Prediction method and system for uniaxial compression porosity ratio of rockfill aggregate considering the influence of wet-dry cycles

Abstract

The present invention provides a prediction method and system for the uniaxial compression void ratio of rockfill aggregates considering the influence of wet-dry cycles, including: screening out multiple groups of rockfill aggregates that conform to the particle size distribution characteristics of rockfill; conducting wet-dry cycle tests under different established numbers of wet-dry cycles N; conducting uniaxial compression tests; constructing a prediction model for the uniaxial compression void ratio e of rockfill aggregates considering the influence of the number of wet-dry cycles N; and predicting the uniaxial compression void ratio e of rockfill aggregates that conform to the same particle size distribution characteristics of rockfill aggregates after experiencing different numbers of wet-dry cycles N under different axial stresses σ v . The present invention fully considers the influence of wet-dry cycles caused by the rise and fall of the reservoir water level on the deformation of rockfill, obtains data that is more consistent with the actual void ratio of rockfill, and provides a scientific and effective means for predicting the deformation of actual rockfill dams during operation under the influence of cyclic changes in the reservoir water level.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical engineering material test research, and in particular relates to a method and a system for predicting the uniaxial compression porosity ratio of a rockfill material assembly taking into account the influence of dry-wet cycles. Background Art

[0002] With the continuous development of advanced design theories and dam-building technologies, rockfill dam design and construction technologies are becoming more and more perfect. For example, intelligent construction technologies represented by unmanned intelligent rolling and integrated air-space-ground safety monitoring technologies have significantly promoted the technological progress of the industry.

[0003] However, some existing projects have experienced problems such as longitudinal cracks on the dam crest caused by uncoordinated dam deformation, such as core rockfill dams such as Pubugou, Xiaolangdi, and Maoergai. Existing analysis has shown that during normal operation, core rockfill dams such as Pubugou and Xiaolangdi projects experience frequent fluctuations in reservoir water levels due to factors such as rainfall, runoff, evaporation, water use, and underground seepage, which causes the rockfill materials in the water level fluctuation area to deteriorate and reduce their strength, making them more easily broken under high stress, which in turn causes uneven deformation of the upstream and downstream dam bodies of the core rockfill dam, leading to problems such as longitudinal cracks on the dam crest.

[0004] Therefore, accurately understanding the degradation law of the physical and mechanical properties of rockfill materials under the influence of relevant factors in the actual operating environment of rockfill dams can provide a reference for predicting the deformation of actual rockfill dam projects under the influence of relevant factors during operation. This is the key to ensuring the safe operation of rockfill dams throughout their life cycle and is of great significance to ensuring the safe operation of rockfill dams and the safety of life and property of the people downstream. Summary of the invention

[0005] In view of the defects in the prior art, the present invention provides a method and system for predicting the uniaxial compression porosity of rockfill aggregates taking into account the influence of dry-wet cycles, which can effectively solve the above problems.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The present invention provides a method for predicting the uniaxial compression porosity of a rockfill material assembly taking into account the influence of dry-wet cycles, comprising the following steps:

[0008] Step S1, screening the rockfill material particles to select multiple groups of rockfill material assemblies that meet the particle size distribution characteristics of the rockfill material particles;

[0009] Step S2: performing different predetermined dry-wet cycles on each group of rockfill material assemblies. Dry-wet cycle test under 200℃;

[0010] Step S3, complete a predetermined number of dry-wet cycles for each group The rockfill aggregate of the dry-wet cycle test is subjected to a uniaxial compression test to obtain a predetermined number of dry-wet cycles. The corresponding axial stress With axial strain The uniaxial compression curve of each group is analyzed to determine the number of dry-wet cycles each group undergoes. The yield stress of the rockfill aggregate after ;

[0011] Step S4, each group undergoes a predetermined number of dry-wet cycles according to the number of dry-wet cycles obtained in step S3 The yield stress of the rockfill aggregate after , the construction is obtained by considering the number of dry-wet cycles Uniaxial compression porosity ratio of rockfill aggregates prediction models;

[0012] Step S5, using the uniaxial compression porosity ratio of the rockfill aggregate The prediction model is used to predict the rockfill aggregate with the same particle size distribution characteristics after experiencing different drying and wetting cycles. After that, at different axial stress The uniaxial compression porosity ratio Make predictions.

[0013] Preferably, in step S1, the particle size distribution characteristics of the rockfill material particles are in accordance with formula (1):

[0014] (1)

[0015] Where: d is the particle size of the rockfill material within the set particle size range; is the gamma function; P0, , d c and m are the first model parameter, the second model parameter, the third model parameter, the fourth model parameter and the fifth model parameter of formula (1), respectively; P is the mass percentage of the corresponding rockfill material particle size d in the rockfill material aggregate.

[0016] Preferably, the particle size range is set to 5-15 mm; the first model parameter P0 and the second model parameter , the third model parameter , the fourth model parameter d c and the fifth model parameter m, are set to -13.9, 1292, 10, 14, and 170, respectively.

