge loader 6 is conical, which reduces the resistance of the soil to the earth pressure gauge loader 6 during the penetration process of the earth pressure gauge 7; the rear side of the earth pressure gauge loader 6 is arc-shaped, and its diameter is the same as that of the borehole 15, ensuring that the earth pressure gauge loader 6 can be completely penetrated into the sidewall soil of the borehole 15.

[0038] A reserved hole 6-1 for the earth pressure gauge is provided at the center of the earth pressure gauge loader 6 for embedding and fixing the earth pressure gauge 7, which can reduce the radial load parallel to the surface of the earth pressure gauge 7 during the penetration process and prevent the radial load on the earth pressure gauge 7 from being too large, affecting the measurement accuracy of the axial earth pressure perpendicular to the surface of the earth pressure gauge 7.

[0039] A jack 6-2 is provided at the rear side of the earth pressure gauge loader 6, and the insertion rod 5-5 of the pushing head 5 can be inserted into the jack 6-2 to temporarily fix the earth pressure gauge loader 6, ensuring that the earth pressure gauge 7 always remains horizontal during the penetration process, and when the multi-section piston 1-6 is retracted, the insertion rod 5-5 can freely withdraw from the jack 6-2; a third wire groove 6-3 is provided at the rear end of the earth pressure gauge loader 6, and the wire 7-1 of the earth pressure gauge 7 can extend through the third wire groove 6-3 and be led to the ground 14.

[0040] The earth pressure gauge 7 is a solid cylinder pressure sensor, and a wire 7-1 extends from the side for connecting to the pressure data collector 11 on the ground 14 to collect the earth pressure change data in the formation in real time.

[0041] The fixing structure 8 includes an operating rod 8-1, a connecting head 8-2 and a U-shaped rod 8-3.

[0042] The operating rod 8-1 is a cylindrical segmented connecting rod, and the operating rods 8-1 can be connected end to end, and the assembly and disassembly with the connecting head 8-2 are realized by inserting a pin shaft 8-5.

[0043] An axial groove is provided at the top of the connecting head 8-2 and is fixedly connected to the operating rod 8-1 through a pin shaft 8-5; an axial internal threaded hole is provided at the bottom of the connecting head 8-2 for fixedly connecting with the U-shaped rod 8-3 as a whole.

[0044] A threaded rod is provided at the top of the U-shaped rod 8-3, and the threaded rod has an external thread for bolt connection and fixing to the connecting head 8-2. A number of seventh threaded holes 8-4 are provided through the U-shaped rod 8-3 for bolt connection and fixing to the front side of the rotary multi-section oil cylinder 1.

[0045] The orifice positioning structure 9 includes a positioning ring 9-1, a fixing frame 9-2 and a swinging pin 9-3.

[0046] The positioning ring 9-1 is placed at the orifice of the drill hole 15 for positioning the center position of the drill hole 15. A number of fixing grooves 9-4 are provided on the positioning ring 9-1 for fixing and determining the position of the fixing frame 9-2, so that the center of the fixing frame 9-2 is located at the center of the orifice of the drill hole 15. A number of anchoring teeth 9-5 are provided at the bottom of the positioning ring 9-1 for fixing the positioning ring 9-1 at the orifice of the drill hole 15. The fixing frame 9-2 is placed in the fixing groove 9-4 of the positioning ring 9-1.

[0047] A non-through groove is provided at the center of the fixing frame 9-2 for inserting and fixing the swing pin 9-3.

[0048] A through groove is provided at the bottom of the fixing frame 9-2 to allow the swing pin 9-3 to rotate at a fixed angle.

[0049] The swing pin 9-3 is placed in the groove of the fixing frame 9-2, allowing the swing pin 9-3 to rotate at a fixed angle when the operating rod 8-1 is tilted, preventing stress concentration inside the operating rod 8-1. The swing pin 9-3 is connected to the operating rod 8-1 through a pin shaft 8-5.

[0050] There are differences in the shape of the pushing head 5 and the grooving shape of the opening arc plate 4 between the penetration structure for installing the vertical earth pressure gauge 7 and the penetration structure for installing the horizontal earth pressure gauge 7, and the rest of the structures are the same.

[0051] Multi-stage oil cylinders are preferably double-acting oil cylinders, or single-acting oil cylinders with internal rigid springs can also be used to realize the ejection and recovery of the piston.

[0052] The wire-pulling type displacement gauge 3-6 can be replaced with displacement sensors such as a thimble type displacement gauge and a laser displacement gauge to monitor the distance of the earth pressure gauge 7 embedded in the soil during the penetration process in real time.

