A method for predicting the weathering degree of a slope of a surface mine pit

Abstract

This invention provides a method for predicting the weathering degree of open-pit mine slopes. In the field of dynamic weathering degree classification, the method includes: taking samples from the area to be evaluated to prepare multiple rock samples; conducting longitudinal wave velocity tests, uniaxial compression tests, and nitrogen adsorption specific surface area tests on the multiple rock samples; conducting XRD mineral diffraction tests on the multiple rock samples; obtaining a rock weathering degree classification standard based on the weathering grade of the rock samples under longitudinal wave velocity ratio conditions, the weathering grade of the rock samples under peak intensity ratio conditions, the rock porosity of the rock samples, and the rock alteration mineral content of the rock samples; and constructing a spatiotemporal evolution model of the weathering degree of open-pit mine slope rocks using the mining years as the target time series sample to predict the future weathering time and the weathering degree of rocks at the mining location.

Description

Technical Field

[0001] This invention relates to the field of rock weathering evaluation, and more particularly to a method for predicting the weathering degree of open-pit mine slopes. Background Technology

[0002] Open-pit mine slopes are naturally formed rock slopes after mining operations. Open-pit mines are numerous and play a crucial role in mineral resource development, holding significant engineering importance. Exposed to varying environments of air, moisture, and temperature, these slopes are affected by freeze-thaw cycles, temperature changes, and mechanical forces such as blasting vibrations. This causes micro-fractures to form within the rock, gradually leading to rock disintegration. Furthermore, rainwater seeps into the rock pores, reacting chemically with the mineral components through processes like hydrolysis, oxidation, and dissolution. This results in the transformation of mineral components on the rock surface, generating weathering products such as clay minerals and rust. Weathered rock slopes are highly susceptible to landslides, which are characterized by their suddenness, short duration, and difficulty in prevention. These landslides frequently cause significant casualties, economic losses, and disrupt normal mine production. Therefore, accurately classifying the weathering equivalence of rock is crucial for assessing the risk of landslides on open-pit mine slopes.

[0003] Existing technologies often employ qualitative engineering geological methods to classify the weathering degree of rocks on open-pit mine slopes, primarily based on rock mass structure, rock color, and mineral composition. However, this classification method is highly susceptible to human subjectivity, resulting in a high error rate. Furthermore, it cannot predict the future trend of rock weathering, thus hindering timely reinforcement and reducing the timeliness of open-pit mine slope collapse prevention. This issue urgently needs to be addressed. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for predicting the weathering degree of open-pit mine slopes. This method comprehensively considers the size and number of internal rock pores, the content of altered minerals, the peak rock strength, and the P-wave velocity ratio to quantitatively evaluate the weathering grade. Specifically, it includes:

[0005] A method for predicting the weathering degree of open-pit mine slopes includes:

[0006] S1. Take on-site samples from the area to be evaluated and prepare multiple rock samples;

[0007] S2. Perform longitudinal wave velocity tests on multiple rock samples to obtain the weathering grade of the rock samples under the longitudinal wave velocity ratio condition.

[0008] Uniaxial compression tests were conducted on multiple rock samples to obtain the weathering grade of the rock samples under the peak strength ratio condition;

[0009] S3. Perform a nitrogen adsorption specific surface area test on multiple rock samples to obtain the rock porosity of each rock sample;

[0010] XRD mineral diffraction tests were performed on multiple rock samples to obtain the weathering grade of the rock samples based on the content of alteration minerals in the rock.

[0011] S4. Based on the weathering grade of the rock sample under the longitudinal wave velocity ratio condition, the weathering grade of the rock sample under the peak strength ratio condition, the rock porosity of the rock sample, and the rock alteration mineral content of the rock sample, a quantitative calculation method for the weathering degree of open-pit mine slope is constructed, and a rock weathering degree classification standard is obtained.

[0012] S5. Based on the rock weathering degree grading standard, using the mining years as the target time series sample, construct a spatiotemporal evolution model of the rock weathering degree of the open-pit mine slope to predict the future weathering time and the rock weathering degree at the mining location.

[0013] Optionally, the process of S1, which involves taking samples from the area to be evaluated and preparing multiple rock specimens, includes:

[0014] Weathered rocks with different mining exposure times, mining spaces, and lithologies were obtained; the weathering time gradient and vertical depth were determined according to the mining years, the selected areas were marked, and samples were prepared.

[0015] Each of the rock samples is cylindrical, with a diameter of 50 mm and a height of 100 mm. The parallelism and perpendicularity errors at both ends of the rock sample are less than or equal to 0.03 mm.

[0016] Optionally, the weathering grade of the rock sample under the P-wave velocity ratio condition in S2 includes:

[0017] S201. Measure the length and diameter of the rock sample with a graduated ruler, accurate to the millimeter level;

[0018] S202. Coupling agent is evenly applied to both ends of the multiple rock samples. After the wave velocity tester emits sound waves evenly and stably, the test is started. Based on the longitudinal wave velocity of each rock sample, the longitudinal wave velocity ratio β of the rock sample and the fresh rock is calculated to obtain the weathering grade of the rock sample under the longitudinal wave velocity ratio condition.

[0019] The weathering grade classification rules for rock samples under the longitudinal wave velocity ratio condition include:

[0020] When 0.9≤β≤1.0, the current rock sample is the weathering grade of a fresh rock sample;

[0021] When 0.8 ≤ β < 0.9, the current rock sample is a slightly weathered rock sample.

[0022] When 0.6≤β<0.8, the current rock sample is a moderately weathered rock sample.

[0023] When 0.4≤β<0.6, the current rock sample is a strongly weathered rock sample.

[0024] When β < 0.4, the current rock sample is a weathering grade of a completely weathered rock sample.

[0025] Optionally, the weathering grade of the rock samples obtained in step S2 by performing uniaxial compression tests on multiple rock samples and determining the peak strength ratio includes:

[0026] S211. Perform uniaxial compression tests on multiple rock samples respectively to obtain the peak strength of each rock sample;

[0027] S212. Calculate the peak strength ratio R of each rock sample to that of fresh rock. k The weathering grade of the rock sample under the peak strength ratio condition was obtained;

[0028] The weathering grade classification rules for rock samples under the peak strength ratio condition include:

[0029] When R k =1, then the current rock sample is a weathering grade of a fresh rock sample;

[0030] When 0.8≤R k If <1.0, then the current rock sample is a slightly weathered rock sample.