[0017] Preferably, the screened rockfill material particles are divided into 4 to 5 groups of rockfill material assemblies.

[0018] Preferably, the particle size distribution characteristics of the rockfill are as follows: the mass percentage of small-sized rockfill with a particle size of 5-7 mm is 20%; the mass percentage of medium-sized rockfill with a particle size of 7-12 mm is 70%; the mass percentage of large-sized rockfill with a particle size of 12-15 mm is 10%.

[0019] Preferably, in step S3, for each set of the rockfill aggregates that have completed the established number of wet-dry cycles a uniaxial compression test is carried out, specifically as follows:

[0020] For each set of the rockfill aggregates that have completed the established number of wet-dry cycles of the wet-dry cycle test, they are evenly divided into 10 parts, and then filled into the container of the uniaxial compression test in 10 layers. After each layer is filled, use a rubber mallet to tap the surface of each layer of rockfill to make the surface of each layer of rockfill flat and reach the corresponding scale line of the container, ensuring that the dry density of each layer of rockfill is between 0.88 and 0.89, and then carry out the uniaxial compression test.

[0021] Preferably, in step S3, by analyzing the uniaxial compression curve, the yield stress of each set of the rockfill aggregates that have experienced the established number of wet-dry cycles is determined Specifically as follows:

[0022] Find the position of the maximum curvature value of the uniaxial compression curve, and the axial stress corresponding to this position is the yield stress of the rockfill aggregates .

[0023] Preferably, to find the position of the maximum curvature value of the uniaxial compression curve, specifically as follows:

[0024] The uniaxial compression curve has a starting segment and an ending segment ; among them, the starting segment and the ending segment are both in a straight line form;

[0025] Extend the starting segment and the ending segment respectively to obtain the extended line of the starting segment and the extended line of the ending segment ; the extended line of the starting segment and the extended line of the ending segment intersect at an intersection point ;

[0026] From the intersection point draw a perpendicular line to the extended line of the starting segment and the extended line of the ending segment The angular bisector of the extension line, which intersects the uniaxial compression curve at an intersection point ; the intersection point , which is the position of the maximum curvature of the determined uniaxial compression curve.

[0027] Preferably, step S4 is specifically as follows:

[0028] Step S4.1, assuming that in step S1, the group of rockfill aggregate specimens are respectively subjected to the number of wet-dry cycles being , and through uniaxial compression tests, the corresponding yield stresses obtained are respectively: ; among them, = 0, representing that the rockfill aggregate specimen of the corresponding group is naturally air-dried without undergoing wet-dry cycle tests; , all being greater than or equal to 1;

[0029] Step S4.2, dividing the yield stress respectively by to obtain the yield stress ratio of each group of rockfill aggregate specimens relative to the naturally air-dried rockfill aggregate specimen , which are respectively: ;

[0030] Step S4.3, fitting to obtain the curve of the yield stress ratio varying with the number of wet-dry cycles , thereby establishing a relationship equation - reflecting the relationship between the yield stress ratio and the number of wet-dry cycles : - :

[0031] (2)

[0032] wherein: A, B, and C are respectively the first model parameter, the second model parameter, and the third model parameter of equation (2); exp() represents the natural exponential function;

[0033] Step S4.4, establishing an equation for the uniaxial compression void ratio of the naturally air-dried rockfill aggregate specimen varying with the axial stress :

[0034] (3)

[0035] wherein: , and are respectively the first model parameter, the second model parameter, and the third model parameter of equation (3); p100 is a fixed value of 100 kPa;

[0036] Step S4.5, by combining Equation (2) and Equation (3), a prediction model for the uniaxial compression porosity ratio of the rockfill aggregate considering the influence of the number of wet-dry cycles is constructed: of the rockfill aggregate considering the influence of the number of wet-dry cycles :

[0037] (4)

[0038] Step S4 ends.

[0039] The present invention also provides a system for implementing the prediction method of the uniaxial compression porosity ratio of the rockfill aggregate considering the influence of wet-dry cycles, including:

[0040] A test preparation module, which is used to screen the rockfill particles to screen out multiple groups of rockfill aggregates that meet the particle size distribution characteristics of the rockfill for subsequent tests;

[0041] A wet-dry cycle test device, which is used to perform wet-dry cycle tests on each group of the rockfill aggregates under different established numbers of wet-dry cycles ;

[0042] A uniaxial compression test device, which is used to perform a uniaxial compression test on each group of the rockfill aggregates that have completed the wet-dry cycle test with the established number of wet-dry cycles, to obtain the axial stress corresponding to the established number of wet-dry cycles changing with the axial strain, and by analyzing the uniaxial compression curve, determine the yield stress of each group of the rockfill aggregates after experiencing the established number of wet-dry cycles ; along with the axial strain ; ; ;

[0043] A prediction model construction module, which is used to construct a prediction model for the uniaxial compression porosity ratio of the rockfill aggregate considering the influence of the number of wet-dry cycles according to the yield stress of each group of the rockfill aggregates after experiencing the established number of wet-dry cycles ; ; of the rockfill aggregate considering the influence of the number of wet-dry cycles ;

