CN212779696U - Quick testing arrangement of surrounding rock ground stress in tunnel - Google Patents
Quick testing arrangement of surrounding rock ground stress in tunnel Download PDFInfo
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- CN212779696U CN212779696U CN202021719989.9U CN202021719989U CN212779696U CN 212779696 U CN212779696 U CN 212779696U CN 202021719989 U CN202021719989 U CN 202021719989U CN 212779696 U CN212779696 U CN 212779696U
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Abstract
The utility model discloses a quick testing arrangement of surrounding rock ground stress in tunnel, including ground stress tester, expander and die ware, still include the action bars simultaneously, expander and die ware are fixed in the front end of action bars, still are provided with many high-pressure oil pipes that link to each other with expander and die ware respectively simultaneously in the action bars, high-pressure oil pipe connects in parallel in same high-pressure oil pump through hydraulic pressure change-over switch; meanwhile, the surface of the stamping device is also wrapped with a stamping film layer, and a pressure display module is arranged between the high-pressure oil pump and the ground stress tester; when the utility model is used, the expander and the die stamping device are simultaneously fed into the drilled test hole through the operating rod, the expander realizes high-pressure fracturing on the rock mass, and the die stamping device realizes repeated etching on cracks, thereby realizing whole detection sampling through one device; the ground stress detection device is high in detection efficiency, and meanwhile, the detection cost of the ground stress is reduced.
Description
Technical Field
The utility model relates to a ground stress monitoring technology field, concretely relates to quick testing arrangement of country rock ground stress in tunnel.
Background
The problem of high ground stress always troubles the engineering world, and particularly in the process of tunnel excavation, if tunnel surrounding rocks are hard rocks and are influenced by high ground stress, the risk of rock burst exists; if the tunnel surrounding rock is soft rock, the risk of large deformation of the soft rock is often generated. The existence of the ground stress always brings great risks to tunnel excavation, so the magnitude of the ground stress value is often the main basis for design and constructors to take control measures.
The measurement method of the ground stress can be divided into eight types, namely a stress recovery method, a stress relief method, a strain recovery method, a strain relief method, a hydraulic fracturing method, an acoustic emission method, an X-ray method and a gravity method, according to different measurement principles. Among them, the stress relieving method and the hydraulic fracturing method are 2 ground stress test methods recommended by the international rock mechanics society of 2003.
The stress relieving method is also called a core sleeving method, and is a stress measuring method which is widely applied at present, and the stress relieving method mainly comprises the steps of drilling a measuring hole in rock, installing a measuring sensor in the measuring hole, observing reading, and then concentrically sleeving a drill outside the measuring hole to drill a rock core so as to separate the rock core from surrounding rock; the stress on the core is relieved and elastic recovery occurs. The magnitude and direction of the stress value can be calculated according to the difference value measured by the instrument before and after stress relief; the method has the advantages that the measurement result is accurate, and the three-dimensional stress distribution condition can be obtained even by adopting one drilling hole; the method has the disadvantages that the drilling requirement on the rock core is very high, the measurement success rate is low, and the measurement result is greatly influenced by the quality of the drilled rock core; meanwhile, due to the influence of the drilling technology, the ground stress detection of the deep rock body is greatly limited.
The main principle of the hydraulic fracturing method is that two ends of a rock stratum drill hole are sealed through a sealer, then liquid is injected, the pressure is applied until the hole wall is broken, the change of the pressure along with the time is recorded, and then the breaking direction is observed by an impression device or an underground television; according to the recorded fracture pressure, pump-off pressure and fracture direction, the magnitude and direction of the original main stress can be obtained; the method has the advantages that the requirement on the environment is loose, the absolute stress state at a deeper position can be measured, the elastic modulus of the rock does not need to be known and measured, a core does not need to be sleeved, and the success rate is high; however, the hydraulic fracturing method is mainly used for measuring deep wells on the ground, the used equipment is huge, the hole diameter of the drilled hole is large, the drilling work amount is large, the measuring instrument is expensive, the testing cost is extremely high, the hydraulic fracturing method is suitable for large-scale ground projects, the hydraulic fracturing method cannot be used for quickly measuring the ground stress, and when surrounding rocks are broken, water leakage often occurs, so that the water pressure cannot be increased.