[0031] When 0.4≤R k If <0.8, then the current rock sample is a moderately weathered rock sample.

[0032] When 0.2≤β<0.4, the current rock sample is a strongly weathered rock sample.

[0033] When β < 0.2, the current rock sample is a weathering grade of a completely weathered rock sample.

[0034] Optionally, according to S3, the nitrogen adsorption specific surface area test is performed on multiple rock samples to obtain the rock porosity of each rock sample, including:

[0035] S301. Select the rock sample and grind it into powder. Conduct a nitrogen adsorption specific surface area test to obtain the BET specific surface area and pore size distribution characteristics of the rock sample. Calculate the total pore volume and effective porosity of the sample by the amount of nitrogen adsorbed.

[0036] S302. Determine the pore size range, pore capacity, and proportion of different pore sizes based on pore size distribution characteristics and effective porosity.

[0037] S303. The pore size is divided into micropores, mesopores, macropores and giant pores, wherein the pore size of micropores is <2nm;

[0038] 2nm ≤ mesopore diameter < 50nm;

[0039] 50nm≤macropore diameter<100nm;

[0040] 100nm ≤ giant pore diameter;

[0041] The weathering grade classification rule for rock samples based on pore size is as follows:

[0042] The ratio of micropores to total pores in the fresh rock is K. mic ≥90%, and the proportion of mesopores K mes ≤10%, large pore ratio K mac ≤5%, the proportion of giant holes K meg ≤1%;

[0043] The ratio of micropores to total pores in the slightly weathered rock is K. mic ≥80%, and the proportion of mesoporous cells K mes ≤16%, large pore ratio K mac ≤10%, the proportion of giant holes K meg ≤2%;

[0044] The ratio of micropores to total pores in the moderately weathered rock, K mic ≥70%, and mesoporous content <16% K mes ≤25%, large pore ratio K mac ≤15%, the proportion of giant holes K meg ≤5%;

[0045] The ratio of micropores to total pores in the strongly weathered rock is K. mic ≥60%, and the proportion of large pores K mac ≥10%, mesoporous content K mes ≤30%, the proportion of giant holes K meg ≤8%;

[0046] The ratio of giant pores to total pores in the completely weathered rock, K meg ≥5%, and the proportion of micropores K mic ≤20%, mesoporous content K mes ≤15%, large pore ratio K mac ≤10%;

[0047] S304. Calculate the rock porosity K of each rock sample. The formula for calculating the rock porosity is formula (1):

[0048] K = ωmic K mic +ω mes K mes +ω mac K mac+ ω meg K meg (1)

[0049] ω mic K represents the weight of the porosity of the micropores, with a value of 0.2. mic The ratio of micropores to total pores;

[0050] ω mes K represents the weight of the mesoporous void ratio, with a value of 0.1. mes The ratio of mesopores to total pores;

[0051] ω mac K represents the weight of the porosity of macropores, with a value of 0.6. mac The ratio of macropores to total pore size;

[0052] ω meg K represents the weight of the porosity of the giant pores, with a value of 0.1. meg This represents the ratio of giant pores to all pores.

[0053] Optionally, in step S3, XRD mineral diffraction tests are performed on multiple rock samples to obtain the weathering grade of the rock samples based on the alteration mineral content conditions, including:

[0054] The rock sample was selected, ground into powder, and XRD mineral diffraction tests were conducted to determine the crystallinity of different minerals and the content of alteration minerals in the rock, wherein the content of alteration minerals A was determined. W The calculation formula is formula (2):

[0055] A W =(X Me *C Me +X Ga *C Ga +X Yi *C Yi ) / (X Me *C Me +X Ga *C Ga +X Yi *C Yi

[0056] +X qu *C qu +X fe *C fe (2)

[0057] Among them, X MeThis represents the percentage of montmorillonite content.

[0058] X Ga This represents the percentage of kaolinite content.

[0059] X Yi This represents the percentage of illite content.

[0060] X qu This represents the percentage of quartz content.

[0061] X fe This represents the percentage of feldspar content.

[0062] C Me The crystallinity of montmorillonite as obtained by XRD analysis;

[0063] C Ga The crystallinity of kaolinite as determined by XRD analysis;

[0064] C Yi The crystallinity of illite as determined by XRD analysis;

[0065] C qu The crystallinity of quartz as obtained by XRD analysis;

[0066] C fe The crystallinity of feldspar obtained by XRD analysis;

[0067] The weathering grade classification rule for rock samples based on the rock alteration mineral content conditions is as follows:

[0068] A fresh rock W Satisfy: A W ≤5%;

[0069] A of slightly weathered rocks W Satisfy: 5% < A W ≤12%;

[0070] A of moderately weathered rocks W Satisfy: 12% < A W ≤42%;

[0071] A of strongly weathered rocks W Satisfy: 42% < A W ≤88%;

[0072] A of completely weathered rock W Satisfy: 88% < A W .

[0073] Optionally, S4, based on the weathering grade of the rock sample under the longitudinal wave velocity ratio condition, the weathering grade of the rock sample under the peak strength ratio condition, the rock porosity of the rock sample, and the rock alteration mineral content of the rock sample, constructs a quantitative calculation method for the degree of rock weathering on open-pit mine slopes, resulting in a rock weathering degree grading standard including:

[0074] S401, based on parameters β, K, R k and A W A quantitative calculation formula for the weathering degree of rocks on open-pit mine slopes is obtained, and the quantitative calculation formula for the weathering degree of rocks on open-pit mine slopes is formula (3):

[0075] W=aβ+bR k +cK+dA W (3)

[0076] a represents the weight of the evaluation index for β;

[0077] b is R k The weights of the evaluation indicators;

[0078] c represents the weight of the evaluation index for K;

[0079] d is A W The weights of the evaluation indicators;

[0080] S402, The rock weathering degree grading standard includes:

[0081] When W ≤ 0.1, it is considered fresh rock.

[0082] When 0.1 < W ≤ 0.3, it is classified as slightly weathered rock.

[0083] When 0.3 < W ≤ 0.5, it is classified as moderately weathered rock.

[0084] When 0.5 < W ≤ 0.9, it is classified as strongly weathered rock.

[0085] When 0.9 < W, it is classified as a completely weathered rock.