[0044] A uniaxial compression porosity ratio prediction module, which is used to predict the uniaxial compression porosity ratio of the rockfill aggregate that meets the same particle size distribution characteristics of the rockfill aggregate under different axial stresses after experiencing different numbers of wet-dry cycles ; ; using the prediction model of the uniaxial compression porosity ratio of the rockfill aggregate

[0045] The prediction method and system for the uniaxial compression void ratio of rockfill aggregate considering the influence of wet-dry cycles provided by the present invention have the following advantages:

[0046] The prediction method and system for the uniaxial compression void ratio of rockfill aggregate considering the influence of wet-dry cycles provided by the present invention fully consider the influence of the wet-dry cycle effect caused by the rise and fall of the reservoir water level on the deformation of rockfill, and obtain data that more conforms to the true void ratio of rockfill, providing a scientific and effective means for predicting the deformation of actual rockfill dams during operation under the influence of cyclic changes in reservoir water level. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a flowchart of the prediction method for the uniaxial compression void ratio of rockfill aggregate considering the influence of wet-dry cycles provided by the present invention;

[0048] Figure 2 is a characteristic curve graph of the particle size distribution of rockfill provided by an embodiment of the present invention;

[0049] Figure 3 is the axial stress-axial strain curve graph of the rockfill aggregate provided by an embodiment of the present invention under different numbers of wet-dry cycles ;

[0050] Figure 4 is a schematic diagram of the principle for obtaining the position of the maximum curvature of the uniaxial compression curve provided by an embodiment of the present invention;

[0051] Figure 5 is the yield stress ratio varying with the number of wet-dry cycles of - variation curve graph;

[0052] Figure 6 is the uniaxial compression void ratio of the rockfill aggregate provided by an embodiment of the present invention after the number of wet-dry cycles is 8, 16, 24, 32 times varying with the axial stress curve;

[0053] Figure 7 is the uniaxial compression void ratio of the rockfill aggregate provided by an embodiment of the present invention after 40 times of wet-dry cycle treatment varying with the axial stress measured value of the variation relationship;

[0054] Figure 8 is the uniaxial compression void ratio of the rockfill aggregate provided by an embodiment of the present invention after 40 times of wet-dry cycle treatment under different axial stresses Uniaxial compression void ratio under Comparison diagram between predicted values and test measured data. Specific implementation manners

[0055] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0056] The present invention provides a prediction method and system for the uniaxial compression void ratio of rockfill aggregate considering the influence of wet-dry cycles, fully considering the influence of wet-dry cycles caused by the rise and fall of reservoir water level on the deformation of rockfill, obtaining data that more conforms to the actual void ratio of rockfill, and providing a scientific and effective means for predicting the deformation of actual rockfill dams during operation under the influence of cyclic changes in reservoir water level.

[0057] Through a finite number of test data, the present invention can predict and determine the void ratio of rockfill under uniaxial compression after an unknown number of cycles, providing a reference for predicting the deformation of actual rockfill dams during operation under the influence of cyclic changes in reservoir water level, and having very important significance for ensuring the safe operation of high rockfill dams and the life and property safety of the people downstream.

[0058] As Figure 1 shown, the present invention provides a prediction method for the uniaxial compression void ratio of rockfill aggregate considering the influence of wet-dry cycles, including the following steps:

[0059] Step S1, screening the rockfill particles to select multiple groups of rockfill aggregates that conform to the particle size distribution characteristics of the rockfill; for example, the selected rockfill particles can be divided into 4 to 5 groups of rockfill aggregates.

[0060] In the present invention, the particle size distribution characteristics of the rockfill particles may be the particle size distribution characteristics that conform to formula (1):

[0061] (1)

[0062] Where: d is the particle size of the rockfill particles in the set particle size range; is the gamma function; P0, , , d c and m are the first model parameter, second model parameter, third model parameter, fourth model parameter and fifth model parameter of formula (1) respectively; P is the mass percentage of the corresponding rockfill particle size d in the rockfill aggregate.

[0063] For example, the set particle size range is 5 to 15 mm; the first model parameter P0, the second model parameter , the third model parameter , the fourth model parameter d c and the fifth model parameter m are set to -13.9, 1292, 10, 14, and 170 respectively.

[0064] Then: the obtained particle size distribution characteristics of the rockfill are as follows: the mass percentage of small-sized rockfill with a particle size of 5 - 7 mm is 20%; the mass percentage of medium-sized rockfill with a particle size of 7 - 12 mm is 70%; the mass percentage of large-sized rockfill with a particle size of 12 - 15 mm is 10%.