SUMMERY OF THE UTILITY MODEL
Aiming at the defects of high detection cost and difficult operation in the prior art, the utility model discloses a device for rapidly testing the ground stress of surrounding rocks in a tunnel, which is applied to the field of ground stress detection through the ingenious improvement of a hydraulic fracturing method, simplifies the detection operation steps and reduces the detection cost; simultaneously the utility model discloses it is convenient to switch, has reduced the operation degree of difficulty of equipment.
A quick testing device for the ground stress of surrounding rocks in a tunnel comprises a ground stress tester, an expander and an impression device, and further comprises an operating rod, wherein the expander and the impression device are fixedly arranged at the same end of the operating rod; a plurality of high-pressure oil pipes which are respectively communicated with the expander and the die stamping device are arranged in the operating rod, and the other ends of the high-pressure oil pipes are connected with a high-pressure oil pump through a hydraulic change-over switch; the surface of the impression device is wrapped with a printing film layer for engraving rock stratum cracks; and the high-pressure oil pump is connected with a ground stress tester through a pressure display module.
Preferably, the expander and the die are both annular sleeves made of expanded rubber, the annular sleeves are provided with contraction cavities used for containing high-pressure oil, and the contraction cavities are communicated with the high-pressure oil pipes.
Preferably, the operating rod is made of a stainless steel pipe; the printing film layer is made of semi-vulcanized rubber, and the thickness of the printing film layer is 1-3 mm.
Preferably, the other end of the operating rod is connected with an extension sleeve in a threaded mode.
Preferably, the ground stress tester is further provided with a USB interface for connecting the control terminal.
Preferably, the front end of the operating rod is fixedly provided with a conical guide head.
Preferably, the impression device is located at the front end of the expander, and the expander and the impression device are arranged at a distance of 5-10 cm.
Compared with the prior art, the utility model discloses following beneficial effect has:
1. the utility model comprises a ground stress tester, an expander, a die device and an operating rod, wherein the expander and the die device are fixed at the front end of the operating rod, and a plurality of high-pressure oil pipes which are respectively connected with the expander and the die device are arranged in the operating rod and are connected in parallel with the same high-pressure oil pump through a hydraulic change-over switch; meanwhile, the surface of the impression device is also wrapped with an impression film layer (vulcanized rubber), and a pressure display module is also arranged between the high-pressure oil pump and the ground stress tester;
when the utility model is used, the expander and the die device are simultaneously fed into the drilled test hole through the operating rod, then high-pressure hydraulic oil is injected into the expander through the high-pressure oil pump, the expander pushes the inner wall of the hole in the process of expanding all around, and when the pressure of the hydraulic oil is enough, the surrounding rock of the hole wall is cracked at the position of minimum shear stress; releasing the pressure of the expander, adjusting the impression device to the cracking section of the hole wall, and pressurizing the impression device again to ensure that the rock fracturing section is opened again and ensure that semi-vulcanized rubber of the printing film layer is extruded into the gap, thereby realizing the re-engraving operation of crack cracks; the tester combines the reference line of demarcation in advance can be clear and definite learn the trend of the fracture surface that the hole surveyed (the direction of the biggest horizontal main compressive stress promptly), and ground stress tester will be according to time value and the automatic pressure-time curve that generates of received pressure value to transmit this curve to corresponding control computer, the staff can draw ground stress value according to the pressure-time curve combines the analytical method that water caused the fracturing method fast, the utility model discloses a quick acquisition of ground stress value and distribution has improved detection efficiency.
Compared with the prior art, the utility model integrates the expander and the impression device on the same operating rod, and the expander and the impression device do not need to be frequently taken out and put into the hole; meanwhile, the switching among different devices can be completed through the hydraulic change-over switch, the work of expansion cracking and crack re-engraving can be completed in one operation process, the operation is simple and convenient, the detection efficiency is guaranteed, and the detection cost is greatly reduced.
Secondly, the structure of the utility model which extends deep into the hole is only provided with the operating rod, the expander and the die stamping device, therefore, compared with the prior art, the utility model greatly simplifies the detection equipment, the hole drilled in the detection chamber can be smaller, and the detection cost is greatly reduced; simultaneously the utility model discloses a hydraulic pressure replaces water pressure, can reply and reduce supporting pressurized equipment's volume, reduces the hardware cost of equipment, improve equipment's reliability simultaneously.