[0086] Optionally, in step S5, based on the rock weathering degree grading standard, the mining years are used as the target time series sample to construct a spatiotemporal evolution model of the weathering degree of the open-pit mine slope, predicting future weathering time and the weathering degree of the rocks at the mining location, including:

[0087] S501. Interpolation is used to select the mining years and vertical depth to construct a bivariate nonlinear model;

[0088] S502. Based on the undetermined coefficients of the bivariate nonlinear model, the weathering degree of the rock at the future weathering time and mining location is obtained.

[0089] Optionally, the formula for the bivariate nonlinear model is formula (4):

[0090] W(t, x) = i·e jt -k·x;(4)

[0091] Where W(t, x) is the rock weathering coefficient;

[0092] t represents the number of years of mining;

[0093] i, j, and k are the fitting coefficients of the bivariate nonlinear model.

[0094] Optionally, in formula (3), the weights of the evaluation indicators follow the following rules:

[0095] When the rock sample is igneous rock, a = 0.1, b = 0.17, c = 0.32, d = 0.41;

[0096] When the rock sample is sedimentary rock, a = 0.2, b = 0.15, c = 0.12, d = 0.53;

[0097] When the rock sample is a metamorphic rock, a = 0.1, b = 0.2, c = 0.25, d = 0.45.

[0098] The above technical solution has at least the following advantages compared with the existing technology:

[0099] Compared with existing technologies, this invention comprehensively considers the macro- and micro-mechanical properties of rocks, material properties, and occurrence environment to achieve quantitative calculation and prediction of the weathering degree of rocks on open-pit mine slopes, thus providing new ideas and methods for the identification, prediction, and early warning of the weathering degree of rocks on open-pit mine slopes. Attached Figure Description

[0100] 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.

[0101] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0102] Figure 2 This is a fitted surface plot of data points on weathering time, depth of occurrence, and degree of weathering of granite in an embodiment of the present invention.

[0103] Figure 3 A fitted surface plot of weathering time, occurrence depth, and weathering degree data points of gneiss provided for the example;

[0104] Figure 4 The above are schematic diagrams of the physical adsorption isotherms of types I-VI provided in the examples. Detailed Implementation

[0105] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0106] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising,” “including,” or “including,” and similar terms mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or “connected,” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0107] It should be noted that the terms "up", "down", "left", "right", "front" and "back" used in this invention are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0108] like Figures 1 to 4 As shown, a method for predicting the weathering degree of open-pit mine slopes includes:

[0109] S1. Take on-site samples from the area to be evaluated and prepare multiple rock samples;

[0110] S2. Perform longitudinal wave velocity tests on multiple rock samples to obtain the weathering grade of the rock samples under the longitudinal wave velocity ratio condition.

[0111] Uniaxial compression tests were conducted on multiple rock samples to obtain the weathering grade of the rock samples under the peak strength ratio condition;

[0112] S3. Perform a nitrogen adsorption specific surface area test on multiple rock samples to obtain the rock porosity of each rock sample;

[0113] XRD mineral diffraction tests were performed on multiple rock samples to obtain the weathering grade of the rock samples based on the content of alteration minerals in the rock.

[0114] S4. Based on the weathering grade of the rock sample under the longitudinal wave velocity ratio condition, the weathering grade of the rock sample under the peak strength ratio condition, the rock porosity of the rock sample, and the rock alteration mineral content of the rock sample, a quantitative calculation method for the weathering degree of open-pit mine slope is constructed, and a rock weathering degree classification standard is obtained.

[0115] S5. Based on the rock weathering degree grading standard, using the mining years as the target time series sample, construct a spatiotemporal evolution model of the rock weathering degree of the open-pit mine slope to predict the future weathering time and the rock weathering degree at the mining location.

[0116] In one specific implementation, step S1 involves taking samples from the area to be evaluated in-situ and preparing multiple rock samples, including:

[0117] Weathered rocks with different mining exposure times, mining spaces, and lithologies were obtained; the weathering time gradient and vertical depth were determined according to the mining years, the selected areas were marked, and samples were prepared.

[0118] Each of the rock samples is cylindrical, with a diameter of 50 mm and a height of 100 mm. The parallelism and perpendicularity errors at both ends of the rock sample are less than or equal to 0.03 mm.

[0119] In this step, the mining progress of the mining slope in the area to be evaluated is investigated, the mining plan is reviewed, and weathered rocks with different mining exposure times, mining spaces, and different lithologies are obtained. The weathering time gradient and vertical depth are determined according to the mining years, the selected area is marked, and samples are prepared. The prepared samples are cylindrical specimens with a diameter of 50 mm and a height of 100 mm. The parallelism and perpendicularity errors at both ends of the specimen must not exceed 0.03 mm, and the preparation must strictly follow the methods recommended by the International Society for Rock Mechanics. Notably, joint and fracture surfaces do not need to be deliberately avoided during sample preparation; the bedding structure of the original rock sample should be preserved.

[0120] In one specific implementation, the weathering grade of the rock sample under the longitudinal wave velocity ratio condition in S2 includes:

[0121] S201. Measure the length and diameter of the rock sample with a graduated ruler, accurate to the millimeter level. That is, measure the length of the rock specimen with a graduated ruler (accurate to the millimeter). Apply coupling agent evenly to both ends. When the wave velocity tester emits a uniform and stable sound wave, start the test. Take multiple measurements for each group of samples and take the average value.

[0122] S202. Coupling agent is evenly applied to both ends of the multiple rock samples. After the wave velocity tester emits sound waves evenly and stably, the test is started. Based on the longitudinal wave velocity of each rock sample, the longitudinal wave velocity ratio β of the rock sample and the fresh rock is calculated to obtain the weathering grade of the rock sample under the longitudinal wave velocity ratio condition.

[0123] The weathering grade classification rules for rock samples under the longitudinal wave velocity ratio condition include:

[0124] When 0.9≤β≤1.0, the current rock sample is the weathering grade of a fresh rock sample;

[0125] When 0.8 ≤ β < 0.9, the current rock sample is a slightly weathered rock sample.

[0126] When 0.6≤β<0.8, the current rock sample is a moderately weathered rock sample.

[0127] When 0.4≤β<0.6, the current rock sample is a strongly weathered rock sample.

[0128] When β < 0.4, the current rock sample is a weathering grade of a completely weathered rock sample.