[0053] The operating rod 8-1 is preferably a thin-walled hollow lightweight alloy rod to improve the bending stiffness of the operating rod 8-1 and reduce the overall weight of the device.

[0054] One end of the operating rod 8-1 can be a threaded rod and the other end can be an axially internal threaded hole, and adjacent operating rods 8-1 can be connected by threads to realize assembly and disassembly.

[0055] The pin shaft 8-5 can be replaced with other fixed connection pin shafts for temporarily fixing adjacent operating rods 8-1.

[0056] As Figure 14 shown, the present invention also discloses a method for measuring the layered earth pressure by hydraulic jacking penetration in a drill hole, and the steps are simple, including the following steps: Step 1: Drill hole drilling Step 101: Determine the measuring point coordinates according to the monitoring plan, and use a drill rig to drill a vertical hole at the predetermined position; Step 102: Control the diameter of the drill hole 15 within 130 mm to avoid disturbing the stress field of the surrounding soil mass. Step 103: Pause when drilling to about h / 2 below the bottom monitoring point, and collect undisturbed soil samples at this depth for geotechnical tests.

[0057] During the drilling process, undisturbed soil samples at each monitoring depth need to be retained for subsequent geotechnical tests to understand the initial physical and mechanical indexes of the soil at each monitoring point. The diameter of the drill hole is 130 mm. The diameter of the drill hole should not be too large, otherwise the drill hole will have too much influence on the initial stress field of the surrounding soil mass and affect the measurement accuracy.

[0058] Step Two: Pre-assemble the soil pressure gauge penetration structure on the ground Step 201: Connect and fix the upper fixed platform 2, the lower fixed platform 3 and the rotary multi-section oil cylinder 1 with bolts. Connect the first cylinder 2-2 and the second cylinder 3-1 with bolts to fix the first cushion block 2-5 and the second cushion block 3-4 on the upper fixed platform 2 and the lower fixed platform 3. Step 202: Connect and fix the wire-pulling displacement gauge 3-6 to the lower fixed platform 3. Fix the connecting head 8-2 to the U-shaped rod 8-3 with bolts, and fix the U-shaped rod 8-3 to the rotary multi-section oil cylinder 1. Fix the pushing head 5 to the multi-section piston 1-6. Step 203: Connect the first air ejection pipe 2-3 and the first air recovery pipe 2-4 to the first cylinder 2-2, and connect the second air ejection pipe 3-2 and the second air recovery pipe 3-3 to the second cylinder 3-1. According to the requirements of vertical or horizontal soil pressure monitoring, select the soil pressure gauge notch 4-4 of the open arc plate 4 to be vertical or horizontal, and connect and fix the open arc plate 4 to the first cylinder 2-2, the second cylinder 3-1, the third cushion block 4-1 and the fourth cushion block 4-2 with bolts. Step 204: Fix the soil pressure gauge 7 to the soil pressure gauge loader 6 with strong glue. Insert the insertion rod 5-5 of the pushing head 5 into the jack 6-2 of the soil pressure gauge loader 6, pass the soil pressure gauge loader 6 through and fix it inside the groove 4-4 of the open arc plate 4. Extend the soil pressure gauge wire 7-1 out of the ground 14 from the first wire groove 4-5 opened on the open arc plate 4. The assembly of the soil pressure gauge 7 penetration structure is completed.