[0065] Step S2, conduct wet-dry cycling tests on each group of the rockfill aggregates under different established numbers of wet-dry cycles ;

[0066] Step S3, conduct uniaxial compression tests on each group of the rockfill aggregates that have completed the wet-dry cycling tests with the established number of wet-dry cycles, and obtain the axial stress corresponding to the established number of wet-dry cycles changing with the axial strain The uniaxial compression curve. By analyzing the uniaxial compression curve, determine the yield stress of each group of the rockfill aggregates after experiencing the established number of wet-dry cycles ; ;

[0067] In this step, when conducting uniaxial compression tests on each group of the rockfill aggregates that have completed the wet-dry cycling tests with the established number of wet-dry cycles, specifically:

[0068] Divide each group of the rockfill aggregates that have completed the wet-dry cycling tests with the established number of wet-dry cycles into 10 parts evenly, and then fill them into the container for the uniaxial compression test in 10 layers. After each layer is filled, use a rubber mallet to tap the surface of each layer of the rockfill to make the surface of each layer of the rockfill flat and reach the corresponding scale line of the container, ensuring that the dry density of each layer of the rockfill is between 0.88 and 0.89, and then conduct the uniaxial compression test.

[0069] In this step, by analyzing the uniaxial compression curve, determine the yield stress of each group of the rockfill aggregates after experiencing the established number of wet-dry cycles Specifically:

[0070] Obtain the position of the maximum curvature value of the uniaxial compression curve, and the axial stress corresponding to this position is the yield stress of the rockfill aggregate.

[0071] Find the position of the maximum curvature of the uniaxial compression curve, specifically:

[0072] The uniaxial compression curve has a starting segment and an ending segment ; among them, the starting segment and the ending segment are both in a straight-line form;

[0073] Extend the starting segment and the ending segment , to obtain the extended line of the starting segment and the extended line of the ending segment ; the extended line of the starting segment and the extended line of the ending segment intersect at an intersection point ;

[0074] From the intersection point draw the angular bisector of the extended line of the starting segment and the extended line of the ending segment , and intersect it with the uniaxial compression curve at an intersection point ; the intersection point is the determined position of the maximum curvature of the uniaxial compression curve.

[0075] Step S4. According to the yield stress of each set of the rockfill aggregate after undergoing a given number of wet-dry cycles obtained in step S3, construct a prediction model for the uniaxial compression void ratio of the rockfill aggregate considering the influence of the number of wet-dry cycles ;

[0076] Step S4 is specifically as follows:

[0077] Step S4.1. Assume that the groups of rockfill aggregates screened in step S1 are respectively subjected to wet-dry cycles times of , and through uniaxial compression tests, the corresponding yield stresses obtained are respectively: ; among them, = 0 represents that the corresponding group of rockfill aggregates is air-dried naturally without undergoing wet-dry cycle tests; , are all greater than or equal to 1;

[0078] Step S4.2. Divide the yield stress by respectively to obtain the yield stress ratios of each group of rockfill aggregates relative to the air-dried naturally rockfill aggregate, which are respectively: ;

[0079] Step S4.3, fitting to obtain the yield stress ratio with the number of dry-wet cycles of - variation curve, thereby establishing the relationship equation between the reaction yield stress ratio and the number of dry-wet cycles as follows: - relationship equation:

[0080] (2)

[0081] wherein: A, B, and C are the first model parameter, the second model parameter, and the third model parameter of equation (2) respectively; exp() represents the natural exponential function; the yield stress ratio can reflect the deterioration degree of the mechanical properties of the reactor fill.

[0082] Step S4.4, establishing the equation for the variation of the uniaxial compression void ratio of the air-dried reactor fill aggregate with the axial stress as follows:

[0083] (3)

[0084] wherein: , and are the first model parameter, the second model parameter, and the third model parameter of equation (3) respectively; p 100 is a fixed value of 100 kPa;

[0085] Step S4.5, combining equation (2) and equation (3), constructing a prediction model for the uniaxial compression void ratio of the reactor fill aggregate considering the influence of the number of dry-wet cycles as follows:

[0086] (4)

[0087] Step S4 ends.

[0088] Step S5, using the prediction model of the uniaxial compression void ratio of the reactor fill aggregate, predicting the uniaxial compression void ratio of the reactor fill aggregate with the same particle size distribution characteristics of the reactor fill after experiencing different numbers of dry-wet cycles at different axial stresses when

[0089] The following introduces an embodiment:

[0090] In this embodiment, taking the dam filling rockfill of a certain core wall rockfill dam as an example, the uniaxial compression void ratio under uniaxial compression after different numbers of wet-dry cycles is predicted. The uniaxial compression void ratio is predicted.

[0091] Step S1: Screen the rockfill particles to select multiple groups of rockfill aggregates that conform to the particle size distribution characteristics of the rockfill.

[0092] Specifically, the particle size distribution characteristics of the rockfill particles are the particle size distribution characteristics that conform to formula (1):

[0093] (1)

[0094] where: d is the particle size of the rockfill particles in the particle size range of 5 - 15 mm; the first model parameter P0, the second model parameter , the third model parameter , the fourth model parameter d c and the fifth model parameter m are set to -13.9, 1292, 10, 14, and 170 respectively.