[0129] In one specific implementation, the weathering grade of the rock samples obtained by performing uniaxial compression tests on multiple rock samples in step S2, under the condition of peak strength ratio, includes:

[0130] S211. Perform uniaxial compression tests on multiple rock samples respectively to obtain the peak strength of each rock sample;

[0131] S212. Calculate the peak strength ratio R of each rock sample to that of fresh rock. k The weathering grade of the rock sample under the peak strength ratio condition was obtained;

[0132] The weathering grade classification rules for rock samples under the peak strength ratio condition include:

[0133] When R k =1, then the current rock sample is a weathering grade of a fresh rock sample;

[0134] When 0.8≤R k If <1.0, then the current rock sample is a slightly weathered rock sample.

[0135] When 0.4≤R k If <0.8, then the current rock sample is a moderately weathered rock sample.

[0136] When 0.2≤β<0.4, the current rock sample is a strongly weathered rock sample.

[0137] When β < 0.2, the current rock sample is a weathering grade of a completely weathered rock sample.

[0138] In one specific implementation, according to step S3, a nitrogen adsorption specific surface area test is performed on multiple rock samples to obtain the rock porosity of each rock sample, including:

[0139] S301. Select the rock sample, grind it into powder, and conduct a nitrogen adsorption specific surface area test to obtain the BET specific surface area and pore size distribution characteristics of the rock sample. Calculate the total pore volume and effective porosity of the sample based on the amount of nitrogen adsorbed.

[0140] In fact, by conducting nitrogen adsorption specific surface area tests, the specific surface area inside the micropores by t-plot method, the specific surface area outside the micropores by t-plot method, the total pore volume / pore volume by single-point method (the ratio of pore volume / pore volume calculated by single-point method), the micropore volume / pore volume by t-plot method (the ratio of micropore volume / pore volume calculated by t-plot method), the average pore diameter, and the mesopore diameter of the corresponding rock sample can be obtained. By plotting the isothermal adsorption-desorption curves and adsorption capacity curves under relative pressure, the total pore volume and effective porosity of the sample can be estimated.

[0141] S302. The pore size range, pore capacity, and proportion of different pore sizes are determined based on pore size distribution characteristics and effective porosity. Specifically, the pore size distribution characteristics within weathered rocks are determined primarily by comparing adsorption curve characteristics and hysteresis loop morphology with type I-VI adsorption isotherms. The pore size range, pore capacity, and proportion of different pore sizes are then determined based on these pore size distribution characteristics. The type I-VI adsorption isotherms can be found in [reference needed]. Figure 4 ;

[0142] S303. The pore size is divided into micropores, mesopores, macropores and giant pores, wherein the micropore diameter is <2nm; 2nm≤mesopore diameter<50nm; 50nm≤macropore diameter<100nm; and 100nm≤giant pore diameter.

[0143] The weathering grade classification rule for rock samples based on pore size is as follows:

[0144] The ratio of micropores to total pores in the fresh rock is K. mic ≥90%, and the proportion of mesopores K mes ≤10%, large pore ratio K mac ≤5%, the proportion of giant holes K meg ≤1%;

[0145] The ratio of micropores to total pores in the slightly weathered rock is K. mic ≥80%, and the proportion of mesoporous cells Kmes ≤16%, large pore ratio K mac ≤10%, the proportion of giant holes K meg ≤2%;

[0146] The ratio of micropores to total pores in the moderately weathered rock, K mic ≥70%, and mesoporous content <16% K mes ≤25%, large pore ratio K mac ≤15%, the proportion of giant holes K meg ≤5%;

[0147] The ratio of micropores to total pores in the strongly weathered rock is K. mic ≥60%, and the proportion of large pores K mac ≥10%, mesoporous content K mes ≤30%, the proportion of giant holes K meg ≤8%;

[0148] The ratio of giant pores to total pores in the completely weathered rock, K meg ≥5%, and the proportion of micropores K mic ≤20%, mesoporous content K mes ≤15%, large pore ratio K mac ≤10%;

[0149] S304. Calculate the rock porosity K of each rock sample. The formula for calculating the rock porosity is formula (1):

[0150] K = ω mic K mic +ω mes K mes +ω mac K mac+ ω meg K meg (1)

[0151] ω mic K represents the weight of the porosity of the micropores, with a value of 0.2. mic The ratio of micropores to total pores;

[0152] ω mes K represents the weight of the mesoporous void ratio, with a value of 0.1. mes The ratio of mesopores to total pores;

[0153] ω mac K represents the weight of the porosity of macropores, with a value of 0.6. mac The ratio of macropores to total pore size;

[0154] ω meg K represents the weight of the porosity of the giant pores, with a value of 0.1. megThe ratio of giant pores to total pore size;

[0155] The weights for the aforementioned parameters are as follows: micropores generally have a significant impact on the permeability, water storage capacity, and gas / liquid adsorption of rocks; mesopores affect the intermediate properties of rocks such as air permeability, permeability, and liquid storage capacity; macropores play an important role in the physical strength, structural stability, and rapid liquid permeation of rocks; and giant pores have a significant impact on the gas and water storage capacity of rocks. Based on the influence of different pore sizes on the mechanical properties of weathered rocks, the weights are assigned as follows: micropores are assigned a weight of 0.2, mesopores 0.1, macropores 0.6, and giant pores 0.1.

[0156] In one specific implementation, step S3 involves performing XRD mineral diffraction tests on multiple rock samples to obtain the weathering grade of the rock samples based on the alteration mineral content conditions, including:

[0157] The rock sample was selected, ground into powder, and XRD mineral diffraction tests were conducted to determine the crystallinity of different minerals and the content of alteration minerals in the rock, wherein the content of alteration minerals A was determined. W The calculation formula is formula (2):

[0158] A W =(X Me *C Me +X Ga *C Ga +X Yi *C Yi ) / (X Me *C Me +X Ga *C Ga +X Yi *C Yi

[0159] +X qu *C qu +X fe *C fe (2)

[0160] Among them, X Me This represents the percentage of montmorillonite content.

[0161] X Ga This represents the percentage of kaolinite content.

[0162] X Yi This represents the percentage of illite content.

[0163] X qu This represents the percentage of quartz content.

[0164] X fe This represents the percentage of feldspar content.

