Prediction method and system for uniaxial compression void ratio of rockfill material aggregate considering dry-wet cycle influence

Abstract

The invention provides a prediction method and system for a uniaxial compression void ratio of a rockfill material aggregate considering dry-wet cycle influence. The prediction method comprises the following steps: screening out a plurality of groups of rockfill material aggregates conforming to the particle size distribution characteristics of rockfill material particles; carrying out dry-wet cycle tests under different set dry-wet cycle times N; carrying out a uniaxial compression test; a prediction model of the uniaxial compression void ratio e of the rockfill material aggregate considering the influence of the number N of dry-wet cycles is constructed; and predicting the uniaxial compression void ratio e of the rockfill material aggregate conforming to the same rockfill material particle size distribution characteristics under different axial stresses sigma v after the rockfill material aggregate is subjected to different dry-wet cycle times N. According to the method, the influence of the dry-wet cycle effect caused by reservoir water level rising and falling on rockfill material deformation is fully considered, data more conforming to the real void ratio of the rockfill material is obtained, and a scientific and limited means is provided for predicting deformation of an actual rockfill dam project under the influence of reservoir water level cycle change during operation.

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 system for predicting the uniaxial compression porosity ratio of a rockfill aggregate 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 a dry-wet cycle test on each group of rockfill material assemblies at different predetermined dry-wet cycle numbers N;

[0010] Step S3, performing a uniaxial compression test on each group of rockfill material assemblies that have completed a predetermined number of dry-wet cycles N, and obtaining an axial stress σ corresponding to the predetermined number of dry-wet cycles N. v With axial strain ε v The yield stress σ of the rockfill aggregate after each group of dry-wet cycles N is determined by analyzing the uniaxial compression curve. y ;

[0011] Step S4, according to the yield stress σ of each group of rockfill aggregates after undergoing a predetermined number of dry-wet cycles N obtained in step S3 y , a prediction model for the uniaxial compression porosity e of rockfill aggregates considering the influence of the number of dry-wet cycles N was constructed;

[0012] Step S5, using the prediction model of the uniaxial compression porosity e of the rockfill aggregate, the rockfill aggregates with the same rockfill particle size distribution characteristics are subjected to different dry-wet cycles N under different axial stresses σ v The uniaxial compression porosity e is predicted.

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

[0014]

[0015] Where: d is the particle size of the rockfill material in the set particle size range; Γ is the gamma function; P 0 ,γ,ω,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; and 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 to 15 mm; the first model parameter P 0 , the second model parameter γ, the third model parameter ω, 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 material are as follows: the mass percentage of small-size rockfill material of 5-7 mm is 20%; the mass percentage of medium-size rockfill material of 7-12 mm is 70%; the mass percentage of large-size rockfill material of 12-15 mm is 10%.

[0019] Preferably, in step S3, a uniaxial compression test is performed on each group of the rockfill material assemblies that have completed a predetermined number of dry-wet cycles N, specifically:

[0020] Each group of the rockfill material aggregates that have completed the predetermined number of dry-wet cycles N is evenly divided into 10 parts, and then filled into the container of the uniaxial compression test in 10 layers. After each layer is filled, the surface of each layer of rockfill material is knocked with a rubber mallet to make the surface of each layer of rockfill material flat and reach the corresponding scale line of the container, ensuring that the dry density of each layer of rockfill material is between 0.88 and 0.89, and then the uniaxial compression test is carried out.

[0021] Preferably, in step S3, the yield stress σ of the rockfill material assembly after each group of dry-wet cycles N is determined by analyzing the uniaxial compression curve. y Specifically:

[0022] Find the position of the maximum curvature of the uniaxial compression curve, and the axial stress σ corresponding to this position is v The yield stress σ of the rockfill aggregate is y .