2. The expander and the die are both annular and made of expanded rubber, and the expander and the die are provided with the contraction cavities communicated with the high-pressure oil pipe, so that the structural design can reduce the size of the expander and the die while ensuring the contraction characteristics of the expander and the die on one hand, further reduce the size of a test hole and reduce the test cost; meanwhile, each component is simple to assemble and easy and convenient to operate, and the testing efficiency is improved.
3. The operating rod of the utility model is made of stainless steel pipe, which improves the structural strength of the operating rod, facilitates taking and placing the expander and the die device, and meanwhile, the operating rod can not be rusted when working in moist environments such as tunnels, and the service life of the operating rod is prolonged; the printing film layer is made of semi-vulcanized rubber, and the thickness of the printing film layer is 1-3mm, so that the source of the printing film layer is wide, and the cost can be reduced; on the other hand, the semi-vulcanized rubber has good engraving effect, and can preserve the engraved lines for 2-3 hours, thereby effectively ensuring the detection timeliness and improving the detection precision; meanwhile, the semi-vulcanized rubber can be recovered automatically, and the raw materials are recycled.
The utility model discloses a 1-3mm thick semi-vulcanized rubber reduces check out test set's volume when it can guarantee to carve seal crackle quantity as seal rete to reduce the internal diameter of test hole, reduce the detection cost.
4. Be provided with the extension sleeve on the action bars, make things convenient for the staff to connect reserve action bars according to operating condition to realize the extension of action bars, satisfy the needs that the deep hole detected.
5. The utility model is also provided with a USB interface connected with the control terminal, and can be conveniently connected with the control terminals such as notebook computers and PC machines through high interfaces, thereby realizing the processes of on-site test, on-site analysis and on-site detection result issuing, and greatly accelerating the detection efficiency; meanwhile, the detection timeliness is also ensured.
6. The utility model discloses be provided with at the front end of action bars fixedly and be conical seeker, will test debris direction both sides in the hole through the seeker, make things convenient for the quick installation of action bars, improve detection efficiency.
7. The die device of the utility model is positioned at the front end of the expander and arranged at an interval of 5-10cm, and the switching between different devices can be realized only by pulling the operating rod outwards in the process of converting the expander into the die device, thereby greatly simplifying the operation procedure of the device and improving the detection efficiency; meanwhile, the distance between the two is 5-10cm, the problems of drilling depth extension and complex operation caused by overlarge distance can be avoided, the problem of equipment mutual interference caused by too short distance can be avoided, the detection precision of the equipment is improved, and the detection cost is reduced.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is an enlarged schematic view of part A of the present invention;
FIG. 3 is a schematic view of the expander of the present invention;
reference numerals: 1. the device comprises a ground stress tester 2, an expander 3, an impression device 4, an operating rod 5, a high-pressure oil pipe 6, a hydraulic change-over switch 7, a high-pressure oil pump 8, a printing film layer 9, a pressure display module 10, a contraction cavity 11, an extension sleeve 12, a USB interface 13 and a seeker.