[0095] In this embodiment, the selected rockfill particles are divided into 5 groups of rockfill aggregates. After calculation by formula (1), the particle size distribution characteristic curves of each group of rockfill aggregates are as Figure 2 shown. The particle size distribution characteristics of the rockfill particles are: the mass percentage of small-sized rockfill particles with a particle size of 5 - 7 mm is 20%; the mass percentage of medium-sized rockfill particles with a particle size of 7 - 12 mm is 70%; the mass percentage of large-sized rockfill particles with a particle size of 12 - 15 mm is 10%.

[0096] Step S2: Conduct wet-dry cycle tests on each group of the rockfill aggregates under different established numbers of wet-dry cycles ;

[0097] In this embodiment, for the 5 groups of rockfill aggregates, the first group of rockfill aggregates is naturally air-dried without undergoing wet-dry cycle tests. Therefore, the number of wet-dry cycles is 0 times; for the second to fourth groups of rockfill aggregates, the wet-dry cycle test method is: set the time for one wetting and one air-drying to 24 h each, that is, the rockfill aggregates are recorded as having completed one wet-dry cycle after 24 h of wetting and 24 h of air-drying. And for the second to fourth groups of rockfill aggregates, the numbers of wet-dry cycles are 8, 16, 24, and 32 times respectively. After completing the corresponding number of wet-dry cycle tests, take them out from the wet-dry cycle testing machine.

[0098] Step S3: For each group that has completed the established number of wet-dry cycles The uniaxial compression test is carried out on the aggregate of rockfill materials in the wet-dry cycle test to obtain the established number of wet-dry cycles The corresponding axial stress varying with the axial strain uniaxial compression curve;

[0099] In this embodiment, the uniaxial compression test is respectively carried out on 5 groups of aggregate of rockfill materials with the number of wet-dry cycles being 0 times, and those experiencing the number of wet-dry cycles being 8, 16, 24, and 32 times respectively. The displacement loading method is used for quasi-static loading until the target axial stress is reached, and the Figure 3 axial stress-axial strain curve diagrams under different numbers of wet-dry cycles as shown are obtained, which are the uniaxial compression curves.

[0100] By analyzing the uniaxial compression curve, the yield stress of the aggregate of rockfill materials after each group experiences the established number of wet-dry cycles is determined; specifically, the position of the maximum curvature value of the uniaxial compression curve is obtained, and the axial stress corresponding to this position is the yield stress of the aggregate of rockfill materials.

[0101] The method for obtaining the position of the maximum curvature value of the uniaxial compression curve is as follows: As Figure 4 shown, the uniaxial compression curve has a starting segment and an ending segment ; among them, both the starting segment and the ending segment are in a straight line form; the starting segment and the ending segment are respectively extended to obtain the extended line of the starting segment and the extended line of the ending segment ; the extended line of the starting segment and the extended line of the ending segment intersect at an intersection point ; from the intersection point a bisector of the angle between the extended line of the starting segment and the extended line of the ending segment is made and intersects with the uniaxial compression curve at an intersection point ; the intersection point is the determined position of the maximum curvature value of the uniaxial compression curve.

[0102] Step S4, according to the yield stress of the aggregate of rockfill materials after each group experiences the established number of wet-dry cycles obtained in step S3 , a prediction model of the uniaxial compression void ratio of the rockfill aggregate considering the number of wet-dry cycles is constructed affected is obtained ;

[0103] Step S4.1, for the 5 groups of rockfill aggregates screened in Step S1, after the number of wet-dry cycles is 0, 8, 16, 24, 32 times, through uniaxial compression tests, the corresponding yield stresses obtained are respectively: ;

[0104] Step S4.2, divide the yield stress , respectively, by , to obtain the yield stress ratio of each group of rockfill aggregates relative to the naturally air-dried rockfill aggregate , which are respectively: ; Obviously, is equal to 1;

[0105] Step S4.3, fit to obtain the yield stress ratio as shown in Figure 5 changes with the number of wet-dry cycles as changes, so as to establish a relationship equation reflecting the relationship between the yield stress ratio - and the number of wet-dry cycles and the number of wet-dry cycles : - relationship equation:

[0106] (2)

[0107] where: A, B, and C are the first model parameter, the second model parameter, and the third model parameter of equation (2), which are respectively: 0.369, 0.001, -0.102 in this embodiment; exp() represents the natural exponential function;

[0108] Step S4.4, establish an equation for the change of the uniaxial compression void ratio of the naturally air-dried rockfill aggregate with the axial stress :

[0109] (3)

[0110] where: , and are the first model parameter, the second model parameter, and the third model parameter of equation (3); p 100 is a fixed value of 100 kPa; through the uniaxial compression test results of the naturally air-dried rockfill aggregate and its uniaxial compression void ratio The test data can be used to determine e0, and the values of D are 1.25, 0.18, and 661 respectively.