[0059] Step Three: Installation of the soil pressure gauge Step 301: Place the positioning ring 9-1 of the orifice positioning structure 9 at the orifice of the drill hole 15 to ensure that the positioning ring 9-1 coincides with the center of the drill hole 15. Step 302: Temporarily fix the operating rod 8-1 and the connector 8-2 by connecting them with a pin shaft 8-5. The operator on the ground 14 lowers the penetration structure into the borehole 15 by continuously connecting the operating rod 8-1. Every time it is lowered by a certain distance, steel hose clamps are used to fix the ejection oil pipe 1-1, the recovery oil pipe 1-2, the first ejection air pipe 2-3, the second ejection air pipe 3-2, the first recovery air pipe 2-4, the second recovery air pipe 3-3, the first cable 3-7 of the wire-drawing displacement gauge, and the soil pressure gauge wire 7-1. When it is lowered to the bottom of the borehole 15, stop lowering. Place the fixing frame 9-2 into the fixing groove 9-4 of the positioning ring 9-1. Connect the bottom end of the swing pin 9-3 and the operating rod 8-1 with a pin shaft 8-5, and insert the swing pin 9-3 into the groove in the center of the fixing frame 9-2 to fix the penetration structure at the specified depth; Step 303: Connect the first ejection air pipe 2-3 and the second ejection air pipe 3-2 to the air pressure control console 10, adjust the pressure of the air pressure control console 10, simultaneously pressurize the first cylinder 2-2 and the second cylinder 3-1, push the opening arc plate 4 to make it close to the side wall of the borehole 15, and at the same time push the upper fixing platform 2, the rotary multi-joint oil cylinder 1, and the lower fixing platform 3 of the penetration structure in the opposite direction, and embed the fixing teeth 1-3 at the rear of the three into the hole wall and closely fit them with the side wall of the borehole 15; Step 304: Connect the ejection oil pipe 1-1 and the recovery oil pipe 1-2 of the rotary multi-joint oil cylinder 1 to the double-acting hydraulic pump station 13 through quick connectors. Adjust the double-acting hydraulic pump station 13 to supply oil and pressurize the ejection oil pipe 1-1, eject the multi-joint piston 1-6 of the rotary multi-joint oil cylinder 1, and push the soil pressure gauge loader 6 and the soil pressure gauge 7 into the soil body on the side wall of the borehole 15. At the same time, observe the displacement value of the wire-drawing displacement gauge 3-6 in real time. When the displacement value increment reaches the predetermined value, that is, when the soil pressure gauge loader 6 carries the soil pressure gauge 7 completely into the soil body on the side wall of the borehole 15, stop supplying oil and pressurizing the ejection oil pipe 1-1. At this time, the soil pressure gauge 7 is embedded into the soil body at the predetermined monitoring depth; Step 305: Adjust the double-acting hydraulic pump station 13 to pressurize the recovery oil pipe 1-2, gradually retract the multi-joint piston 1-6 of the rotary multi-joint oil cylinder 1. At this time, the insertion rod 5-5 of the pushing head 5 withdraws from the insertion hole 6-2 of the soil pressure gauge loader 6, separates the pushing head 5 from the soil pressure gauge loader 6, and then adjusts the air pressure control console 10 to pressurize the first recovery air pipe 2-4 and the second recovery air pipe 3-3, and retract the opening arc plate 4 to the initial position. At this time, the soil pressure gauge wire 7-1 withdraws from the first wire groove 4-5 of the opening arc plate 4; Step 306: Lift the operating rod 8-1 and remove the steel hose clamp, lift the penetration structure to the ground 14, fix the next soil pressure gauge 7 to the soil pressure gauge loader 6 according to Step 204, and place it into the penetration structure; Step 307: Repeat steps 302, 303, 304, 305, 306, and 307 until all earth pressure gauges 7 are installed.

[0060] Step Four: Borehole Backfilling Backfill the borehole 15 layer by layer, compacting each 30 cm layer to the elevation of the existing ground surface 14 to ensure that the density of the backfill soil 17 after compaction is basically the same as the density of the soil around the borehole 15.

[0061] Step Five: Data Acquisition and Processing Step 501: Connect the wires 7-1 of all earth pressure gauges 7 to the pressure data collector 11 to continuously monitor the vertical or horizontal earth pressure distribution of the soil at different depths; Step 502: Process the collected earth pressure data. The processing method is as follows: Perform zero calibration before the earth pressure gauge is inserted, and measure the initial value of the earth pressure gauge in the free state E 0‌ , when the borehole is backfilled to the ground surface 14 after the earth pressure gauge is inserted, measure the initial value of the earth pressure gauge E 1, record the real-time monitoring value of the earth pressure gauge during the construction process ‌E t ‌, then the true change in the earth pressure gauge △ E = E t - E 1, if it is necessary to further calibrate the zero drift of the earth pressure gauge 7, then the measured value of the earth pressure gauge 7 after correction should be: E = E t - E 0.

[0062] In this embodiment, the dimensions of the outer fixing teeth 1-3 of the upper fixing platform 2, the lower fixing platform 3, and the opening arc plate 4 should be not more than 2 mm, which can reduce the influence on the borehole wall of the borehole 15 while fixing the penetration structure.

[0063] In this embodiment, the upper fixing platform 2 and the lower fixing platform 3 should preferably be made of stainless steel to prevent equipment corrosion during the long-term construction process, and at the same time ensure that the fixing platform has a certain anti-deformation ability to provide sufficient reaction force during the installation of the earth pressure gauge 7 in the penetration structure.

