CN-121980751-A - Structural surface shearing damage model under synergistic effect of freezing and thawing cycle and compression shear load

CN121980751ACN 121980751 ACN121980751 ACN 121980751ACN-121980751-A

Abstract

The application provides a structural surface shearing damage model under the synergistic effect of freezing and thawing cycle and compression shear load, which is In the above-mentioned steps, Is normal stress; Is the basic friction angle; is a characteristic angle; uniaxial compressive strength to account for freeze-thaw cycles; Is fit parameter, characteristic angle The critical inclination angle corresponding to the contact area ratio of the windward side and the shearing side is 1/e. The application mainly adopts the characteristic angle lambda to measure the rough characteristic of the structural surface, and provides a new model based on the characteristic angle lambda, which can well represent the relation between the critical visual inclination angle and the potential contact area, and compared with GRASSELLI model and JRC-JCS model, the new model has obvious advantages in the aspects of prediction precision and conciseness. Compared with GRASSELLI morphology characterization methods, the novel model gathers potential contact areas on the windward side, eliminates the maximum visual inclination angle with unstable value, has better fitting effect and avoids the difficult problem of multi-parameter combination.

Inventors

TIAN YONGCHAO
SUN LEI
JI JIE
MAO YANQI
ZHU JIE
LIU QUANSHENG
LI ZHENHUA
TANG ZHICHENG
GUO JIAQI
CHEN XU
LIU HE

Assignees

河南理工大学

Dates

Publication Date: 20260505
Application Date: 20251218

Claims (9)