Detailed Description
The present invention will be further explained by the following embodiments:
embodiment mode 1
The embodiment is taken as the basic embodiment of the utility model, and discloses a device for rapidly testing the ground stress of surrounding rocks in a tunnel, the concrete structure is shown in fig. 1 and fig. 3, and the device comprises a ground stress tester 1, an expander 2, an impression device 3 and an operating rod 4, wherein the operating rod 4 is made of a stainless steel pipe, one end of the operating rod is in threaded connection with an extension sleeve 11, the expander 2 and the impression device 3 are both fixedly arranged at the other end of the operating rod 4, the impression device 3 is positioned at the front end of the expander 2 during installation, the installation distance between the expander and the impression device is 5-10cm according to requirements, and a conical guide head 13 is also arranged at the top end of the operating rod 4;
the expander 2 and the impression device 3 are both made of expanded rubber and are both of annular structures, so that the expander 2 and the impression device 3 are sleeved on the operating rod 4, meanwhile, the expander 2 and the impression device 3 are both provided with a contraction cavity 10, the contraction cavity 10 is provided with two connectors communicated with the outside, 4 high-pressure oil pipes 5 are arranged in the operating rod 4, two of the high-pressure oil pipes are oil inlet pipes and two of the high-pressure oil pipes are pressure relief pipes, the connectors of the expander 2 and the impression device 3 are respectively connected with one oil inlet pipe and one pressure relief pipe, the other ends of the two pressure relief pipes are connected with oil return ports of a high-pressure oil pump 7, the other ends of the two oil inlet pipes are connected with different outlets of a hydraulic change-over switch 6, and the inlet end of the hydraulic change-over;
the high-pressure oil pump 7 is also connected with a pressure display module 9 for displaying the pressure of the hydraulic oil, and the pressure display module 9 can be a needle type indicator or a digital detection module; meanwhile, the pressure display module 9 is also connected with the signal input end of the ground stress tester 1 through a connecting wire, so that the corresponding pressure value is transmitted to the ground stress tester 2 in real time; meanwhile, the ground stress tester 2 is also provided with a USB interface 12, so that the ground stress tester can be conveniently connected with control terminals such as a notebook computer and a PC end in real time;
the surface of the die plate 3 is further wrapped with a printing film layer 8, the thickness of the printing film layer 8 is 1-3mm according to actual process requirements, and meanwhile the printing film layer 8 is made of semi-vulcanized rubber.
The use method of the device comprises the following steps: s1, inserting the expander and the impression device into the drilled detection hole through the operating rod;
s2, opening the high-pressure oil pump, simultaneously communicating the expander through the hydraulic reversing switch, and closing the impression device; observing a change in a value of the pressure display module during pressurization of the expander;
s3, when the pressure value displayed by the pressure display module is suddenly reduced, confirming that the surrounding rock of the hole wall is cracked in the direction of the minimum shear stress, and taking the maximum value of the oil pressure as an initial cracking pressure value Pb;
s4, stopping pressurization by closing the high-pressure oil pump, finishing the pressure relief operation of the expander, gradually closing the crack, and recording the crack closing pressure Ps (namely the minimum horizontal principal stress);
s5, pulling out the operating rod outwards, withdrawing the expander from the fracturing section, moving the impression device to the fracturing section, pressurizing the impression device through a hydraulic change-over switch to re-open the fracturing section, extruding the semi-vulcanized rubber into the crack, and finishing re-engraving the crack; keeping the state for 30-50min, and recording the re-tensioning pressure Pr of the crack;
s5, repeating the steps S2-S5 for 3-5 times to obtain multiple groups of closing pressure Ps and re-opening pressure Pr, and taking the corresponding average value as the final calculation value;
s6, the impression device is decompressed, and the operating rod is pulled out after decompression is finished, so that the whole set of equipment is taken out; then covering a transparent plastic film on the surface of the printing film layer, drawing corresponding imprints and baselines on the surface of the film layer, and determining the trend of the measured fracture surface (namely the direction of the maximum horizontal main compressive stress) by combining the ground stress value detected by a ground stress tester;
the following is the process of calculating the stress specifically for Pb, Ps and Pr, which is a common method at home and abroad.
(hydraulic pressure greater than the stress that the rock can withstand on the hole wall, will produce the fracture at the position of minimum tangential stress, and will expand in the direction perpendicular to the minimum principal stress, at which point the pressure Pb at which the hole wall fractures becomes the initial fracture pressure value (also called critical fracture pressure), Pb being equal to the stress concentration at the hole wall fracture plus the tensile strength T of the rock, i.e.:
Pb＝3Sh-SH+T-P0 (2-1)
in the formula: shIs the minimum horizontal principal stress, S, in the in situ stress fieldHIs the maximum horizontal principal stress in the in situ stress field, T is the tensile strength of the rock, P0For pore pressure existing in rock, since the depth of a hole is usually about 30 m in a tunnel, the pore pressure can be disregarded, so that P is assumed0＝0。
After the hole wall is broken, if pressurization is continued, the crack will expand to the longitudinal depth. At the moment, pressurization is stopped, the fracturing loop is kept closed, the fracture stops extending, the fracture tends to close under the action of the ground stress field, and the equilibrium pressure of the fracture in a critical closing state is called fracture closing pressure Ps, which is equal to the minimum horizontal principal stress of a vertical fracture surface:
Ps＝Sh (2-2)
at this time, the pressure is applied again to re-open the fracture to obtain a pressure Pr for re-opening the fracture, and since the rock is already fractured and the tensile strength T of the rock is 0, the formula 2-1 can be rewritten into
Pr＝3Sh-SH-P0 (2-3)
Subtracting 2-3 from formula 2-1 to obtain T ═ Pb-Pr (2-4)
S can be obtained by the formulae 2-2 and 2-3H＝3Ps-Pb-P0 (2-5)
In summary, the maximum and minimum horizontal principal stresses are determined from the detected Pb, Ps and Pr values.