[0165] C Me The crystallinity of montmorillonite as obtained by XRD analysis;

[0166] C Ga The crystallinity of kaolinite as determined by XRD analysis;

[0167] C Yi The crystallinity of illite as determined by XRD analysis;

[0168] C qu The crystallinity of quartz as obtained by XRD analysis;

[0169] C fe The crystallinity of feldspar obtained by XRD analysis;

[0170] The weathering grade classification rule for rock samples based on the rock alteration mineral content conditions is as follows:

[0171] A fresh rock W Satisfy: A W ≤5%;

[0172] A of slightly weathered rocks W Satisfy: 5% < A W ≤12%;

[0173] A of moderately weathered rocks W Satisfy: 12% < A W ≤42%;

[0174] A of strongly weathered rocks W Satisfy: 42% < A W ≤88%;

[0175] A of completely weathered rock W Satisfy: 88% < A W .

[0176] In one specific implementation, step S4, based on the weathering grade of the rock sample under the longitudinal wave velocity ratio condition, the weathering grade of the rock sample under the peak intensity ratio condition, the rock porosity of the rock sample, and the rock alteration mineral content of the rock sample, constructs a quantitative calculation method for the degree of rock weathering on open-pit mine slopes, resulting in a rock weathering degree grading standard including:

[0177] S401, based on parameters β, K, R k and A W A quantitative calculation formula for the weathering degree of rocks on open-pit mine slopes is obtained, and the quantitative calculation formula for the weathering degree of rocks on open-pit mine slopes is formula (3):

[0178] W=aβ+bR k+cK+dA W (3)

[0179] a represents the weight of the evaluation index for β;

[0180] b is R k The weights of the evaluation indicators;

[0181] c represents the weight of the evaluation index for K;

[0182] d is A W The weights of the evaluation indicators;

[0183] When the rock sample is igneous rock, a = 0.1, b = 0.17, c = 0.32, and d = 0.41.

[0184] When the rock sample is sedimentary rock, a = 0.2, b = 0.15, c = 0.12, d = 0.53;

[0185] When the rock sample is metamorphic rock, a = 0.1, b = 0.2, c = 0.25, d = 0.45;

[0186] S402, The rock weathering degree grading standard includes:

[0187] When W ≤ 0.1, it is considered fresh rock.

[0188] When 0.1 < W ≤ 0.3, it is classified as slightly weathered rock.

[0189] When 0.3 < W ≤ 0.5, it is classified as moderately weathered rock.

[0190] When 0.5 < W ≤ 0.9, it is classified as strongly weathered rock.

[0191] When 0.9 < W, it is classified as a completely weathered rock.

[0192] Optionally, in step S5, based on the rock weathering degree grading standard, the mining years are used as the target time series sample to construct a spatiotemporal evolution model of the weathering degree of the open-pit mine slope, predicting future weathering time and the weathering degree of the rocks at the mining location, including:

[0193] S501. Interpolation is used to select the mining years and vertical depth to construct a bivariate nonlinear model;

[0194] S502. Based on the undetermined coefficients of the bivariate nonlinear model, the weathering degree of the rock at the future weathering time and mining location is obtained.

[0195] In one specific implementation, the formula for the bivariate nonlinear model is formula (4):

[0196] W(t, x) = i·ejt -k·x;(4)

[0197] Where W(t, x) is the rock weathering coefficient;

[0198] t represents the number of years of mining;

[0199] i, j, and k are the fitting coefficients of the bivariate nonlinear model, respectively.

[0200] Example 1: Taking granite as an example, the weathering degree W of the open-pit mine slope is calculated. Based on this, the weathering degree level of the rock in the area to be evaluated is determined, and the weathering degree of the rock in the subsequent mining years is predicted. The specific implementation process is as follows:

[0201] In the area to be evaluated, the weathering period of mining was determined. Weathered granite rocks from different mining exposure times and spaces were selected, and standard cylindrical specimens with a diameter of 50 mm and a height of 100 mm were prepared. The parallelism and perpendicularity errors at both ends of the specimens should not exceed 0.03 mm, and the preparation should be strictly in accordance with the methods recommended by the International Society for Rock Mechanics. In particular, it is not necessary to deliberately expose the jointed and fractured parts of the original rock specimens during specimen preparation; the original bedding structure should be preserved.

[0202] For the prepared rock samples, P-wave velocity tests were conducted at different sampling locations to obtain the P-wave velocity ratio between weathered and fresh rocks. A total of six sampling locations were used, with each sampling point spaced 10 years apart from the mining time: 10, 20, 30, 40, 50, and 60 years. The average P-wave velocities of the weathered rocks were 5.24 km / s, 5.07 km / s, 5 km / s, 4.63 km / s, 4.2 km / s, and 4.18 km / s, respectively, while the P-wave velocity of the fresh rocks was 6.1 km / s. The calculated P-wave velocity ratios β were 0.859, 0.831, 0.81, 0.759, 0.689, and 0.685, respectively.

[0203] A series of uniaxial compression tests were conducted to obtain the uniaxial compressive strength of weathered rock. The average value of multiple tests was taken. The uniaxial compressive strengths of the weathered rock were 79.41 MPa, 67.43 MPa, 58.84 MPa, 52.27 MPa, 47.9 MPa, and 31.67 MPa, respectively. The uniaxial compressive strength of fresh rock was 83.83 MPa. The uniaxial compressive strength ratio R was calculated. h The values ​​are 0.947, 0.804, 0.701, 0.623, 0.571, and 0.377, respectively.

[0204] Nitrogen adsorption specific surface area (BET) tests were conducted to determine the proportion of pores of different sizes in rocks with different weathering degrees at a microscopic angle. The calculated pore size ratios (K) were 0.1997, 0.1901, 0.1892, 0.1887, 0.1885, and 0.1792. The calculation formulas and test results for samples with different weathering degrees are shown in Table-1 below. Table-1 references the following formulas:

[0205] K = 0.2K mic +0.1K mex +0.6K mac +0.1K meg .

[0206] Table 1

[0207] Mining life (years) <![CDATA[Micropore ratio K mic > <![CDATA[Mesopore proportion K mes > <![CDATA[Large pore proportion K mac > <![CDATA[Macropore proportion K meg > 10 0.917 0.037 0.021 0 20 0.861 0.077 0.017 0 30 0.815 0.082 0.028 0.015 40 0.732 0.147 0.042 0.029 50 0.615 0.207 0.054 0.124 60 0.607 0.184 0.037 0.172

[0208] The rock sample was ground into powder and XRD mineral diffraction was performed to determine the mineral composition and content changes between fresh and weathered rocks. The crystallinity of each component obtained from the XRD mineral diffraction is shown in Table 2 below. The alteration mineral content A of the rock was calculated. W The percentages were 8.38%, 12.24%, 22.37%, 31.83%, 45.67%, and 59.17%, respectively.

