A method for obtaining shear strength of ice-rock interface

Abstract

This invention relates to the field of freeze-thaw rock measurement technology, specifically to a method for obtaining the shear strength of the ice-rock interface. The method includes the following steps: obtaining the length of the rough interface, the height of the rough interface, the roughness coefficient of the rock joint surface, the freezing temperature, the uniaxial compressive strength of the ice, the normal stress of the ice-rock interface, and the uniaxial compressive strength of the rock; obtaining the shear stress generated by the bonding effect of the ice-rock interface based on the length of the rough interface, the height of the rough interface, and the freezing temperature; obtaining the shear stress generated by the ice-rock interface hindering sliding based on the freezing temperature, the uniaxial compressive strength of the ice, the normal stress, and the uniaxial compressive strength of the rock; and obtaining the shear strength of the ice-rock interface based on the shear stress generated by the bonding effect of the ice-rock interface and the shear stress generated by the ice-rock interface hindering sliding. This method solves the problem in existing technologies where obtaining the shear strength parameters of the ice-rock interface through on-site experiments is difficult due to limitations in on-site conditions and sampling equipment.

Description

Technical Field

[0001] This invention relates to the field of freeze-thaw rock measurement technology, specifically to a method for obtaining the shear strength of the ice-rock interface. Background Technology

[0002] Measuring the shear strength of the ice-rock interface is of great significance for engineering in cold regions, especially for rock slope collapse and tunnel frost heave cracking in high-altitude and cold areas. The ice-rock interface refers to the interface between ice and rock. The shear strength of the ice-rock interface is an important geotechnical parameter in high-altitude and cold regions.

[0003] However, there are currently no experimental studies specifically designed for ice-rock interface strength, and parameters related to the shear strength of the ice-rock interface are extremely scarce. Obtaining ice-rock interface samples in the field is extremely difficult. Under field conditions, ice-rock interface samples may melt or break due to limitations in field conditions and sampling equipment, making it virtually impossible to obtain ice-rock interface shear strength parameters in the field. Furthermore, measuring the shear strength of the ice-rock interface in the laboratory is subject to strict limitations on sample preparation, loading season temperature, experimental equipment, and operation, making it extremely difficult to obtain the shear strength of the ice-rock interface. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for obtaining the shear strength of the ice-rock interface, which solves the problem that obtaining the shear strength parameters of the ice-rock interface through field experiments is difficult due to limitations in field conditions and sampling equipment.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] This invention provides a method for obtaining the shear strength of the ice-rock interface, comprising the following steps:

[0007] Obtain the length and height of the rough interface between ice and rock, the roughness coefficient of the rock joint surface, the freezing temperature, the uniaxial compressive strength of ice, the normal stress of the ice-rock interface, and the uniaxial compressive strength of rock.

[0008] The shear stress generated by the bonding effect of the ice-rock interface is obtained based on the length and height of the rough interface and the freezing temperature.

[0009] Based on the freezing temperature, the uniaxial compressive strength of ice, the normal stress at the ice-rock interface, and the uniaxial compressive strength of rock, the shear stress generated at the ice-rock interface that hinders sliding is obtained.

[0010] The shear strength of the ice-rock interface is obtained based on the shear stress generated by the bonding effect at the ice-rock interface and the shear stress generated by the ice-rock interface hindering sliding.

[0011] In some alternative solutions, determining the shear stress at the ice-rock interface that hinders sliding, based on the freezing temperature, the uniaxial compressive strength of the ice, the normal stress at the ice-rock interface, and the uniaxial compressive strength of the rock, includes:

[0012] Determine the internal friction angle of the ice based on the freezing temperature;

[0013] Based on the internal friction angle of ice, the uniaxial compressive strength of ice, the normal stress at the ice-rock interface, and the uniaxial compressive strength of rock, the shear stress generated at the ice-rock interface that hinders sliding is obtained.

[0014] In some alternative solutions, according to the formula Determine the internal friction angle of ice. φ ,in, This is the freezing temperature. The absolute zero is 273.1 K. e is the base of the natural logarithm.

[0015] In some alternative solutions, according to the formula The shear stress generated at the ice-rock interface that hinders sliding was calculated. p ,in, φ Let be the internal friction angle of ice. The normal stress at the ice-rock interface. JRC The roughness coefficient of the rock joint surface. Ice surface strength Rock joint surface strength , This refers to the uniaxial compressive strength of ice. It represents the uniaxial compressive strength of the rock.

[0016] In some alternative solutions, the uniaxial compressive strength It is calculated based on empirical formulas or measured by uniaxial compressive strength tests.