[0111] Step S4.5: Through the analysis of test data, obtain Figure 6 the uniaxial compression void ratio of the rockfill aggregate after the number of wet-dry cycles shown in Figure 8, 16, 24, and 32 times; varying with the axial stress variation curve;

[0112] For Figure 6 the variation curve, combine with Equation (2) and Equation (3), and construct a prediction model for the uniaxial compression void ratio of the rockfill aggregate considering the influence of the number of wet-dry cycles as follows:

[0113] (4)

[0114] Substitute the model parameters determined in this embodiment to obtain the prediction model for the uniaxial compression void ratio as:

[0115] (5)

[0116] Step 5: Use the prediction model of formula (5) to predict the uniaxial compression void ratio of the rockfill aggregate with the same particle size distribution characteristics of the rockfill after experiencing different numbers of wet-dry cycles at different axial stresses when.

[0117] In this embodiment, set the number of wet-dry cycles to 40 times. Through formula 5, directly predict that when the axial stress is 10 kPa, 100 kPa, 500 kPa, 1000 kPa, 5000 kPa, and 10000 kPa, the predicted values of the uniaxial compression void ratio are 0.905, 0.863, 0.747, 0.663, 0.414, and 0.295 respectively.

[0118] As a verification, conduct an experiment on the rockfill aggregate with the same particle size distribution characteristics of the rockfill for 40 wet-dry cycles, and then conduct a uniaxial compression test on it to obtain Figure 7 the relationship diagram of the uniaxial compression void ratio of the rockfill aggregate after 40 wet-dry cycles varying with the axial stress . From Figure 7It can be obtained that under axial stresses of 10 kPa, 100 kPa, 500 kPa, 1000 kPa, 5000 kPa and 10000 kPa, the uniaxial compression void ratios of the rockfill aggregate are 0.896, 0.871, 0.782, 0.690, 0.433 and 0.308 respectively.

[0119] As Figure 8 shown, it is a comparison chart of the predicted values and the test measured data of the uniaxial compression void ratios of the rockfill aggregate after 40 wet-dry cycles under different axial stresses. From it can be seen that the errors between the predicted results of the present invention and the test measured data results are all less than 5%, meeting the requirements of the model prediction accuracy. Figure 8

[0120] The present invention also provides a system for implementing a prediction method for the uniaxial compression void ratio of a rockfill aggregate considering the influence of wet-dry cycles, which is used to automatically implement the prediction method for the uniaxial compression void ratio of a rockfill aggregate considering the influence of wet-dry cycles provided by the present invention, including:

[0121] A test preparation module, which is used to execute the content described in step S1 above, and is used to screen the rockfill particles to screen out multiple groups of rockfill aggregates that meet the particle size distribution characteristics of the rockfill for subsequent tests;

[0122] A wet-dry cycle test device, which is used to execute the content described in step S2 above, and is used to perform wet-dry cycle tests on each group of the rockfill aggregates under different established numbers of wet-dry cycles ;

[0123] A uniaxial compression test device, which is used to execute the content described in step S3 above, and is used to perform uniaxial compression tests on each group of the rockfill aggregates that have completed the wet-dry cycle tests with the established number of wet-dry cycles, and obtain the axial stress corresponding to the established number of wet-dry cycles changing with the axial strain . By analyzing the uniaxial compression curve, the yield stress of each group of the rockfill aggregates after experiencing the established number of wet-dry cycles is determined; ;

[0124] A prediction model construction module, which is used to execute the content described in step S4 above, and is used to construct, according to the yield stress of each group of the rockfill aggregates after experiencing the established number of wet-dry cycles , a prediction model considering the number of wet-dry cycles​ Uniaxial compression void ratio of the affected rockfill aggregate Prediction model;

[0125] Uniaxial compression void ratio prediction module, used to execute the content described in step S5 above, and used to adopt the uniaxial compression void ratio of the rockfill aggregate Prediction model, for predicting the uniaxial compression void ratio of rockfill aggregates that conform to the same particle size distribution characteristics of rockfill materials after experiencing different numbers of wet-dry cycles Under different axial stresses Uniaxial compression void ratio For prediction.

[0126] Furthermore, it may further include an input display module and a control module:

[0127] Input display module, used to receive control instructions input by the operator and display corresponding information according to the control instructions. For example, display the input, output data and processing process of each module in the form of text, table or static or dynamic graph, two-dimensional or three-dimensional model diagram.

[0128] Control module, communicatively connected to the test preparation module, wet-dry cycle test device, uniaxial compression test device, prediction model construction module, uniaxial compression void ratio prediction module, and input display module, to control the operation of each module.

[0129] The prediction method and system for the uniaxial compression void ratio of rockfill aggregates considering the influence of wet-dry cycles involved in the present invention propose a prediction model for the uniaxial compression void ratio of rockfill aggregates under different numbers of wet-dry cycles. By substituting the data obtained from the test into this model to determine each parameter, the final prediction model can be obtained. Through this prediction model, the uniaxial compression void ratio of rockfill aggregates under any number of wet-dry cycles can be predicted, providing accurate and reliable data for the deformation of actual rockfill dams during operation under the cyclic change of reservoir water level. For example, it is used to determine the uniaxial compression void ratio and deformation of the rockfill materials for building a core rockfill dam after experiencing wet-dry cycles caused by the cyclic rise and fall of the reservoir water level.

