Rock and soil mass mechanical parameter measuring system and method

Abstract

The invention discloses a rock-soil body mechanical parameter measurement system and method, and the system comprises an elastic sleeve which is used for being implanted into a rock-soil body and is internally provided with a deformation cavity; the sensing optical cable is distributed along the axial direction of the elastic sleeve and is in contact with the elastic sleeve; the optical fiber demodulator is electrically connected with the sensing optical cable and can demodulate an optical signal of the sensing optical cable to generate optical cable measurement data; the pressure source is used for providing pressure fluid; the pressure source can be communicated with the deformation cavity through the pressure control structure; the pressure detection mechanism is used for collecting pressure data of the deformation cavity; and the data analysis mechanism is used for analyzing, processing and generating mechanical parameters of the rock-soil body according to the pressure data and the optical cable measurement data. The sensing optical cable is distributed in the axial direction of the elastic sleeve and makes contact with the elastic sleeve, distributed measurement of the mechanical parameters of the rock-soil body can be achieved by analyzing the relation between the signal change of the sensing optical cable and the change of the rock-soil body, and the measurement result is more accurate.

Description

Technical Field

[0001] This invention relates to the field of geotechnical mechanics, and in particular, to a system and method for measuring the mechanical parameters of geotechnical bodies. Background Technology

[0002] In-situ testing technology for soil and rock masses refers to geotechnical and geomechanical tests conducted on-site to obtain various mechanical parameters of soil and rock masses. It is an important means of evaluating the mechanical properties of soil and rock masses and the quality of geotechnical engineering projects. In-situ testing technologies for soil and rock masses include standard penetration tests (SPT), dynamic penetration tests, static cone penetration tests (PCT), ultrasonic tests, resistivity and stress wave measurements, foundation bearing capacity tests, and pressuremeter tests. Currently, in-situ testing technologies for soil and rock masses still face common problems such as insufficient accuracy, incomplete testing indicators, high costs, and low testing efficiency.

[0003] Among them, the pressuremeter test is a commonly used method for testing the strength parameters of soil and rock masses. Its basic principle is to apply pressure to the side of the specimen and calculate parameters such as compression modulus and shear strength by measuring the deformation and instability force of the specimen. Since the invention of the Mena pressuremeter, the application of pressuremeter testing in in-situ testing of soil and rock masses has been very widespread. Various modifications have been made to the Mena pressuremeter as needed, but the modified pressuremeter testing devices and methods still have many problems. In addition to the aforementioned common problems such as insufficient accuracy, incomplete test indicators, high cost, and low testing efficiency, there are also issues such as poor mobility due to the large number of instrument components and strict requirements for the operating environment. Furthermore, existing single-cavity and multi-cavity pressuremeters are still inadequate for cross-layer measurements. Moreover, since the measurement only measures the overall volume change of the pressuremeter, it cannot reveal the differences in soil and rock strength at different locations around the borehole wall at the same layer.

[0004] One of the most prominent problems is that current testing technologies struggle to achieve distributed measurements, i.e., spatiotemporal continuity measurements. Typically, testing tools need to be advanced to a target layer using various methods before measurement, and then retrieved for the next target layer. This point-based method also struggles to provide permanent measurements, only allowing for periodic or ad-hoc data collection, making it difficult to reveal the historical dynamic evolution of geological bodies. However, many geological problems and engineering scenarios demand highly continuous spatiotemporal measurements of soil and rock mechanical parameters, such as changes in mechanical parameters caused by fluid replacement during carbon dioxide sequestration or oil displacement, and changes in foundation mechanical parameters during the frost heave and thaw settlement of seasonally frozen soil. Summary of the Invention

[0005] The purpose of this invention is to provide a system and method for measuring the mechanical parameters of soil and rock, so as to solve the technical problem that the existing technology cannot achieve distributed measurement of the mechanical parameters of soil and rock.

[0006] The above-mentioned objectives of the present invention can be achieved by the following technical solutions: This invention provides a system for measuring the mechanical parameters of soil and rock, comprising: an elastic sleeve for implanting into soil and rock, wherein the elastic sleeve has a deformation cavity; a sensing optical cable distributed along the axial direction of the elastic sleeve and in contact with the elastic sleeve; an optical fiber demodulator electrically connected to the sensing optical cable and capable of demodulating and processing the optical signal of the sensing optical cable to generate optical cable measurement data; a pressure source for providing pressure fluid; a pressure control structure, wherein the pressure source can be connected to the deformation cavity through the pressure control structure; a pressure detection mechanism for collecting pressure data from the deformation cavity; and a data analysis mechanism for analyzing and processing the pressure data and the optical cable measurement data to generate the mechanical parameters of the soil and rock.

[0007] In an embodiment of the present invention, the sensing optical cable is spirally wound around the inner wall surface or inside the wall of the elastic sleeve along the axial direction of the elastic sleeve.

[0008] In an embodiment of the present invention, there is an angle between the radial direction of the sensing optical cable and the elastic sleeve, and the angle is less than 5 degrees.