[0017] In some alternative solutions, the empirical formula is: ,in T ( k () represents the freezing temperature.

[0018] In some alternative solutions, the uniaxial compressive strength of the rock is obtained by matching the rock type or by measuring the uniaxial compressive strength through a test.

[0019] In some alternative solutions, the method of obtaining the shear stress generated by the bonding effect of the ice-rock interface based on the length of the rough interface, the height of the rough interface, and the freezing temperature includes:

[0020] According to the formula The shear stress generated by the bonding effect at the ice-rock interface was calculated. c , The length of the rough interface between the ice and rock surfaces. For rough interface height, This represents the difference between the freezing temperature and zero degrees Celsius.

[0021] In some alternative solutions, according to the formula The shear strength of the ice-rock interface was calculated. ,in, p The shear stress generated at the ice-rock interface hinders sliding. c This refers to the shear stress generated by the bonding effect at the ice-rock interface.

[0022] In some alternative approaches, the normal stress at the ice-rock interface is taken from the rock geostress.

[0023] Compared with existing technologies, the advantages of this invention are as follows: The method described in this application only requires the length and height of the rough interface between the ice and rock surfaces, the roughness coefficient of the rock joint surface, the freezing temperature, the uniaxial compressive strength of the ice, the normal stress of the ice-rock interface, and the uniaxial compressive strength of the rock to quickly calculate the corresponding interfacial shear strength. The shear stress generated by the bonding effect of the ice-rock interface is obtained based on the length, height, and freezing temperature of the rough interface; and the shear stress generated by the ice-rock interface hindering sliding is obtained based on the freezing temperature, the uniaxial compressive strength of the ice, the normal stress of the ice-rock interface, and the uniaxial compressive strength of the rock. Finally, the shear strength of the ice-rock interface is obtained based on the shear stress generated by the bonding effect and the shear stress generated by the ice-rock interface hindering sliding. This allows for the rapid on-site determination of the ice-rock interface shear strength parameters based on relevant parameters, serving cold-region engineering projects. It eliminates the need to obtain ice-rock interface samples under on-site conditions. Furthermore, comparison of theoretical calculation results and experimental data reveals that the error between the theoretical calculation results and experimental data is very small, making them suitable as a basis for theoretical calculations. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart illustrating the method for obtaining the shear strength of the ice-rock interface in an embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram comparing the theoretically calculated roughness results with the experimental values ​​in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram comparing the theoretically calculated temperature results with the experimental values ​​in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram comparing the theoretically calculated normal stress with the experimental value in an embodiment of the present invention. Detailed Implementation

[0029] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0030] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] Figure 1 This is a flowchart of the method for obtaining the shear strength of the ice-rock interface in an embodiment of the present invention, as shown below. Figure 1 As shown, this invention provides a method for obtaining the shear strength of the ice-rock interface, comprising the following steps:

[0032] S1: Obtain the length of the rough interface between ice and rock, the height of the rough interface, the roughness coefficient of the rock joint surface, the freezing temperature, the uniaxial compressive strength of ice, the normal stress of the ice-rock interface, and the uniaxial compressive strength of rock.

[0033] In some alternative embodiments, uniaxial compressive strength It is calculated based on empirical formulas or measured by uniaxial compressive strength tests.

[0034] Uniaxial compressive strength When calculating based on empirical formulas, the empirical formula used is: ,in T ( k The value is the freezing temperature. It was obtained from the literature (Shen Letian et al., 1990).

[0035] The uniaxial compressive strength of rock can be obtained by matching the rock type or by measuring the uniaxial compressive strength through a uniaxial compressive strength test.

[0036] In this example, the experiment showed that the uniaxial compressive strength of red sandstone is temperature-dependent; within the range of 0-50℃, the uniaxial compressive strength of red sandstone ranges from 90-100 MPa. In practical applications, the uniaxial compressive strength of the rock can be obtained through experiments.

[0037] Furthermore, the normal stress at the ice-rock interface is based on the principal stresses of the environment in which the ice-rock interface is located. The roughness coefficient of the rock joint surface... JRC The calculation method can be obtained by directly consulting the literature.

[0038] In addition, the length of the rough interface, the height of the rough interface, and the freezing temperature between the ice and rock interfaces were obtained based on actual on-site measurements.

[0039] Based on ice-rock interface experiments, the shear stress at the ice-rock interface can be expressed as: .in, p This refers to the shear stress that hinders sliding caused by the rough interface. c For the bonding force at the ice-rock interface, This refers to the shear strength of the ice-rock interface, i.e., the shear stress.

[0040] S2: Based on the length of the rough interface, the height of the rough interface, and the freezing temperature, the shear stress generated by the bonding effect of the ice-rock interface is obtained.