[0130] Moreover, the present invention only needs to perform wet-dry cycle treatments on 4 to 5 groups of rockfill aggregates with the same particle size distribution, and conduct uniaxial compression tests on the rockfill particles after the wet-dry cycle action to determine the model parameters. It has low requirements for test equipment, few test times, simple operation, can effectively save test materials and time, and improves work efficiency.

[0131] The solution of the present invention is particularly applicable to the design stage of rockfill dam projects.

[0132] Specifically, in the design stage of a rockfill dam project, the method of the present invention is used to first determine a rockfill material assembly that meets certain rockfill material particle distribution characteristics for the test, and then conduct a dry-wet cycle test and a uniaxial compression test on the rockfill material assembly to obtain a dry-wet cycle test. Uniaxial compression porosity ratio of rockfill aggregates The prediction model is used to predict the influence of different dry-wet cycles on the axial stress. Uniaxial compression porosity ratio of rockfill materials , determine the uniaxial compression porosity of rockfill materials Whether it meets the design requirements of the rockfill dam project; if so, it can be recommended to use rockfill materials that meet the particle distribution characteristics of this rockfill material for dam construction. If not, the specific data of the rockfill material particle distribution characteristics of the rockfill material aggregate is replaced, and the uniaxial compression porosity ratio is recycled. The prediction until the uniaxial compression porosity ratio Therefore, the solution provided by the present invention can provide reference data for the selection of rockfill material assemblies in the design stage of rockfill dam engineering and guide the selection of rockfill material particles for dam construction.

[0133] In summary, the present invention can achieve accuracy and efficiency in predicting the uniaxial compression porosity of rockfill aggregates.

[0134] The above embodiments are merely examples of the technical solutions of the present invention. The method and device for predicting the uniaxial compression porosity ratio of rockfill aggregates considering the influence of dry-wet cycles involved in the present invention are not limited to the contents described in the above embodiments, but are subject to the scope defined in the claims. Any modification, supplement or equivalent replacement made by technicians in the field of the present invention based on the embodiment is within the scope of protection required by the claims of the present invention.

Claims

1. A prediction method for the uniaxial compression void ratio of rockfill aggregate considering the influence of wet-dry cycles, characterized in that, It includes the following steps: Step S1: Screen the rockfill particles to select multiple groups of rockfill aggregates that conform to the particle size distribution characteristics of the rockfill; Step S2, perform wet-dry cycle tests on each group of the aggregate of the rockfill materials under different established numbers of wet-dry cycles ; Step S3, for each group that has completed the established number of wet-dry cycles of the aggregate of rockfill materials in the wet-dry cycle test, perform a uniaxial compression test to obtain the axial stress corresponding to the established number of wet-dry cycles ; Analyze the uniaxial compression curve by analyzing the uniaxial compression curve to determine the yield stress of the aggregate of rockfill materials after each group has experienced the established number of wet-dry cycles ; ​ Step S4: According to the yield stress of each set of the rockfill aggregate after undergoing a given number of wet-dry cycles obtained in Step S3 to construct a prediction model for the uniaxial compression void ratio of the rockfill aggregate considering the influence of the number of wet-dry cycles ; ​​ Step S4 specifically is: Step S4.1, assume that in Step S1, the group of rockfill aggregate is respectively subjected to the number of wet-dry cycles being , and through uniaxial compression tests, the corresponding yield stresses obtained are respectively: ; among them, =0 represents that the rockfill aggregate of the corresponding group is naturally air-dried without wet-dry cycle tests; , all are greater than or equal to 1; Step S4.2, divide the yield stress , respectively, by to obtain the yield stress ratios of each group of rockfill aggregate relative to the naturally air-dried rockfill aggregate , which are respectively ; Step S4.3, fitting to obtain the yield stress ratio with the number of dry-wet cycles of - variation curve, thereby establishing the relationship equation between the yield stress ratio and the number of dry-wet cycles - : （2） Where: A, B, and C are the first model parameter, the second model parameter, and the third model parameter of Equation (2) respectively; exp() represents the natural exponential function; Step S4.4, establish the equation of the uniaxial compression void ratio of the naturally air-dried aggregate of rockfill materials varying with the axial stress : （3） Wherein: , and are the first model parameter, the second model parameter, and the third model parameter of Equation (3), respectively; p 100 is a fixed value of 100 kPa; Step S4.5, combining Equation (2) and Equation (3), construct the uniaxial compression void ratio of the rockfill aggregate considering the influence of the number of wet-dry cycles of the prediction model: affected （4） Step S4 ends; Step S5: Using the prediction model of the uniaxial compression void ratio of the said rockfill aggregate to predict the uniaxial compression void ratio of rockfill aggregates that conform to the same particle size distribution characteristics of rockfill materials after undergoing different numbers of wet-dry cycles and under different axial stresses . ​ 2. The prediction method for the uniaxial compression void ratio of the rockfill aggregate considering the influence of wet-dry cycles according to claim 1, characterized in that In Step S1, the particle size distribution characteristics of the rockfill particles are the particle size distribution characteristics that conform to Formula (1): （1） Where: d is the particle size of the rockfill particles in the set particle size range; is the gamma function; P0, , , d c and m are the first model parameter, the second model parameter, the third model parameter, the fourth model parameter, and the fifth model parameter of formula (1), respectively; P is the mass percentage of the rockfill particles with the particle size d in the rockfill aggregate.