[0009] In embodiments of the present invention, the optical cable measurement data includes temperature measurement results and strain measurement results of the sensing optical cable; the sensing optical cable is a composite sensing optical cable; the composite sensing optical cable has a temperature sensing fiber and a strain sensing fiber; the fiber demodulator is a composite fiber demodulator, which includes at least one temperature fiber demodulation module and at least one strain fiber demodulation module. The temperature fiber demodulation module is electrically connected to the temperature sensing fiber and can demodulate the optical signal of the temperature sensing fiber into the temperature measurement result. The strain fiber demodulation module is electrically connected to the strain sensing fiber and can demodulate the optical signal of the strain sensing fiber into the strain measurement result.

[0010] In an embodiment of the present invention, the elastic sleeve is further provided with a flow structure and a plurality of sealing structures. The flow structure passes through the elastic sleeve along the axial direction of the elastic sleeve. There is an annular space between the flow structure and the elastic sleeve. The annular space constitutes the deformation cavity. The plurality of sealing structures are arranged at intervals along the axial direction of the deformation cavity and divide the elastic sleeve into a plurality of deformation segments. The deformation cavity is divided into a plurality of deformation sub-cavities. Each deformation sub-cavity is connected to the pressure control structure through the flow structure.

[0011] In an embodiment of the present invention, the pressure detection mechanism includes an underground pressure detection structure, which further includes a signal transmission optical cable and multiple fiber optic pressure gauges. The multiple fiber optic pressure gauges are connected in series on the signal transmission optical cable and are correspondingly distributed within the multiple deformable sections. The pressure data of the deformable cavity includes the pressure data of each of the deformable sub-cavities. The fiber optic demodulator also has at least one pressure fiber optic demodulation module, which is electrically connected to the signal transmission optical cable and can demodulate the optical signals of each fiber optic pressure gauge into pressure data of each of the deformable sub-cavities.

[0012] In an embodiment of the present invention, the flow structure includes a flow pipeline with multiple through holes arranged thereon, and the flow pipeline connects to each of the deformable sub-cavities through the multiple through holes.

[0013] In an embodiment of the present invention, the pressure control structure includes a pressure control pipeline, a pressure reducing valve, a regulating valve, and a pressure relief valve. The pressure control pipeline connects the pressure source and the deformation cavity, and the pressure reducing valve, the regulating valve, and the pressure relief valve are installed on the pressure control pipeline.

[0014] In an embodiment of the present invention, the pressure detection mechanism includes a ground pressure detection structure, which includes an output pressure detection element, a low-pressure detection element, a medium-pressure detection element, a high-pressure detection element, and an input pressure detection element. The input pressure detection element is located at the input end of the pressure control pipeline, and the output pressure detection element is located at the output section of the pressure control pipeline. The low-pressure detection element, the medium-pressure detection element, and the high-pressure detection element are connected in parallel on the pressure control pipeline.

[0015] This invention also provides a method for measuring the mechanical parameters of soil and rock, comprising the following steps: implantation: implanting an elastic sleeve with a sensing optical cable installed into the soil and rock; wherein the sensing optical cable is distributed along the axial direction of the elastic sleeve and contacts the elastic sleeve; loading: injecting pressurized fluid into the deformation cavity of the elastic sleeve to expand the elastic sleeve; unloading: discharging the pressurized fluid from the deformation cavity to retract the elastic sleeve; data acquisition: during the loading and unloading steps, a pressure detection mechanism acquires pressure data of the deformation cavity, and an optical fiber demodulator demodulates the optical signal of the sensing optical cable into optical cable measurement data; data analysis: analyzing and processing the pressure data and the optical fiber measurement data to generate the mechanical parameters of the soil and rock.

[0016] In an embodiment of the present invention, the sensing optical cable has a temperature sensing fiber and a strain sensing fiber; the optical cable measurement data includes the temperature measurement result and the strain measurement result of the sensing optical cable; the mechanical parameters include the shear modulus of the rock and soil; the data analysis step specifically includes the following steps: analyzing and processing the temperature measurement result and the strain measurement result to generate the circumferential strain of the elastic sleeve; plotting a pressure-circumferential strain curve based on the circumferential strain and the pressure data; selecting the linear segment of the pressure-circumferential strain curve, and then calculating the shear modulus of the rock and soil; wherein, the shear modulus of the rock and soil is the slope of the linear segment.

[0017] In embodiments of the present invention, the mechanical parameters further include the deformation modulus of the rock and soil mass; the data analysis step further includes: generating the deformation modulus of the rock and soil mass based on the shear modulus analysis.

[0018] The features and advantages of this invention are: The rock and soil mechanical parameter measurement system and method of the present invention distributes sensing optical cables along the axial direction of an elastic sleeve and contacts the elastic sleeve. After being implanted into the rock and soil along with the elastic sleeve, the changes in different parts of the elastic sleeve caused by the pressure fluid in its internal deformation cavity and the rock and soil of different layers outside can be transmitted to the sensing optical cables. By analyzing the relationship between the signal changes of the sensing optical cables and the changes in the rock and soil, the distributed measurement of the mechanical parameters of the rock and soil can be realized, and the measurement results are more accurate. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a diagram showing the usage status of the soil and rock mechanical parameter measurement system in this invention.

[0021] Figure 2 This is another usage state diagram of the rock and soil mechanical parameter measurement system in this invention.

[0022] Figure 3 This is a schematic diagram of the sensing optical cable in this invention.

[0023] Figure 4 This is a schematic diagram of the elastic sleeve in this invention.