1. A structural surface shearing damage model under the synergistic effect of freeze thawing cycle and compression shear load is characterized in that the structural surface shearing strength of the freeze thawing cycle times is considered The method comprises the following steps: ; In the above-mentioned method, the step of, Is normal stress; Is the basic friction angle; is a characteristic angle; uniaxial compressive strength to account for freeze-thaw cycles; fitting parameters; Characteristic angle In a quantized model of critical view angle-contact area ratio of windward and shearing sides of a structural surface constructed based on a Weibull distribution function, the critical view angle corresponding to the contact area ratio of the windward and shearing sides is 1/e, and e is a natural constant.
2. The method for constructing a shear failure model under the synergistic effect of freeze thawing cycle and compressive shear load according to claim 1, wherein the characteristic angle is The calculation formula is as follows: ; In the above-mentioned method, the step of, Representing the contact area ratio of the shearing facing side of the structural surface; for fitting parameters, the shape parameters of the Weibull distribution are represented, and the type of attenuation is controlled; Representing the critical viewing angle.
3. The method for constructing a shear failure model under the synergistic effect of freeze thawing cycle and compression shear load according to claim 1, wherein the value range of the fitting parameter k is 1.21-1.39.
4. The freeze-thaw cycle and compression shear load synergistic effect structural plane shear failure model of claim 1, wherein: the function is calculated for the uniaxial compressive strength of the rock wall after being corrected by considering the freeze thawing cycle times: ; in the formula, N is the number of freeze thawing cycles; is the uniaxial compressive strength of the rock wall when not subjected to freeze-thawing cycles, i.e. the uniaxial compressive strength in the natural state.
5. The method for constructing the structural surface shear failure model under the synergistic effect of the freeze-thawing cycle and the compressive shear load according to claim 1 is characterized by comprising the following steps of: firstly, manufacturing a plurality of groups of structural surface samples with consistent morphology, acquiring at least 30 groups of structural surface point clouds with different roughness by adopting a three-dimensional laser scanning technology, converting a microprotrusion body into a triangular grid unit, acquiring structural surface contact area ratio data under grid visual inclination angles, areas and different critical visual inclination angles, and constructing a critical visual inclination angle-contact area ratio quantization model based on a Weibull distribution function; performing freeze thawing cycle tests on the structural surface samples, wherein the freeze thawing cycle times are not less than 30 times, and performing uniaxial compression, brazilian split, triaxial compression and direct shear tests on the same sample after freeze thawing for 0, 10, 20 and 30 times respectively to obtain measurement data of uniaxial compression strength, internal friction angle, structural surface peak shear strength and normal stress under different freeze thawing cycle times; Step three, defining and solving characteristic angles according to the critical inclination angle-contact area ratio quantization model constructed in the step one ; Fourth, analyzing the relation between the data and based on the Patton model Determining the form of the increment term i by nonlinear fitting , Substituting the parameters into the Patton model to obtain the final model 。
6. The method for modeling structural surface shear failure under the synergistic effect of freeze thawing cycle and compressive shear load according to claim 5, wherein the critical inclination angle-contact area ratio quantization model constructed in the first step is as follows: ; In the above-mentioned method, the step of, Representing the contact area ratio of the windward side; Is a characteristic angle, and represents a contact area ratio of The critical angle corresponding to the time; a scale parameter representing the weibull distribution, controlling the rate of decay; for fitting parameters, the shape parameters of the Weibull distribution are represented, and the type of attenuation is controlled; Represents the critical viewing angle and ln is the operator of natural logarithm.
7. The method for constructing a structural surface shear failure model under the synergistic effect of freeze thawing cycle and compressive shear load according to claim 5, wherein in the first step, the structural surface sample is prepared as follows: Firstly, carrying out a splitting test on cubic rock samples with the dimensions of 100mm multiplied by 100mm by using a rock mechanical test system, and screening four groups of rock samples with obvious roughness difference from the cubic rock samples; Then, carrying out three-dimensional laser scanning on the four rock samples by using a three-dimensional scanner, wherein the obtained point cloud data are used for constructing a three-dimensional geometric model; And finally, writing an engraving path program based on the three-dimensional geometric model, and manufacturing structural surface samples with four kinds of roughness through a numerical control engraving machine.
8. The method for modeling structural surface shear failure under the synergistic effect of freeze thawing cycle and compressive shear load according to claim 5, wherein in the second step, the step of freeze thawing cycle test comprises: firstly, drying a structural surface sample and 105 ℃ in a constant-temperature blast drying oven for 24 hours to constant weight; secondly, placing the dried sample in a vacuum pressurizing and saturating device, vacuumizing for 4-6 hours, pressurizing and saturating for 24 hours, setting the pressurizing value to be 0.1MPa, and obtaining the pressurized and saturated sample by using distilled water as a saturated solution; The third step, the sample after pressurized saturation is sealed by a preservative film and put into a high-low temperature test box for freeze thawing cycle, wherein the cycle time of the freeze thawing cycle is 8 hours, and the cycle time of the freeze thawing cycle is (1) a cooling stage, wherein the temperature is reduced to-20 ℃ from the initial temperature of 20 ℃ for 1.5 hours, (2) a freezing stage, the temperature is maintained at-20 ℃ for 2.5 hours, (3) a heating stage, the temperature is increased to 20 ℃ from-20 ℃ for 1.5 hours, and (4) a dissolving stage, the temperature is maintained at 20 ℃ for 2.5 hours.
9. The freeze-thaw cycle and compression shear load synergistic effect structural plane shear failure model of claim 5, wherein: The verification method of the model comprises the following steps: Selecting at least 10 groups of independent structural surface samples, and repeating the freeze-thawing cycle and uniaxial compression, brazilian split, triaxial compression and direct shear test of the second step to obtain measurement data of uniaxial compressive strength, internal friction angle and normal stress under different freeze-thawing cycle times and structural surface peak shear strength actual measurement values for verification; Substituting the data into a structural surface shearing damage model under the synergistic effect of the freeze thawing cycle and the compressive shear load, and calculating a predicted value of the structural surface peak shearing strength; And comparing the actual measurement value of the structural plane peak shear strength with the predicted value of the structural plane peak shear strength, and evaluating and analyzing by using the index average relative error and the determination coefficient R 2 .