[0209] Table 2

[0210]

[0211] According to the aforementioned quantitative evaluation indicators of weathering, they are macroscopic parameters (longitudinal wave velocity ratio β, peak intensity ratio R). A ) and microscopic parameters (rock porosity K, alteration mineral content A) W According to the quantitative calculation formula for the weathering degree of rocks on open-pit mine slopes, granite is an igneous rock, and the calculated weathering degrees are 0.345, 0.350, 0.352, 0.373, 0.414, and 0.433, respectively. The weathering degree is moderately weathered rock mass, and the formula is as follows:

[0212] W = 0.1β + 0.17R A +0.32K+0.41A W ;

[0213] By selecting different mining years and vertical depths for interpolation, and substituting them into the equation, the spatiotemporal evolution equation of weathered rocks is obtained as follows:

[0214] W(t, x) = 0.3445·e 0.024t +0.0000676·x;

[0215] Based on this equation, the weathering grade of rocks after weathering over a longer period of time can be further deduced. See [link to relevant documentation]. Figure 2 ,exist Figure 2 In this paper, 0 meters represents the horizontal plane. This invention targets weathered rocks on open-pit mine slopes. Open-pit mining begins above the horizontal plane, hence the value is positive. From top to bottom, the lower the depth until the depth becomes negative, the lower the degree of weathering. Existing sampling data and the weathering degree levels of open-pit mine slope rocks are shown in Table 3.

[0216] Table 3

[0217] Mining life (years) Rock weathering degree W Weathering level 10 0.345 Stroke 20 0.35 Stroke 30 0.352 Stroke 40 0.373 Stroke 50 0.414 Stroke 60 0.433 Stroke

[0218] Example 2:

[0219] Taking gneiss as an example, the weathering degree W of the open-pit mine slope is calculated, and the weathering degree level of the rock in the area to be evaluated is determined accordingly. The weathering degree of the rock is also predicted for the subsequent mining years. The specific implementation process is as follows:

[0220] In the area to be evaluated, the weathering period of mining was clarified. Gneiss weathered rocks with different mining exposure times and mining spaces were selected, and standard cylindrical specimens with a diameter of 50 mm and a height of 100 mm were prepared. The parallelism error and perpendicularity error at both ends of the specimen should not exceed 0.03 mm, and the preparation should be carried out strictly in accordance with the methods recommended by the International Society for Rock Mechanics. In particular, when preparing the specimens, it is not necessary to deliberately expose the jointed and fractured parts of the original rock specimens; the original bedding structure should be preserved.

[0221] For the prepared rock samples, P-wave velocity tests were conducted at different sampling locations to obtain the P-wave velocity ratio between weathered and fresh rocks. A total of six sampling locations were used, with each sampling point spaced 10 years apart from the mining time: 5 years, 15 years, 25 years, 35 years, 45 years, and 55 years. The average P-wave velocities of the weathered rocks from multiple experiments were 6.28 km / s, 6.0 km / s, 5.73 km / s, 5.51 km / s, 5.38 km / s, and 4.77 km / s, respectively, while the P-wave velocity of the fresh rocks was 6.84 km / s. The calculated P-wave velocity ratios β were 0.918, 0.877, 0.838, 0.806, 0.787, and 0.697, respectively.

[0222] A series of uniaxial compression tests were conducted to obtain the uniaxial compressive strength of weathered rock. The average value of multiple experiments was taken. The uniaxial compressive strengths of the weathered rock were 105.80 MPa, 96.56 MPa, 73.87 MPa, 52.67 MPa, 42.47 MPa, and 36.19 MPa, respectively. The uniaxial compressive strength of fresh rock was 112.47 MPa. The uniaxial compressive strength ratio R was calculated. AThe values ​​were 0.941, 0.859, 0.657, 0.468, 0.378, and 0.322, respectively. Nitrogen adsorption specific surface area (BET) tests were conducted to determine the proportion of pores of different sizes in rocks with different weathering degrees at a microscopic angle. The calculated values ​​of the rock porosity K were 0.208, 0.213, 0.238, 0.206, 0.206, and 0.189, respectively. The calculation formulas and the proportions of different pore sizes are shown in Table-4 below.

[0223] K = 0.2K mic +0.1K mex +0.6K mac +0.1K mec ;

[0224] Table 4

[0225] Mining life (years) <![CDATA[Microvoid ratio K mic > <![CDATA[Mesopore proportion K mes > <![CDATA[Macropore proportion K mac > <![CDATA[Macropore proportion K meg > 5 0.942 0.018 0.027 0.013 15 0.871 0.047 0.051 0.031 25 0.827 0.035 0.111 0.028 35 0.742 0.104 0.063 0.091 45 0.651 0.192 0.082 0.075 55 0.597 0.158 0.058 0.187

[0226] The rock sample was ground into powder and XRD mineral diffraction was performed to determine the mineral composition and content changes between fresh and weathered rocks. The crystallinity of each component obtained from the XRD mineral diffraction is shown in Table 5 below. The alteration mineral content A of the rock was calculated. W The percentages were 6.54%, 11.83%, 19.64%, 28.47%, 37.62%, and 51.08%, respectively.

[0227] Table 5

[0228]

[0229] According to the aforementioned quantitative evaluation indicators of weathering, they are macroscopic parameters (longitudinal wave velocity ratio β, peak intensity ratio R). A ) and microscopic parameters (rock porosity K, alteration mineral content A) W Based on the quantitative calculation formula for the weathering degree of rocks on open-pit mine slopes, the calculated weathering degrees are 0.354, 0.361, 0.363, 0.366, 0.375, and 0.411, respectively. The weathering degree is classified as moderately weathered rock. The calculation formula is as follows:

[0230] W = 0.1β + 02R A +0.25K +0.45A W ;

[0231] By selecting different mining years and vertical depths for interpolation, and substituting them into the equation, the spatiotemporal evolution equation of weathered rocks is obtained as follows:

[0232] W(t, x) = 0.396·e 0.009 -0.00039·x;

[0233] Based on this equation, the weathering grade of rocks after weathering over a longer period of time can be further deduced. See [link to relevant documentation]. Figure 3 The existing sampling data and the weathering degree of rocks on the open-pit mine slope are shown in Table 6.