[0024] Figure 5 This is a partial perspective view of the elastic sleeve in this invention.

[0025] Figure 6 This is a partial cross-sectional view of an elastic sleeve according to an embodiment of the present invention.

[0026] Figure 7 This is a partial cross-sectional view of an elastic sleeve according to another embodiment of the present invention.

[0027] Figure 8 This is a flowchart illustrating the calculation of mechanical parameters in this invention.

[0028] In the picture: 1. Elastic sleeve; 11. Deformation cavity; 111. Deformation sub-cavity; 12. Flow structure; 121. Through hole; 13. Sealing structure; 14. Deformation section; 15. Elastic tube body; 16. Bottom seal; 17. Cap; 18. Top clamp; 2. Pressure control structure; 21. Pressure control pipeline; 22. Pressure reducing valve; 23. Regulating valve; 24. Pressure relief valve; 25. Control box; 3. Pressure source; 31. High-pressure gas cylinder; 32. Gas valve; 4. Pressure testing mechanism; 41. Ground pressure testing structure; 411. Output pressure testing element; 412. Low-pressure testing element; 413. Medium-pressure testing element; 414. High-pressure testing element; 415. Input pressure testing element; 42. Underground pressure detection structure; 421. Signal transmission optical cable; 422. Fiber optic pressure gauge; 5. Sensing optical cable; 51. Strain sensing optical fiber; 52. Temperature sensing optical fiber; 53. Coating layer; 54. Sheath; 6. Fiber optic demodulator; 7. Jumper wire; 100. Rock and soil mass; 101. In-situ strata; 102. Geological model. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Implementation Method 1

[0031] like Figure 1 and Figure 2As shown, the present invention provides a soil and rock mechanical parameter measurement system, comprising: an elastic sleeve 1 for implanting into a soil and rock mass 100, and the elastic sleeve 1 having a deformation cavity 11; a sensing optical cable 5 distributed along the axial direction of the elastic sleeve 1 and in contact with the elastic sleeve 1; an optical fiber demodulator 6 electrically connected to the sensing optical cable 5 and capable of demodulating and processing the optical signal of the sensing optical cable 5 to generate optical cable measurement data; a pressure source 3 for providing pressure fluid; a pressure control structure 2, through which the pressure source 3 can be connected to the deformation cavity 11; a pressure detection mechanism 4 for collecting pressure data from the deformation cavity 11; and a data analysis mechanism for analyzing and processing the pressure data and the optical cable measurement data to generate the mechanical parameters of the soil and rock mass 100.

[0032] Among them, the sensing optical cable 5 is based on distributed fiber optic sensing technology (DFOS) to realize the measurement. The principle is that the optical fiber in the sensing optical cable 5 is easily affected by the external environment (such as temperature, strain, etc.), which causes changes in the intensity, phase, frequency, polarization state and other light wave quantities during the transmission of light through the optical fiber. Then, by demodulating the optical signal through the fiber demodulator 6, information such as temperature and strain can be determined. The sensing optical cable 5 has the advantages of being passive, corrosion-resistant, anti-interference, easy to reuse, and capable of distributed monitoring, thus enabling continuous, high-precision and large-scale distributed dynamic measurement of the rock and soil mass 100.

[0033] The pressure fluid can be gas, as in the embodiments of the present invention, and the pressure source 3 is a high-pressure gas cylinder 31. The high-pressure gas cylinder 31 is equipped with a gas valve 32 for controlling the output of the internal pressure fluid; of course, the pressure fluid can also be liquid. The pressure control structure 2 can control the input of pressure fluid into the deformation cavity 11 to control the expansion and deformation of the elastic sleeve 1 under the action of the pressure fluid, and can also control the discharge of pressure fluid in the deformation cavity 11 to control the retraction and deformation of the elastic sleeve 1. During the deformation process of the elastic sleeve 1, the sensing optical cable 5 deforms along with the elastic sleeve 1, and the rock and soil 100 is also deformed due to the deformation of the elastic sleeve 1.

[0034] The soil and rock mechanical parameter measurement system of the present invention, by distributing the sensing optical cable 5 along the axial direction of the elastic sleeve 1 and contacting the elastic sleeve 1, and then embedding it together with the elastic sleeve 1 into the soil and rock mass 100, can transmit the changes in different parts of the elastic sleeve 1 caused by the pressure fluid in its internal deformation cavity 11 and the different layers of soil and rock mass 100 outside to the sensing optical cable 5. Thus, by analyzing the relationship between the signal changes of the sensing optical cable 5 and the changes in the soil and rock mass 100, the distributed measurement of the mechanical parameters of the soil and rock mass 100 can be realized, and the measurement results are more accurate.

[0035] Specifically, the soil and rock mass 100 can be either in-situ strata 101 or a geological model 102. In other words, the soil and rock mass mechanical parameter measurement system of this invention can achieve on-site measurement of the mechanical parameters of the in-situ strata 101, and can also achieve laboratory measurement of the mechanical parameters of the geological model 102. The elastic sleeve 1 can be implanted into the soil and rock mass 100 by drilling, pressing, or pre-embedding.