Compared with the prior art, the utility model integrates the expander and the die stamping device on the same operating rod, and the expander and the die stamping device are pressurized successively by the hydraulic device, so that the expander and the die stamping device do not need to be taken out and put into the hole frequently; meanwhile, the switching among different devices can be completed through the hydraulic change-over switch, all tests can be completed in one operation process, the operation is simple and convenient, and the test efficiency is effectively ensured; compare with water pressure pressurization mode simultaneously, the utility model discloses can also effectively reduce the volume of compression equipment, be favorable to reducing the hardware cost of equipment, improve equipment's reliability.
Claims (7)
1. The utility model provides a quick testing arrangement of country rock crustal stress in tunnel, includes ground stress tester (1), expander (2) and impression ware (3), its characterized in that: the testing device also comprises an operating rod (4), and the expander (2) and the die stamping device (3) are fixedly arranged at the same end of the operating rod (4); a plurality of high-pressure oil pipes (5) which are respectively communicated with the expander (2) and the die stamping device (3) are arranged in the operating rod (4), and the other ends of the high-pressure oil pipes (5) are connected with a high-pressure oil pump (7) through a hydraulic change-over switch (6); the surface of the die stamping device (3) is wrapped with a film stamping layer (8) for stamping rock stratum cracks; the high-pressure oil pump (7) is connected with the ground stress tester (1) through a pressure display module (9).
2. The device for rapidly testing the geostress of the surrounding rock in the tunnel according to claim 1, is characterized in that: the expander (2) and the die device (3) are both annular sleeves made of expanded rubber, the annular sleeves are provided with contraction cavities (10) used for containing high-pressure oil, and the contraction cavities (10) are communicated with the high-pressure oil pipes (5).
3. The device for rapidly testing the crustal stress of the surrounding rock in the tunnel according to claim 1, wherein the operating rod (4) is made of stainless steel pipes; the film printing layer (8) is made of semi-vulcanized rubber, and the thickness of the film printing layer is 1-3 mm.
4. The device for rapidly testing the geostress of the surrounding rock in the tunnel according to claim 1, is characterized in that: the other end of the operating rod (4) is connected with an extension sleeve (11) in a threaded manner.
5. The device for rapidly testing the geostress of the surrounding rock in the tunnel according to claim 1, is characterized in that: the ground stress tester (1) is also provided with a USB interface (12) for connecting a control terminal.
6. The device for rapidly testing the geostress of the surrounding rock in the tunnel according to claim 1, is characterized in that: the front end of the operating rod (4) is fixedly provided with a conical guide head (13).
7. The device for rapidly testing the geostress of the surrounding rock in the tunnel according to claim 1, is characterized in that: the expander (2) and the impression device (3) are arranged at a distance of 5-10 cm.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202021719989.9U CN212779696U (en) | 2020-08-18 | 2020-08-18 | Quick testing arrangement of surrounding rock ground stress in tunnel |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113237811A (en) * | 2021-04-27 | 2021-08-10 | 深圳大学 | Combined test method for in-situ coal seam permeability and mining stress |
| CN115077757A (en) * | 2022-05-12 | 2022-09-20 | 三峡大学 | Device and method for rapidly measuring ground stress on site |
-
2020
- 2020-08-18 CN CN202021719989.9U patent/CN212779696U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113237811A (en) * | 2021-04-27 | 2021-08-10 | 深圳大学 | Combined test method for in-situ coal seam permeability and mining stress |
| CN115077757A (en) * | 2022-05-12 | 2022-09-20 | 三峡大学 | Device and method for rapidly measuring ground stress on site |
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