[0041] In this embodiment, the shear stress generated at the ice-rock interface due to bonding can be expressed as:

[0042]

[0043] The interfacial element force can be replaced by the strength of ice in the transition zone at the interface. Nix and Gao obtained the shear strength of the mesoscale element based on gradient plasticity theory and dislocation theory of material microstructure. The shear stress generated by bonding can be expressed by the shear strength of the mesoscale element.

[0044]

[0045] in, adh For ice-rock bonding stress, S It is a curved surface at the junction of ice and rock. A This represents the projected area of ​​the ice-rock interface.

[0046] The cohesive force across the entire ice-rock interface can be expressed as a surface integral:

[0047]

[0048] in, F For the adhesion force at the ice-rock interface, The length of the rough interface between the ice and rock surfaces. For rough interface height, b This represents the width of the interface.

[0049] According to Vyalow's research, adhesive force can be expressed as:

[0050]

[0051] The derivation of the initial viscosity can be simplified to:

[0052]

[0053] in, B It is a constant. adh0 The initial bonding stress at the ice-rock interface, The difference between the freezing temperature and zero degrees Celsius. For parameters related to temperature, This is the solidification temperature. As the reference temperature, For surface tension, The molecular distance between the ice and the connecting material. The surface contact angle, The proportion of ice in contact with the matrix, This is the freezing temperature.

[0054] In theoretical calculations, most parameters are microscopic, and it is difficult to obtain all microscopic parameters experimentally. Based on experimental data from references, the following empirical formula is used to replace the ice-rock bond strength:

[0055]

[0056] Based on the above analysis, in step S: according to the formula The shear stress generated by the bonding effect at the ice-rock interface was calculated. c , The length of the rough interface between the ice and rock surfaces. For the roughness of the interface height and the freezing temperature, This represents the difference between the freezing temperature and zero degrees Celsius.

[0057] S3: Based on the freezing temperature, the uniaxial compressive strength of ice, the normal stress at the ice-rock interface, and the uniaxial compressive strength of rock, the shear stress generated at the ice-rock interface that hinders sliding is obtained.

[0058] The shear stress at the interface that hinders sliding is mainly calculated using the Mohr-Coulomb principle:

[0059]

[0060] Barton later developed an improved form through extensive experimentation, which was recognized by the International Society for Rock Mechanics.

[0061]

[0062] Where: correction value , The normal stress at the ice-rock interface. Let be the internal friction angle of ice. The roughness coefficient of the rock joint surface. JCS It represents the interfacial compressive strength.

[0063] This theory applies when the materials on both sides of the interface are identical. For different materials on both sides of the interface, Zhang Huiya proposed a modified formula:

[0064]

[0065]

[0066] in, For the surface strength of ice joints, For the strength of rock joint surfaces, This refers to the uniaxial compressive strength of ice. It represents the uniaxial compressive strength of the rock.

[0067] The shear stress generated at the interface that hinders relative sliding is expressed as:

[0068]

[0069] In the formula, JRC is the roughness coefficient of the rock joint surface.

[0070] The internal friction angle of ice is related to temperature and can be represented by two components:

[0071]

[0072] The increase in internal friction angle at a certain freezing temperature is temperature-dependent and can be expressed as:

[0073]

[0074] It is a constant, which can be obtained from the above two equations:

[0075]

[0076] Based on relevant experimental data from Fish, the following calculations were performed: ,

[0077]

[0078] Right now:

[0079]

[0080] Based on the above analysis, step S3 includes:

[0081] S31: Determine the internal friction angle of ice based on the freezing temperature.

[0082] Specifically, according to the formula Determine the internal friction angle of ice. φ ,in, This is the freezing temperature. The absolute zero is 273.1 K. e is the base of the natural logarithm.

[0083] S32: Based on the internal friction angle of ice, the uniaxial compressive strength of ice, the normal stress at the ice-rock interface, and the uniaxial compressive strength of rock, the shear stress generated by the ice-rock interface that hinders sliding is obtained.

[0084] According to the formula The shear stress generated at the ice-rock interface that hinders sliding was calculated. p ,in, φ Let be the internal friction angle of ice. The normal stress at the ice-rock interface, Ice surface strength Rock joint surface strength , This refers to the uniaxial compressive strength of ice. It represents the uniaxial compressive strength of the rock.

[0085] S4: The shear strength of the ice-rock interface is obtained based on the shear stress generated by the bonding effect at the ice-rock interface and the shear stress generated by the ice-rock interface hindering sliding.