[0036] The number and type of optical fibers in the sensing optical cable 5 are not specifically limited and can be selectively set according to the mechanical parameters of the soil and rock mass 100 to be measured. For example... Figure 3 As shown, in some embodiments of the present invention, the optical cable measurement data includes temperature data and strain data of the sensing optical cable 5; the sensing optical cable 5 is a composite sensing optical cable; the composite sensing optical cable has a temperature sensing fiber 52 and a strain sensing fiber 51; the fiber demodulator 6 is a composite fiber demodulator, which includes at least one temperature fiber demodulation module and at least one strain fiber demodulation module. The temperature fiber demodulation module is electrically connected to the temperature sensing fiber 52 and can demodulate the optical signal of the temperature sensing fiber 52 into temperature data. The strain fiber demodulation module is electrically connected to the strain sensing fiber 51 and can demodulate the optical signal of the strain sensing fiber 51 into strain data. Since the elastic deformation of the elastic sleeve 1 caused by the pressure fluid in its internal deformation cavity 11 and the external rock and soil 100 can be transmitted to the strain sensing fiber 51 and cause the rock and soil 100 to deform, the deformation of the rock and soil 100 can be analyzed based on the strain of the strain sensing fiber 51. However, in order to make the measurement results more accurate, by setting the temperature sensing fiber 52, temperature compensation can be performed based on the temperature data to filter out the influence of temperature effect on the measurement results.

[0037] Specifically, the sensing optical cable 5 is a strain-sensitized sensing optical cable, with a sheath 54 and a coating layer 53 arranged sequentially from the outside to the inside. The temperature sensing fiber 52 and the strain sensing fiber 51 are wrapped in the coating layer 53. The communication end of the sensing optical cable 5 extends out of the elastic sleeve 1 and can be electrically connected to the fiber optic demodulator 6 via a jumper 7. The temperature fiber optic demodulation module can be an existing Raman scattering demodulation module; the strain fiber optic demodulation module can be an existing Brillouin scattering demodulation module, Rayleigh scattering demodulation module, or Bragg grating demodulation module. The working principle of the fiber optic demodulator 6 in demodulating the sensing optical cable 5 into optical cable measurement data is the same as that of existing technology and will not be described in detail here.

[0038] Combination Figure 1 , Figure 2 as well as Figure 8As shown, in some embodiments of the present invention, the mechanical parameters may include the shear modulus of the soil-rock mass 100; the data analysis mechanism analyzes and processes the temperature measurement results and strain measurement results to generate the circumferential strain of the elastic sleeve 1; the pressure-circumferential strain curve is plotted based on the circumferential strain and pressure data analysis and processing; the linear segment of the pressure-circumferential strain curve is selected, and then the shear modulus of the soil-rock mass 100 is calculated; wherein, the shear modulus of the soil-rock mass 100 is the slope of the linear segment.

[0039] Specifically, since the strain measurement results directly measured by the strain sensing fiber 51 of the sensing optical cable 5 are affected by temperature, it is necessary to perform temperature compensation on the strain measurement results based on the temperature measurement results of the temperature sensing fiber 52. This is done first according to the formula... The temperature and strain measurements directly measured by the sensing optical cable 5 are converted into the circumferential strain of the elastic sleeve 1; where Δε is the strain measurement result of the strain sensing optical fiber 51; Δ T The temperature measurement results of the temperature sensing fiber optic cable 52; ε c For circumferential strain; K ε The inductive coefficient of the optical fiber transmission; K t The temperature coefficient of fiber optic sensing; During the test, pressure data, temperature measurement results, and strain measurement results were continuously collected, analyzed, and processed to generate the corresponding circumferential strain. Then, a pressure-circumferential strain curve was plotted based on the pressure data and circumferential strain. The slope of the linear segment of the curve was calculated, which is the shear modulus of the soil / rock mass 100. G This is equivalent to using a formula. G= Δ P / Δε c Calculate the shear modulus G ; where Δ P Δε represents the change (e.g., increment) in pressure exerted by the elastic sleeve 1 on the soil mass 100. c This represents the change (e.g., increment) in the circumferential strain of the elastic sleeve 1. Since part of the pressure of the fluid injected into the elastic sleeve 1 is applied to the soil-rock mass 100 through the deformation of the elastic sleeve 1, causing the soil-rock mass 100 to deform, and part of the pressure is consumed by the elastic sleeve 1 itself, the pressure exerted by the elastic sleeve 1 on the soil-rock mass 100 needs to be corrected based on the measurement of the fluid pressure in the deformation cavity 11 inside the elastic sleeve 1 (i.e., the pressure data of the deformation cavity 11 directly measured by the pressure detection mechanism 4 during the test).

[0040] Specifically, P = P i - P c ,in, PThe pressure exerted by the elastic sleeve 1 on the rock and soil mass 100, P i The fluid pressure inside the internal deformation cavity 11 P c To correct the constraint force of the elastic sleeve 1, the value can be obtained by calibrating the elastic sleeve 1 under unconfined conditions. Specifically, before the geotechnical mechanics parameter measurement system leaves the factory, a series of pressure and decompression tests are conducted on the interior of the elastic sleeve 1, recording the circumferential strain ε of the elastic sleeve 1 during pressure changes. c and the corresponding fluid pressure (i.e. P c Establish "circumferential strain ε" c - Fluid pressure P c The reference table for the correction of "".