Description

Structural surface shearing damage model under synergistic effect of freezing and thawing cycle and compression shear load Technical Field The application relates to the technical field of rock mass structural surface shearing strength prediction, in particular to a structural surface shearing damage model under the synergistic effect of freezing and thawing cycle and compression shear load. Background The rock mass in the cold region often generates a structural plane sliding disaster, serious casualties and economic losses are caused, and the compression shear damage mechanism of the structural plane under the freeze thawing cycle is disclosed to be a key point for effectively restraining the occurrence of the type of disaster. The JRC-JCS model (Barton and Choubey 1977) and the GRASSELLI model (GRASSELLI 2006) are two classical models for researching the mechanical characteristics of the structural surface of a rock mass, and are widely paid attention to students at home and abroad. However, they have the following drawbacks in cold zone structural plane shear strength prediction: (1) The key parameters are mostly obtained based on normal-temperature drying or water saturation conditions, and the deterioration rule of parameters caused by uncorrelated freeze thawing times is that the uniaxial compressive strength of unfrozen rock mass is taken by default in a JCS (joint casting) model of RC-JCS. (2) The model parameters are difficult to obtain in practice, for example GRASSELLI the model needs to pass through the maximum contact area ratioMaximum viewing angleFitting parametersTo measure the relationship between the inclination of the microprotrusions and the potential contact areaThe variation range is small and the method has the advantages of low cost,The influence of scanning noise is large, so that the parameter acquisition difficulty in engineering application is high and the prediction error is high. (3) The depiction of the potential contact area does not conform to the actual shear mechanism, such as uniform distribution of default roughness of the JRC-JCS model, but in practice structural surface damage is mainly concentrated on the shearing facing side, and the asperities that are relatively rough on the shearing facing side bear the main shear load. Therefore, there is a need to provide an improved technical solution for the above-mentioned deficiencies of the prior art, which can attach to the freeze thawing scene of the rock mass in the cold region and the freeze thawing degradation rule of the rock mass in the real cold region, and the key parameters are easy to obtain. Disclosure of Invention The application aims to provide a structural surface shearing damage model under the synergistic effect of freezing and thawing cycle and compression shear load so as to solve or alleviate the problems in the prior art. In order to achieve the above object, the present application provides the following technical solutions: The application provides a structural surface shear damage model under the synergistic effect of freeze thawing cycle and compression shear load, which considers the structural surface shear strength of freeze thawing cycle times The method comprises the following steps: ; In the above-mentioned method, the step of, Is normal stress; Is the basic friction angle; is a characteristic angle; uniaxial compressive strength to account for freeze-thaw cycles; fitting parameters; Characteristic angle In a quantized model of critical view angle-contact area ratio of windward and shearing sides of a structural surface constructed based on a Weibull distribution function, the critical view angle corresponding to the contact area ratio of the windward and shearing sides is 1/e, and e is a natural constant. Further, the characteristic angleThe calculation formula is as follows: ; In the above-mentioned method, the step of, Representing the contact area ratio of the shearing facing side of the structural surface; for fitting parameters, the shape parameters of the Weibull distribution are represented, and the type of attenuation is controlled; Representing the critical viewing angle. Further, the value range of the fitting parameter k is 1.21-1.39. Further, the method comprises the steps of,The function is calculated for the uniaxial compressive strength of the rock wall after being corrected by considering the freeze thawing cycle times: ; in the formula, N is the number of freeze thawing cycles; is the uniaxial compressive strength of the rock wall when not subjected to freeze-thawing cycles, i.e. the uniaxial compressive strength in the natural state. Further, the construction of the structural surface shear damage model under the synergistic effect of the freeze thawing cycle and the compression shear load comprises the following steps: firstly, manufacturing a plurality of groups of structural surface samples with consistent morphology, acquiring at least 30 groups of structural surfa