[0064] In this embodiment, the rotary multi-stage oil cylinder 1, the upper fixing platform 2, and the lower fixing platform 3 should preferably be made of stainless steel, and the opening arc plate 4 can be made of aluminum alloy to reduce the resistance during the extension and retraction of the first cylinder 2-2 and the second cylinder 3-1.

[0065] In this embodiment, the rotary multi-stage oil cylinder 1 is preferably a double-acting oil cylinder, or a single-acting oil cylinder with a built-in rigid spring can also be used to realize the ejection and recovery of the piston; In this embodiment, the first cylinder 2-2 and the second cylinder 3-1 can be replaced by an electric push-pull rod, and the ejection and recovery of the opening arc plate 4 are realized by being powered on through an external power supply; In this embodiment, the range of the wire displacement gauge 3-6 should be greater than half of the diameter of the drill hole 15.

[0066] In this embodiment, the diameter of the drill hole 15 in step two is preferably not greater than 130 mm.

[0067] For the hydraulic jacking and penetration type layered earth pressure measuring device in a drill hole of the present invention, when installing the earth pressure gauge 7, there is no need for personnel to enter the inside of the drill hole 15, and all installation work is completed above the ground 14, avoiding the cumbersome steps of the traditional method of drilling large-diameter exploration wells manually and installing them underground, being safe and reliable and having higher installation accuracy.

[0068] The diameter of the drilled exploration hole can be less than 130 mm. Compared with the traditional method of drilling a 600-mm artificial exploration well, it can greatly reduce the interference with the initial stress field of the surrounding soil mass and improve the measurement accuracy.

[0069] Fixed teeth 1-3 are provided on the outer sides of the upper fixed platform 2, the rotary multi-stage oil cylinder 1, the lower fixed platform 3 and the opening arc plate 4. During the penetration process, the fixed teeth 1-3 can be embedded in the soil mass on the side wall of the drill hole 15 to prevent the penetration structure from sliding up and down and ensure the stability of the penetration process; at the same time, the upper fixed platform 2, the lower fixed platform 3 and the opening arc plate 4 are provided with through pressure relief holes 2-1, which can reduce the interfacial adsorption force generated by the extrusion of the penetration structure and the side wall of the drill hole 15 and ensure the smooth retraction of the opening arc plate 4.

[0070] All the parts and equipment of the penetration structure are waterproof and can be used for the earth pressure monitoring work under the condition of a relatively high groundwater level. Each part can be detachably connected, which is convenient to carry. If any part is damaged, it can be disassembled and replaced and then continue to be used. If the model of the earth pressure gauge 7 is different, only the loader 6 of the earth pressure gauge 7 needs to be replaced to be used, which is convenient, fast, time-saving and labor-saving.

[0071] In summary, the hydraulic jacking and penetration type layered earth pressure measuring device in a drill hole of the present invention is reasonably designed, has a low input cost, saves manpower and material resources, and is convenient to install and operate. It can be used to install the earth pressure gauge 7 into the internal soil mass to be monitored at different depths in the same small-diameter drill hole 15, realize the automatic monitoring of the distribution of vertical or horizontal earth pressure along the soil layer depth direction, shorten the installation time, and reduce the influence of the drill hole 15 on the surrounding stress field.

[0072] The above are only the preferred embodiments of the present invention and are not intended to limit the technical solutions of the present invention. Those skilled in the art should understand that without departing from the spirit and principle of the present invention, the technical solutions can be subject to several simple modifications and substitutions, and these modifications and substitutions also fall within the protection scope covered by the claims.

Claims

1. A hydraulic jacking penetration type layered earth pressure measuring device inside a borehole, characterized in that, It includes a penetration structure, a fixing structure and an orifice positioning structure. The fixing structure includes an operating rod (8-1), a connecting head (8-2) and a U-shaped rod (8-3) connected in sequence from top to bottom. The operating rod (8-1) is connected to the orifice positioning structure, and the U-shaped rod (8-3) is connected to the fixed housing of the penetration structure; the penetration structure includes a fixed housing, an open arc plate (4), a driving structure and a detection structure. The fixed housing and the open arc plate (4) are symmetrically arranged left and right. The driving structure includes a cylinder structure and a rotating multi-stage oil cylinder (1). The fixed end of the cylinder structure is installed in the fixed housing, and the movable end is connected to the open arc plate (4); the detection structure includes an earth pressure gauge (7) and a wire-type displacement gauge (3-6). The rotating multi-stage oil cylinder (1) is connected to the fixed housing. The built-in piston rod of the rotating multi-stage oil cylinder (1) penetrates through the open arc plate (4) and is connected to the earth pressure gauge (7). The wire (7-1) of the earth pressure gauge (7) is led out to the ground (14) and connected to a pressure data collector (11); the cylinder structure and the rotating multi-stage oil cylinder (1) perform telescopic movements in the same direction.