[0041] Furthermore, the deformation modulus of the soil-rock mass 100 can be generated based on shear modulus analysis. This deformation modulus includes both tensile and compressive moduli. Specifically, the formula is used... The shear modulus analysis was used to generate the deformation modulus of the soil mass 100; among which, E Modulus of deformation; v Poisson's ratio for rock and soil mass 100 (such as in-situ strata 101 or geological model 102).

[0042] like Figure 4 As shown, in an embodiment of the present invention, the sensing optical cable 5 is spirally wound around the inner wall or interior of the elastic sleeve 1 along its axial direction. Changes in the axial and circumferential directions of the elastic sleeve 1 caused by the internal pressure fluid and the external soil and rock mass 100 can be transmitted to the sensing optical cable 5, causing corresponding changes in the optical signal of the sensing optical cable 5. Thus, based on the changes in the optical signal of the sensing optical cable 5, the mechanical parameters of the soil and rock mass 100 can be measured across the entire cross-section.

[0043] Specifically, the radial direction of the sensing optical cable 5 and the elastic sleeve 1 (i.e., Figure 4 There is an angle between the horizontal direction (from the perspective) and the horizontal direction. included angle The angle is less than 5 degrees. This ensures that when the sensing optical cable 5 deforms with the elastic sleeve 1 during the measurement process, all positions of the sensing optical cable 5 are under tension, thus having a certain degree of deformation. This ensures the accuracy of the measurement and avoids situations where some positions of the sensing optical cable 5 are under compression, resulting in insignificant deformation and making it impossible to accurately measure the strain data at the corresponding positions of the elastic sleeve 1.

[0044] like Figure 1 , Figure 2 as well as Figure 4 , Figure 5As shown, in an embodiment of the present invention, the elastic sleeve 1 is further provided with a flow structure 12 and a plurality of sealing structures 13. The flow structure 12 passes through the elastic sleeve 1 along the axial direction of the elastic sleeve 1. There is an annular space between the flow structure 12 and the elastic sleeve 1. The annular space constitutes a deformation cavity 11. The plurality of sealing structures 13 are arranged at intervals along the axial direction of the deformation cavity 11 and divide the elastic sleeve 1 into a plurality of deformation segments 14. The deformation cavity 11 is divided into a plurality of deformation sub-cavities 111. Each deformation sub-cavity 111 is connected to the pressure control structure 2 through the flow structure 12. Multiple sealing structures 13 divide the elastic sleeve 1 into multiple deformable segments 14 and the deformation cavity 11 into multiple deformable sub-cavities 111. The pressurized fluid flows into the flow structure 12 through the pressure control structure 2, and then flows into each deformable sub-cavity 111 from the flow structure 12. Alternatively, the pressurized fluid in each deformable sub-cavity 111 flows into the pressure control structure 2 from the flow structure 12 and then is discharged. This allows each deformable segment 14 of the elastic sleeve 1 to deform under the action of the pressurized fluid in the corresponding deformable sub-cavity 111, causing the surrounding rock and soil mass 100 to deform accordingly. This avoids uneven stress on the elastic sleeve 1, resulting in only local deformation and causing only local deformation of the rock and soil mass 100, which would prevent the simultaneous measurement of the mechanical parameters of different layers of the rock and soil mass 100.

[0045] Specifically, such as Figure 4 As shown, the elastic sleeve 1 includes an elastic tube body 15, a cap 17, and a bottom cap 16. The cap 17 is sealed at the top opening of the elastic tube body 15, and the bottom cap 16 is sealed at the bottom opening of the elastic tube body 15, thus sealing the inner cavity of the elastic tube body 15. The cap 17 can be installed at the top opening of the elastic tube body 15 via a top clamp 18. The communication end of the sensing optical cable 5 can pass through the top clamp 18 or the cap 17 and be electrically connected to the fiber optic demodulator 6 via a jumper wire 7. Figure 5 and Figure 6 As shown, the flow structure 12 includes a flow pipe with multiple through holes 121 arranged on it, connecting each deformable sub-cavity 111. The flow pipe passes through the elastic tube body 15, with one end fixed to the bottom seal 16 and the other end exiting from the cap 17 and connected to the pressure source 3 through the pressure control structure 2. The bottom seal 16 and the top clamp 18 can be connected to the elastic tube body 15 by welding, riveting, countersunk screws, or bonding; the cap 17 can also be connected to the top clamp 18 by welding, riveting, countersunk screws, or bonding.

[0046] Furthermore, the flow pipeline can be made of rigid pipe material that is not easily deformed. The sealing structure 13 is generally a rigid ring structure and is connected to the outer wall of the flow pipeline and the inner wall of the elastic tube 15. This helps to improve the structural stability of the elastic sleeve 1, facilitates its implantation into the soil 100, and also improves the pressure-bearing capacity of the elastic sleeve 1, enabling it to withstand the lateral pressure of the high-strength soil 100. When measuring the mechanical parameters of the soil 100 with lower strength, the flow structure 12 and the sealing structure 13 can be omitted, and the entire inner cavity of the elastic sleeve 1 can be used as the deformation cavity 11.