3. The prediction method of the uniaxial compression void ratio of the rockfill aggregate considering the influence of wet-dry cycles according to claim 2, characterized in that, Set the particle size range to 5 - 15 mm; the first model parameter P0, the second model parameter , the third model parameter , the fourth model parameter d c and the fifth model parameter m are set to -13.9, 1292, 10, 14, and 170 respectively.

4. The prediction method for the uniaxial compression void ratio of rockfill aggregate considering the influence of dry-wet cycles according to claim 1, characterized in that The selected rockfill particles are divided into 4 to 5 groups of rockfill aggregates.

5. The prediction method for the uniaxial compression void ratio of rockfill aggregate considering the influence of dry-wet cycles according to claim 1, characterized in that The particle size distribution characteristics of the rockfill particles are: the mass percentage of small-sized rockfill with a particle size of 5 to 7 mm is 20%; the mass percentage of medium-sized rockfill with a particle size of 7 to 12 mm is 70%; the mass percentage of large-sized rockfill with a particle size of 12 to 15 mm is 10%.

6. The prediction method of the uniaxial compression porosity ratio of the rockfill aggregate considering the influence of wet-dry cycles according to claim 1, characterized in that, In step S3, for each group of the rockfill aggregate that has completed the established number of wet-dry cycles a uniaxial compression test is carried out, specifically as follows: For each group of the aggregate of rockfill materials that has completed the established number of wet-dry cycles in the wet-dry cycle test, it is evenly divided into 10 parts and then filled into the container for the uniaxial compression test in 10 layers. After each layer is filled, use a rubber mallet to tap the surface of the rockfill materials in each layer to make the surface of each layer of rockfill materials flat and reach the corresponding scale line of the container, ensuring that the dry density of each layer of rockfill materials is between 0.88 and 0.89, and then conduct the uniaxial compression test.

7. The prediction method of the uniaxial compression void ratio of the rockfill aggregate considering the influence of dry-wet cycles according to claim 1, characterized in that, In step S3, by analyzing the uniaxial compression curve, the yield stress of the rockfill aggregate after each group has experienced a predetermined number of wet-dry cycles is determined. Specifically, it is as follows: Determine the position of the maximum curvature of the uniaxial compression curve, and the axial stress corresponding to this position is the yield stress of the rockfill aggregate .

8. The prediction method for the uniaxial compression void ratio of the rockfill aggregate considering the influence of wet-dry cycles according to claim 7, characterized in that, Obtain the position of the maximum curvature of the uniaxial compression curve, specifically: The uniaxial compression curve has a starting segment and an ending segment ; among them, the starting segment and the ending segment are both in a straight line form; Extend the starting segment and the ending segment respectively and the ending segment to obtain the extension line of the starting segment and the extension line of the ending segment ; The extension line of the starting segment and the extension line of the ending segment intersect at the intersection point ; From the intersection point Construct the starting segment The extension line and the ending segment The angular bisector of the extension line, which intersects with the uniaxial compression curve at an intersection point ; The intersection point is the position of the maximum curvature of the determined uniaxial compression curve.

9. A system for predicting the uniaxial compression void ratio of a rockfill aggregate considering the influence of wet-dry cycles according to any one of claims 1 to 8, characterized in that, It includes: The test preparation module is used to screen the rockfill particles to select multiple groups of rockfill aggregates that conform to the particle size distribution characteristics of the rockfill for subsequent tests; A dry-wet cycling test device for performing dry-wet cycling tests on each group of the aggregate of rockfill materials with different established dry-wet cycling times under the dry-wet cycling test; Uniaxial compression test device, used to perform uniaxial compression tests on the aggregate of rockfill materials that have completed the established wet-dry cycle tests for each group, to obtain the axial stress corresponding to the established number of wet-dry cycles and the uniaxial compression curve that changes with the axial strain. By analyzing the uniaxial compression curve, the yield stress of the aggregate of rockfill materials after each group has experienced the established number of wet-dry cycles is determined ; ;​​​ A prediction model construction module, which is used to construct a prediction model of the uniaxial compression void ratio of the rockfill aggregate considering the influence of the number of wet-dry cycles according to the yield stress of each group of the obtained rockfill aggregates after a given number of wet-dry cycles of the rockfill aggregate after a given number of wet-dry cycles, and construct a prediction model of the uniaxial compression void ratio of the rockfill aggregate considering the influence of the number of wet-dry cycles ; Uniaxial compression porosity ratio prediction module, which is used to adopt the uniaxial compression porosity ratio of the rockfill aggregate prediction model to predict the uniaxial compression porosity ratio of the rockfill aggregate that conforms to the same particle size distribution characteristics of the rockfill after experiencing different numbers of wet-dry cycles and under different axial stresses ​​

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