[0086] In this example, according to the formula The shear strength of the ice-rock interface was calculated. ,in, p The shear stress generated at the ice-rock interface hinders sliding. c This refers to the shear stress generated by the bonding effect at the ice-rock interface.

[0087] Based on the above derivation, p and c Substitute the expression into the formula In the process, the theoretical expression for the shear strength of the ice-rock interface, derived from the microscopic derivation, is obtained as follows:

[0088]

[0089] The simplified expression is:

[0090]

[0091] After theoretical derivation, the shear strength of the ice-rock interface under different freezing temperatures, normal forces, and interface roughness conditions was investigated. The experimental results were compared with the theoretical calculation results, and the comparison curves are as follows. Figure 2 , Figure 3 and Figure 4 As shown, the theoretically obtained shear strength curve of the ice-rock interface is within the error range of the experimentally obtained shear strength point of the ice-rock interface.

[0092] In summary, the method described in this application only requires the length and height of the rough interface between the ice and rock surfaces, the roughness coefficient of the rock joint surface, the freezing temperature, the uniaxial compressive strength of the ice, the normal stress at the ice-rock interface, and the uniaxial compressive strength of the rock to quickly calculate the corresponding interfacial shear strength. Furthermore, comparison between the theoretical calculation results and experimental data reveals that the errors are very small. This method enables rapid on-site determination of the ice-rock interface shear strength parameters based on relevant parameters, serving cold-region engineering projects. It eliminates the need to obtain ice-rock interface samples under on-site conditions.

[0093] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0094] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A method for obtaining the shear strength of an ice-rock interface, characterized in that, Includes the following steps: Obtain the length and height of the rough interface between ice and rock, the roughness coefficient of the rock joint surface, the freezing temperature, the uniaxial compressive strength of ice, the normal stress of the ice-rock interface, and the uniaxial compressive strength of rock. The shear stress generated by the bonding effect of the ice-rock interface is obtained based on the length and height of the rough interface and the freezing temperature between the ice and rock interfaces. The method for obtaining the shear stress generated by the bonding effect of the ice-rock interface based on the length of the rough interface, the height of the rough interface, and the freezing temperature includes: According to the formula The shear stress generated by the bonding effect at the ice-rock interface was calculated. c , The length of the rough interface between the ice and rock surfaces. For rough interface height, The difference between the freezing temperature and zero degrees Celsius; Based on the freezing temperature, the uniaxial compressive strength of ice, the normal stress at the ice-rock interface, and the uniaxial compressive strength of rock, the shear stress at the ice-rock interface that hinders sliding is obtained, including: Determine the internal friction angle of the ice based on the freezing temperature; Based on the internal friction angle of ice, the uniaxial compressive strength of ice, the normal stress at the ice-rock interface, and the uniaxial compressive strength of rock, the shear stress generated at the ice-rock interface that hinders sliding is obtained. According to the formula The shear stress generated at the ice-rock interface that hinders sliding was calculated. p ,in, φ Let be the internal friction angle of ice. The normal stress at the ice-rock interface. JRC The roughness coefficient of the rock joint surface. Ice surface strength Rock joint surface strength , This refers to the uniaxial compressive strength of ice. It represents the uniaxial compressive strength of the rock. The shear strength of the ice-rock interface is obtained based on the shear stress generated by the bonding effect at the ice-rock interface and the shear stress generated by the ice-rock interface hindering sliding.

2. The method for obtaining the shear strength of the ice-rock interface as described in claim 1, characterized in that: According to the formula Determine the internal friction angle of ice. φ ,in, This is the freezing temperature. The absolute zero is 273.1 K. e is the base of the natural logarithm.

3. The method for obtaining the shear strength of the ice-rock interface as described in claim 1, characterized in that: The uniaxial compressive strength It is calculated based on empirical formulas or measured by uniaxial compressive strength tests.

4. The method for obtaining the shear strength of the ice-rock interface as described in claim 3, characterized in that: The empirical formula is: ,in T ( k () represents the freezing temperature.

5. The method for obtaining the shear strength of the ice-rock interface as described in claim 1, characterized in that: The uniaxial compressive strength of the rock is obtained by matching the rock type or by measuring the uniaxial compressive strength through a uniaxial compressive strength test.

6. The method for obtaining the shear strength of the ice-rock interface as described in claim 1, characterized in that: According to the formula The shear strength of the ice-rock interface was calculated. ,in, p The shear stress generated at the ice-rock interface hinders sliding. c This refers to the shear stress generated by the bonding effect at the ice-rock interface.

7. The method for obtaining the shear strength of the ice-rock interface as described in claim 1, characterized in that: The normal stress at the ice-rock interface is based on the rock geostress.

Images