[0047] like Figure 1 and Figure 2 As shown, in an embodiment of the present invention, the pressure control structure 2 includes a pressure control pipeline 21, a pressure reducing valve 22, a regulating valve 23, and a pressure relief valve 24. The pressure control pipeline 21 connects the pressure source 3 and the deformation chamber 11. The pressure reducing valve 22, the regulating valve 23, and the pressure relief valve 24 are installed on the pressure control pipeline 21. Specifically, one end of the pressure control pipeline 21 is connected to the pressure source 3, and the other end of the pressure control pipeline 21 is connected to the deformation chamber 11 through a flow pipeline. The pressure control pipeline 21 has an input pipe connected to the pressure source 3, an output pipe connected to the deformation chamber 11, an intermediate pipe connecting the input pipe and the output pipe, and a pressure relief pipe connected to the intermediate pipe. The intermediate pipe and the pressure relief pipe are installed in a control box 25. The pressure reducing valve 22 for reducing the gas source pressure and the regulating valve 23 for adjusting and controlling the pressure are installed on the intermediate pipe along the input direction. The pressure relief valve 24 is installed on the pressure relief pipe and located upstream of the pressure reducing valve 22, and the pressure is released after the test is completed. During the process of increasing the pressure of the deformation cavity 11 by injecting pressurized fluid into the deformation cavity 11, the pressure of the injected pressurized fluid can be controlled by the pressure reducing valve 22 and the regulating valve 23. During the process of decreasing the pressure of the deformation cavity 11 by discharging the pressurized fluid from the deformation cavity 11, the pressure relief valve 24 and the regulating valve 23 can be used to control the pressurized fluid to be discharged at a certain rate.

[0048] Since the pressure of the deformation cavity 11 is similar to the pressure of the pipe directly or indirectly connected to it, in the embodiments of the present invention, the pressure detection mechanism 4 can directly measure the pressure of the deformation cavity 11, or indirectly measure the pressure data of the deformation cavity 11 by measuring the pressure of the pipe directly or indirectly connected to the deformation cavity 11 (such as the output pipe, intermediate pipe or input pipe of the pressure control pipeline 21).

[0049] like Figure 7As shown, in some embodiments of the present invention, the pressure detection mechanism 4 includes an underground pressure detection structure 42, which further includes a signal transmission optical cable 421 and multiple fiber optic pressure gauges 422. The multiple fiber optic pressure gauges 422 are connected in series with the signal transmission optical cable 421 and are correspondingly distributed within multiple deformation sections 14. The pressure data of the deformation cavity 11 includes the pressure data of each deformation sub-cavity 111. The fiber optic demodulator 6 also has at least one pressure fiber optic demodulation module, which is electrically connected to the signal transmission optical cable 421 and can demodulate the optical signals of each fiber optic pressure gauge 422 into pressure data of each deformation sub-cavity 111. By setting multiple fiber optic pressure gauges 422 to measure the pressure of each deformation sub-cavity 111 respectively, it is beneficial to more accurately measure the mechanical parameters of different layers of the rock and soil mass 100 surrounding each deformation section 14. In one embodiment, pressure-circumferential strain curves for corresponding layers are plotted based on the pressure data of each deformation sub-cavity 111 and the circumferential strain of each deformation segment 14. The slope of the linear segment of each curve is then calculated, which is the shear modulus of each layer of the soil mass 100. G .

[0050] Specifically, multiple fiber optic pressure gauges 422 can be suspended inside the flow channel via signal transmission optical cables 421, or they can be attached to the inner or outer wall of the flow channel. Installation is simple and they can accurately measure the pressure of each deformable sub-cavity 111. Alternatively, they can be directly suspended inside the deformable cavity 11 or attached to the inner wall of the elastic tube 15. The pressure fiber optic demodulation module can be an existing Bragg grating center wavelength drift demodulation module or a Fabry-Pérot cavity interferometry demodulation module.

[0051] like Figure 1 and Figure 2As shown, in some other embodiments of the present invention, the pressure detection mechanism 4 includes a ground pressure detection structure 41. The ground pressure detection structure 41 includes an output pressure detection element 411, a low-pressure detection element 412, a medium-pressure detection element 413, a high-pressure detection element 414, and an input pressure detection element 415. The input pressure detection element 415 is located at the input end of the pressure control pipeline 21, and the output pressure detection element 411 is located at the output section of the pressure control pipeline 21. The low-pressure detection element 412, the medium-pressure detection element 413, and the high-pressure detection element 414 are connected in parallel on the pressure control pipeline 21. Specifically, the low-pressure detector 412, medium-pressure detector 413, and high-pressure detector 414 are connected in parallel on the intermediate pipe of the pressure control pipeline 21. The low-pressure detector 412, medium-pressure detector 413, and high-pressure detector 414 have different ranges, so that the corresponding pipeline can be selected to connect the input pipe and the output pipe as needed, and the pressure in the intermediate pipe is measured by the pressure detector of the corresponding range. For example, the greater the strength of the soil and rock mass 100, the greater the pressure of the pressure fluid injected into the elastic sleeve 1 is required to cause a certain deformation of the elastic sleeve 1 and the soil and rock mass 100; conversely, the smaller the strength of the soil and rock mass 100, the smaller the pressure of the pressure fluid injected into the elastic sleeve 1. In this embodiment, the output pressure detector 411, low-pressure detector 412, medium-pressure detector 413, high-pressure detector 414, and input pressure detector 415 are all air pressure gauges.