[0234] Table 6

[0235] Mining life (years) Rock weathering degree W Weathering level 5 0.354 Stroke 15 0.361 Stroke 25 0.363 Stroke 35 0.366 Stroke 45 0.375 Stroke 55 0.411 Stroke

[0236] In summary, this embodiment establishes a quantitative evaluation and prediction method for rock weathering degree that comprehensively considers the size and number of internal pores, alteration mineral content, peak rock strength, and P-wave velocity ratio. Traditional rock weathering degree assessment remains qualitative, often relying on engineering geological evaluations of open-pit mine slope weathering, primarily based on rock mass structure, rock color, and mineral composition. This approach is highly subjective, leading to inaccurate assessments of weathering degree and an inability to predict future weathering trends. Therefore, this method combines macro- and micro-level quantitative analysis of rock weathering degree. Macro-level parameters include rock wave velocity ratio and uniaxial compressive strength, while micro-level parameters include the porosity of different open pores and alteration mineral content. This method comprehensively considers the rock's mechanical properties and its weathering environment, enabling quantitative evaluation of open-pit mine slope weathering degree. Furthermore, it uses a spatiotemporal evolution model of weathered rock mining fitted with the depth of occurrence and mining time to further predict the degree of weathering, allowing for timely support and reinforcement in engineering to prevent further disasters.

[0237] The following points need to be explained:

[0238] (1) The accompanying drawings of the embodiments of the present invention only involve the structures involved in the embodiments of the present invention. Other structures can refer to the general design.

[0239] (2) For clarity, the thickness of layers or regions is enlarged or reduced in the drawings used to describe embodiments of the present invention; that is, these drawings are not drawn to actual scale. It is understood that when an element such as a layer, film, region, or substrate is referred to as being “above” or “below” another element, the element may be “directly” located “above” or “below” the other element, or there may be intermediate elements.

[0240] (3) Where there is no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

[0241] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for predicting the weathering degree of open-pit mine slopes, characterized in that, include: S1. Take on-site samples from the area to be evaluated and prepare multiple rock samples; S2. Perform longitudinal wave velocity tests on multiple rock samples to obtain the weathering grade of the rock samples under the longitudinal wave velocity ratio condition. Uniaxial compression tests were conducted on multiple rock samples to obtain the weathering grade of the rock samples under the peak strength ratio condition; S3. Perform a nitrogen adsorption specific surface area test on multiple rock samples to obtain the rock porosity of each rock sample; XRD mineral diffraction tests were performed on multiple rock samples to obtain the weathering grade of the rock samples based on the content of alteration minerals in the rock. S4. Based on the weathering grade of the rock sample under the longitudinal wave velocity ratio condition, the weathering grade of the rock sample under the peak strength ratio condition, the rock porosity of the rock sample, and the rock alteration mineral content of the rock sample, a quantitative calculation method for the weathering degree of open-pit mine slope is constructed, and a rock weathering degree classification standard is obtained. S5. Based on the rock weathering degree grading standard, using the mining years as the target time series sample, construct a spatiotemporal evolution model of the rock weathering degree of the open-pit mine slope to predict the future weathering time and the rock weathering degree at the mining location.

2. The method for predicting the weathering degree of open-pit mine slopes according to claim 1, characterized in that, S1 involves on-site sampling of the area to be evaluated and preparation of multiple rock samples, including: Weathered rocks with different mining exposure times, mining spaces, and lithologies were obtained; the weathering time gradient and vertical depth were determined according to the mining years, the selected areas were marked, and samples were prepared. Each of the rock samples is cylindrical, with a diameter of 50 mm and a height of 100 mm. The parallelism and perpendicularity errors at both ends of the rock sample are less than or equal to 0.03 mm.

3. The method for predicting the weathering degree of open-pit mine slopes according to claim 2, characterized in that, The weathering grades of the rock samples under the P-wave velocity ratio condition in S2 include: S201. Measure the length and diameter of the rock sample with a graduated ruler, accurate to the millimeter level; S202. Coupling agent is evenly applied to both ends of the multiple rock samples. After the wave velocity tester emits sound waves evenly and stably, the test is started. Based on the longitudinal wave velocity of each rock sample, the longitudinal wave velocity ratio β of the rock sample and the fresh rock is calculated to obtain the weathering grade of the rock sample under the longitudinal wave velocity ratio condition. The weathering grade classification rules for rock samples under the longitudinal wave velocity ratio condition include: When 0.9≤β≤1.0, the current rock sample is the weathering grade of a fresh rock sample; When 0.8 ≤ β < 0.9, the current rock sample is a slightly weathered rock sample. When 0.6≤β<0.8, the current rock sample is a moderately weathered rock sample. When 0.4≤β<0.6, the current rock sample is a strongly weathered rock sample. When β < 0.4, the current rock sample is a weathering grade of a completely weathered rock sample.

4. The method for predicting the weathering degree of open-pit mine slopes according to claim 3, characterized in that, The weathering grade of the rock samples obtained by performing uniaxial compression tests on multiple rock samples in step S2, under the condition of peak strength ratio, includes: S211. Perform uniaxial compression tests on multiple rock samples respectively to obtain the peak strength of each rock sample; S212. Calculate the peak strength ratio R of each rock sample to that of fresh rock. k The weathering grade of the rock sample under the peak strength ratio condition was obtained; The weathering grade classification rules for rock samples under the peak strength ratio condition include: When R k =1, then the current rock sample is a weathering grade of a fresh rock sample; When 0.8≤R k If <1.0, then the current rock sample is a slightly weathered rock sample. When 0.4≤R k If <0.8, then the current rock sample is a moderately weathered rock sample. When 0.2≤β<0.4, the current rock sample is a strongly weathered rock sample. When β < 0.2, the current rock sample is a weathering grade of a completely weathered rock sample.