2. The hydraulic jacking penetration type in-hole soil pressure measuring device according to claim 1, wherein The orifice positioning structure includes a positioning ring (9-1), a fixing frame (9-2) and a swinging pin (9-3). The fixing frame (9-2) is installed inside the positioning ring (9-1). The operating rod (8-1) penetrates through the center of the fixing frame (9-2) and is connected to the swinging pin (9-3). The swinging pin (9-3) is movably installed on the fixing frame (9-2).

3. The hydraulic jacking penetration type in-hole soil pressure measuring device according to claim 2, wherein, An unthrough groove is provided at the upper part of the center of the fixing frame (9-2), and the swinging pin (9-3) is inserted into the unthrough groove.

4. The hydraulic jacking penetration type in-hole soil pressure measuring device according to claim 3, wherein, The cross-section of the unthrough groove is arc-shaped, and the bottom of the swinging pin (9-3) is arc-shaped to match the arc-shaped unthrough groove; a through groove is provided at the lower part of the center of the fixing frame (9-2). The length axis of the through groove is perpendicular to the length axis of the unthrough groove. The operating rod (8-1) passes through the through groove and is connected to the swinging pin (9-3).

5. The hydraulic jacking and penetration type layered earth pressure measuring device in a borehole according to claim 1, wherein, The fixed housing includes an upper fixed platform (2) and a lower fixed platform (3). The upper fixed platform (2) and the lower fixed platform (3) are respectively detachably connected to the top and bottom of the housing of the rotating multi-stage oil cylinder (1). The cylinder structure includes parallel first cylinders (2-2) and second cylinders (3-1). The first cylinders (2-2) are installed in the upper fixed platform (2), and the second cylinders (3-1) are installed in the lower fixed platform (3). The first cylinders (2-2) and the second cylinders (3-1) are connected to an air pressure regulating console (10) through a gas pipeline; the rotating multi-stage oil cylinder (1) is led out to the ground (14) through a liquid pipeline.

6. The hydraulic jacking penetration type stratified earth pressure measuring device in the borehole according to claim 5, wherein A wire-type displacement gauge (3-6) is provided in the lower fixed platform (3), and the cable of the wire-type displacement gauge (3-6) is led out to the ground (14).

7. The hydraulic jacking penetration type in-hole earth pressure measuring device according to claim 6, characterized in that, The open arc plate (4) is circular-arc-shaped. A through mating groove (4-4) is provided on the open arc plate (4). The mating groove (4-4) includes a communicating vertical groove and a horizontal groove. The mating groove (4-4) mates with a pushing head (5).

8. The hydraulic jacking penetration type stratified earth pressure measuring device in the borehole according to claim 7, characterized in that, A push head (5) is arranged between the built-in piston rod of the rotary multi-section oil cylinder (1) and the earth pressure gauge (7); the push head (5) includes a connected bottom plate (5-1) and an expansion head (5-2), the rear end of the bottom plate (5-1) is fixedly connected to the piston of the rotary multi-section oil cylinder (1), a protruding rod (5-6) is arranged at the bottom end of the bottom plate (5-1), and the protruding rod (5-6) is inserted into the pulling head (3-8) of the wire-pulling displacement gauge (3-6); the expansion head (5-2) is located at the front end of the bottom plate (5-1), and the front end of the expansion head (5-2) is connected to the earth pressure gauge loader (6) through a plurality of inserting rods (5-5), and the earth pressure gauge (7) is installed on the earth pressure gauge loader (6).

9. The hydraulic jacking penetration type in - borehole earth pressure measuring device according to claim 8, wherein, The front end of the earth pressure gauge loader (6) is conical and the rear end is arc-shaped, and the front end of the expansion head (5-2) is arc-shaped and matches the rear end of the earth pressure gauge loader (6).

10. A method for measuring layered earth pressure by hydraulic jacking penetration in a borehole, characterized in that The hydraulic jacking penetration type layered earth pressure measuring device in the borehole as described in any one of claims 1 to 9 is adopted, and the specific steps are as follows: S1, drilling the borehole (15); S2, assembling the penetration structure on the ground (14); S3, installing the orifice positioning structure, the penetration structure and the fixing structure in the borehole (15); S4, backfilling the borehole (15); S5, data acquisition and processing.

Images