[0052] In summary, the geotechnical mechanical parameter measurement system of the present invention has at least the following beneficial effects: I. The rock and soil mechanical parameter measurement system of the present invention simplifies the components and eliminates the need for a volume measurement device to analyze and determine the deformation data of the elastic sleeve 1 based on the volume change of the elastic sleeve 1, thereby reducing the overall volume of the device. II. The soil and rock mechanical parameter measurement system of the present invention can be used as a distributed and permanent measurement system for the mechanical safety of soil and rock mass 100, and can also measure the deformation modulus, shear modulus and other mechanical parameters of the entire cross section (depth) of soil and rock mass 100. Third, the rock and soil mechanical parameter measurement system of the present invention can simultaneously analyze the deformation of the entire cross section of the rock and soil mass 100 and obtain mechanical parameters in one measurement. It can also be used as a long-term measurement system to track the dynamic evolution characteristics of the mechanical properties of the rock and soil mass 100. IV. The geotechnical mechanical parameter measurement system of the present invention is applicable to various engineering scenarios and construction processes such as pre-drilling, self-drilling, press-in and pre-embedded methods. Fifth, the geotechnical mechanical parameter measurement system of the present invention has excellent geometric linearity, better meets the conditions of plane strain, and provides more accurate measurement results; VI. The rock and soil mechanical parameter measurement system of the present invention can not only measure deformation, but also the pressure and strain feedback results during the measurement process can be used for hole formation quality evaluation. VII. The geomechanical parameter measurement system of the present invention can accurately record the target layer and the temperature during operation, and filter out the influence of temperature effect on the measurement results; 8. The geotechnical mechanical parameter measurement system of the present invention does not require a multi-layer structure for the measurement mechanism, resulting in a lower accident rate.

[0053] Implementation Method 2

[0054] The present invention also provides a method for measuring the mechanical parameters of soil and rock, which can be implemented using the soil and rock mechanical parameter measurement system in Embodiment 1.

[0055] The method for measuring the mechanical parameters of soil and rock mass of the present invention includes the following steps: implantation: implanting an elastic sleeve 1 with a sensing optical cable 5 installed into the soil and rock mass 100; wherein the sensing optical cable 5 is distributed along the axial direction of the elastic sleeve 1 and contacts the elastic sleeve 1; loading: injecting pressurized fluid into the deformation cavity 11 of the elastic sleeve 1 to expand the elastic sleeve 1; unloading: discharging the pressurized fluid in the deformation cavity 11 to retract the elastic sleeve 1; data acquisition: during the loading and unloading steps, the pressure detection mechanism 4 acquires the pressure data of the deformation cavity 11, and the fiber optic demodulator 6 demodulates the optical signal of the sensing optical cable 5 into optical cable measurement data; data analysis: analyzing and processing the pressure data and fiber optic measurement data to generate the mechanical parameters of the soil and rock mass 100.

[0056] In this embodiment of the invention, the sensing optical cable 5 includes a temperature sensing optical fiber 52 and a strain sensing optical fiber 51; the optical cable measurement data includes the temperature measurement results and strain measurement results of the sensing optical cable 5; the mechanical parameters include the shear modulus of the soil-rock mass 100; the data analysis step specifically includes the following steps: analyzing and processing the temperature measurement results and strain results to generate the circumferential strain of the elastic sleeve 1; analyzing and processing the circumferential strain and pressure data to plot the pressure-circumferential strain curve; selecting the linear segment of the pressure-circumferential strain curve, and then calculating the shear modulus of the soil-rock mass 100; wherein, the shear modulus of the soil-rock mass 100 is the slope of the linear segment. Specifically, during the loading step, pressure data, temperature measurement results, and strain measurement results are continuously collected and analyzed to generate the corresponding circumferential strain, and then the circumferential strain of the elastic sleeve 1 is plotted as a function of the pressure in the deformation cavity 11, i.e., the pressure-circumferential strain curve, based on the pressure data and circumferential strain; then the unloading step is executed.

[0057] In embodiments of the present invention, the mechanical parameters also include the deformation modulus of the soil-rock mass 100; the data analysis step further includes: generating the deformation modulus of the soil-rock mass 100 based on shear modulus analysis.

[0058] The above descriptions are merely a few embodiments of the present invention. Those skilled in the art can make various modifications or variations to the embodiments of the present invention based on the content disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A system for measuring the mechanical parameters of soil and rock masses, characterized in that, include: An elastic sleeve is used for implantation into rock and soil, and the elastic sleeve has a deformation cavity inside; The sensing optical cable is distributed along the axial direction of the elastic sleeve and is in contact with the elastic sleeve; The fiber optic demodulator is electrically connected to the sensing optical cable and can demodulate and process the optical signal of the sensing optical cable to generate optical cable measurement data. A pressure source is used to provide pressurized fluid; A pressure control structure, wherein the pressure source can be connected to the deformation cavity through the pressure control structure; A pressure detection mechanism is used to collect pressure data from the deformation cavity; A data analysis unit is used to analyze and process the pressure data and the optical cable measurement data to generate the mechanical parameters of the soil and rock mass.

2. The soil and rock mechanical parameter measurement system as described in claim 1, characterized in that, The sensing optical cable is spirally wound around the inner wall or inside the elastic sleeve along the axial direction of the elastic sleeve.