5. The method for predicting the weathering degree of open-pit mine slopes according to claim 4, characterized in that, Based on the nitrogen adsorption specific surface area test conducted on multiple rock samples in step S3, the rock porosity of each rock sample is obtained as follows: S301. Select the rock sample and grind it into powder. Conduct a nitrogen adsorption specific surface area test to obtain the BET specific surface area and pore size distribution characteristics of the rock sample. Calculate the total pore volume and effective porosity of the sample by the amount of nitrogen adsorbed. S302. Determine the pore size range, pore capacity, and proportion of different pore sizes based on pore size distribution characteristics and effective porosity. S303. The pore size is divided into micropores, mesopores, macropores and giant pores, wherein the pore size of micropores is <2nm; 2nm ≤ mesopore size < 50nm; 50nm≤macropore diameter<100nm; 100nm ≤ giant pore diameter; The weathering grade classification rule for rock samples based on pore size is as follows: The ratio of micropores to total pores in the fresh rock is K. mic ≥90%, and the proportion of mesopores K mes ≤10%, large pore ratio K mac ≤5%, the proportion of giant holes K meg ≤1%; The ratio of micropores to total pores in the slightly weathered rock is K. mic ≥80%, and the proportion of mesoporous cells K mes ≤16%, large pore ratio K mac ≤10%, the proportion of giant holes K meg ≤2%; The ratio of micropores to total pores in the moderately weathered rock, K mic ≥70%, and mesoporous content <16% K mes ≤25%, large pore ratio K mac ≤15%, the proportion of giant holes K meg ≤5%; The ratio of micropores to total pores in the strongly weathered rock is K. mic ≥60%, and the proportion of large pores K mac ≥10%, mesoporous content K mes ≤30%, the proportion of giant holes K meg ≤8%; The ratio of giant pores to total pores in the completely weathered rock, K meg ≥5%, and the proportion of micropores K mic ≤20%, mesoporous content K mes ≤15%, large pore ratio K mac ≤10%; S304. Calculate the rock porosity K of each rock sample. The formula for calculating the rock porosity is formula (1): K=ω mic K mic +oh mes K mes +oh mac K mac+ oh meg K meg ;(1) ω mic K represents the weight of the porosity of the micropores, with a value of 0.

2. mic The ratio of micropores to total pores; ω mes K represents the weight of the mesoporous void ratio, with a value of 0.

1. mes The ratio of mesopores to total pores; ω mac K represents the weight of the porosity of macropores, with a value of 0.

6. mac The ratio of macropores to total pore size; ω meg K represents the weight of the porosity of the giant pores, with a value of 0.

1. meg This represents the ratio of giant pores to all pores.

6. The method for predicting the weathering degree of open-pit mine slopes according to claim 5, characterized in that, In step S3, XRD mineral diffraction tests are performed on multiple rock samples to obtain the weathering grade of the rock samples based on the alteration mineral content conditions, including: The rock sample was selected, ground into powder, and XRD mineral diffraction tests were conducted to determine the crystallinity of different minerals and the content of alteration minerals in the rock, wherein the content of alteration minerals A was determined. W The calculation formula is formula (2): A W =(X Me *C Me +X Ga *C Ga +X Yi *C Yi ) / (X Me *C Me +X Ga *C Ga +X Yi *C Yi +X qu *C qu +X fe *C fe );(2) Among them, X Me This represents the percentage of montmorillonite content. X Ga This represents the percentage of kaolinite content. X Yi This represents the percentage of illite content. X qu This represents the percentage of quartz content. X fe This represents the percentage of feldspar content. C Me The crystallinity of montmorillonite as obtained by XRD analysis; C Ga The crystallinity of kaolinite as determined by XRD analysis; C Yi The crystallinity of illite as determined by XRD analysis; C qu The crystallinity of quartz as obtained by XRD analysis; C fe The crystallinity of feldspar obtained by XRD analysis; The weathering grade classification rule for rock samples based on the rock alteration mineral content conditions is as follows: A fresh rock W Satisfy: A W ≤5%; A of slightly weathered rocks W Satisfy: 5% < A W ≤12%; A of moderately weathered rocks W Satisfy: 12% < A W ≤42%; A of strongly weathered rocks W Satisfy: 42% < A W ≤88%; A of completely weathered rock W Satisfy: 88% < A W .

7. The method for predicting the weathering degree of open-pit mine slopes according to claim 6, characterized in that, The method described in S4, based on the weathering grade of the rock sample under the longitudinal wave velocity ratio condition, the weathering grade of the rock sample under the peak strength ratio condition, the rock porosity of the rock sample, and the rock alteration mineral content of the rock sample, constructs a quantitative calculation method for the degree of rock weathering on open-pit mine slopes, resulting in a rock weathering degree grading standard including: S401, based on parameters β, K, R k and A W A quantitative calculation formula for the weathering degree of rocks on open-pit mine slopes is obtained, and the quantitative calculation formula for the weathering degree W of rocks on open-pit mine slopes is formula (3): W=aβ+bR k +cK+dA W ;(3) a represents the weight of the evaluation index for β; b is R k The weights of the evaluation indicators; c represents the weight of the evaluation index for K; d is A W The weights of the evaluation indicators; S402, The rock weathering degree grading standard includes: When W ≤ 0.1, it is considered fresh rock. When 0.1 < W ≤ 0.3, it is classified as slightly weathered rock. When 0.3 < W ≤ 0.5, it is classified as moderately weathered rock. When 0.5 < W ≤ 0.9, it is classified as strongly weathered rock. When 0.9 < W, it is classified as a completely weathered rock.

8. The method for predicting the weathering degree of open-pit mine slopes according to claim 7, characterized in that, S5, based on the rock weathering degree grading standard, uses the mining years as the target time series sample to construct a spatiotemporal evolution model of the rock weathering degree on the open-pit mine slope, predicting future weathering time and the rock weathering degree at the mining location, including: S501. Interpolation is used to select the mining years and vertical depth to construct a bivariate nonlinear model; S502. Based on the undetermined coefficients of the bivariate nonlinear model, the weathering degree of the rock at the future weathering time and mining location is obtained.

9. The method for predicting the weathering degree of open-pit mine slopes according to claim 8, characterized in that, The formula for the bivariate nonlinear model is formula (4): W(t,x)=i·e jt -k·x;(4) Where W(t, x) is the rock weathering coefficient; t represents the number of years of mining; i, j, and k are the fitting coefficients of the bivariate nonlinear model, respectively.

10. The method for predicting the weathering degree of open-pit mine slopes according to claim 7, characterized in that, In formula (3), the weights of the evaluation indicators follow the following rules: When the rock sample is igneous rock, a=0.1, b=0.17, c=0.32, d=0.41; When the rock sample is sedimentary rock, a=0.2, b=0.15, c=0.12, d=0.53; When the rock sample is a metamorphic rock, a=0.1, b=0.2, c=0.25, d=0.45.

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