3. The rock and soil mechanical parameter measurement system as described in claim 2, characterized in that, The sensing optical cable and the elastic sleeve have an included angle in the radial direction, and the included angle is less than 5 degrees.

4. The soil and rock mechanical parameter measurement system as described in any one of claims 1-3, characterized in that, The optical cable measurement data includes the temperature measurement results and strain measurement results of the sensing optical cable; The sensing optical cable is a composite sensing optical cable; The composite sensing optical cable has a temperature sensing optical fiber and a strain sensing optical fiber. The fiber optic demodulator is a composite fiber optic demodulator, which includes at least one temperature fiber optic demodulation module and at least one strain fiber optic demodulation module. The temperature fiber optic demodulation module is electrically connected to the temperature sensing fiber and can demodulate the optical signal of the temperature sensing fiber into the temperature measurement result. The strain fiber optic demodulation module is electrically connected to the strain sensing fiber and can demodulate the optical signal of the strain sensing fiber into the strain measurement result.

5. The rock and soil mechanical parameter measurement system as described in claim 1, characterized in that, The elastic sleeve is further provided with a flow structure and multiple sealing structures. The flow structure passes through the elastic sleeve along the axial direction and has an annular space between it and the elastic sleeve. The annular space constitutes the deformation cavity. The multiple sealing structures are arranged at intervals along the axial direction of the deformation cavity and divide the elastic sleeve into multiple deformation segments. The deformation cavity is divided into multiple deformation sub-cavities. Each deformation sub-cavity is connected to the pressure control structure through the flow structure.

6. The rock and soil mechanical parameter measurement system as described in claim 5, characterized in that, The pressure detection mechanism includes an underground pressure detection structure, which further includes a signal transmission optical cable and multiple fiber optic pressure gauges. The multiple fiber optic pressure gauges are connected in series on the signal transmission optical cable and are correspondingly distributed in the multiple deformation sections. The pressure data of the deformable cavity includes the pressure data of each of the deformable sub-cavities; the fiber optic demodulator also has at least one pressure fiber optic demodulation module, which is electrically connected to the signal transmission optical cable and can demodulate the optical signals of each of the fiber optic pressure gauges into pressure data of each of the deformable sub-cavities.

7. The rock and soil mechanical parameter measurement system as described in claim 5, characterized in that, The flow structure includes a flow pipe with multiple through holes arranged on it, and the flow pipe connects to each of the deformable sub-cavities through the multiple through holes.

8. The rock and soil mechanical parameter measurement system as described in claim 1, characterized in that, The pressure control structure includes a pressure control pipeline, a pressure reducing valve, a regulating valve, and a pressure relief valve. The pressure control pipeline connects the pressure source and the deformation cavity, and the pressure reducing valve, the regulating valve, and the pressure relief valve are installed on the pressure control pipeline.

9. The soil and rock mechanical parameter measurement system as described in claim 8, characterized in that, The pressure detection mechanism includes a ground pressure detection structure, which includes an output pressure detection element, a low-pressure detection element, a medium-pressure detection element, a high-pressure detection element, and an input pressure detection element. The input pressure detection element is located at the input end of the pressure control pipeline, and the output pressure detection element is located at the output section of the pressure control pipeline. The low-pressure detection element, the medium-pressure detection element, and the high-pressure detection element are connected in parallel on the pressure control pipeline.

10. A method for measuring the mechanical parameters of rock and soil, characterized in that, Includes the following steps: Implantation: An elastic sleeve with a sensing optical cable installed is implanted into the rock and soil; wherein the sensing optical cable is distributed along the axial direction of the elastic sleeve and is in contact with the elastic sleeve; Loading: Injecting pressurized fluid into the deformation cavity of the elastic sleeve to cause the elastic sleeve to expand; Unloading: The pressurized fluid in the deformation cavity is discharged, causing the elastic sleeve to retract; Data acquisition: During the loading and unloading steps, the pressure detection mechanism acquires the pressure data of the deformation cavity, and the fiber optic demodulator demodulates the optical signal of the sensing optical cable into optical cable measurement data. Data analysis: The mechanical parameters of the soil and rock mass are obtained by analyzing and processing the pressure data and the fiber optic measurement data.

11. The method for measuring the mechanical parameters of soil and rock mass as described in claim 10, characterized in that, The sensing optical cable includes a temperature sensing fiber and a strain sensing fiber; the measurement data of the optical cable includes the temperature measurement results and strain measurement results of the sensing optical cable; the mechanical parameters include the shear modulus of the rock and soil mass; the data analysis steps specifically include the following steps: The circumferential strain of the elastic sleeve is generated based on the temperature measurement results and the strain measurement results. Plot a pressure-circumferential strain curve based on the circumferential strain and pressure data; Select the linear segment of the pressure-circumferential strain curve, and then calculate the shear modulus of the soil and rock mass; wherein, the shear modulus of the soil and rock mass is the slope of the linear segment.

12. The method for measuring the mechanical parameters of soil and rock as described in claim 11, characterized in that, The mechanical parameters also include the deformation modulus of the soil and rock mass; the data analysis step further includes: generating the deformation modulus of the soil and rock mass based on the shear modulus analysis.

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