[0023] Preferably, the position of the maximum curvature of the uniaxial compression curve is obtained as follows:

[0024] The uniaxial compression curve has a starting segment OM and a terminal segment O'M'; wherein the starting segment OM and the terminal segment O'M' are both straight line types;

[0025] The starting segment OM and the ending segment O'M' are respectively extended to obtain an extension line of the starting segment OM and an extension line of the ending segment O'M'; the extension line of the starting segment OM and the extension line of the ending segment O'M' intersect at an intersection point Y';

[0026] From the intersection point Y', the angle bisector of the extension line of the starting segment OM and the extension line of the ending segment O'M' is drawn, and intersects with the uniaxial compression curve at the intersection point Y; the intersection point Y is the position of the maximum curvature of the uniaxial compression curve.

[0027] Preferably, step S4 is specifically:

[0028] Step S4.1: Assume that n+1 groups of rockfill material aggregates are screened out in step S1, and the number of dry-wet cycles N for each group is N. 0 ,N 1 , N 2 ,...,N n , through uniaxial compression test, the corresponding yield stresses are: σ y0 ,σ y1 ,σ y2 ,...,σyn ; Among them, N 0 =0, indicating that the rockfill aggregate of the corresponding group is naturally air-dried without dry-wet cycle test; N 1 , N 2 ,...,N n , are both greater than or equal to 1;

[0029] Step S4.2, the yield stress σ y0 ,σ y1 ,σ y2 ,...,σ yn , divided by σ y0 , the yield stress ratios k of each group of rockfill aggregates relative to the naturally air-dried rockfill aggregates are obtained as follows: k 0 ,k 1 ,k 2 ,...,k n ;

[0030] Step S4.3, fitting the kN variation curve of the yield stress ratio k with the number of dry-wet cycles N, thereby establishing the kN relationship equation for the relationship between the reaction yield stress ratio k and the number of dry-wet cycles N:

[0031] k=A(1-exp -BN ) C (2)

[0032] Where: A, B, C are the first model parameter, the second model parameter and the third model parameter of equation (2) respectively; e is the base of the natural logarithm function;

[0033] Step S4.4, establish the uniaxial compression porosity e of the naturally air-dried rockfill aggregate as a function of axial stress σ v The changing equation is:

[0034]

[0035] Where: e 0 , λ and D are the first model parameter, the second model parameter and the third model parameter of equation (3) respectively; p 100 is a fixed value;

[0036] Step S4.5, combining equation (2) and equation (3), construct a prediction model for the uniaxial compression porosity e of the rockfill aggregate considering the influence of the number of dry-wet cycles N:

[0037]

[0038] Step S4 ends.

[0039] The present invention also provides a system for realizing the method for predicting the uniaxial compression porosity ratio of rockfill aggregates considering the influence of dry-wet cycles, comprising:

[0040] The test preparation module is used to screen the rockfill material particles and select multiple groups of rockfill material aggregates that meet the particle size distribution characteristics of the rockfill material for subsequent tests;

[0041] A dry-wet cycle test device, used to perform dry-wet cycle tests on each group of rockfill material assemblies at different predetermined dry-wet cycle numbers N;

[0042] The uniaxial compression test device is used to perform a uniaxial compression test on each group of rockfill material aggregates that have completed a predetermined number of dry-wet cycles N, and obtain the axial stress σ corresponding to the predetermined number of dry-wet cycles N. v With axial strain ε v The yield stress σ of the rockfill aggregate after each group of dry-wet cycles N is determined by analyzing the uniaxial compression curve. y ;

[0043] The prediction model building module is used to obtain the yield stress σ of the rockfill aggregate after each group of predetermined dry-wet cycles N. y , a prediction model for the uniaxial compression porosity e of rockfill aggregates considering the influence of the number of dry-wet cycles N was constructed;

[0044] The uniaxial compression porosity prediction module is used to use the prediction model of the uniaxial compression porosity e of the rockfill aggregate to predict the porosity of the rockfill aggregate with the same rockfill particle size distribution characteristics under different axial stresses σ after experiencing different dry-wet cycles N. v The uniaxial compression porosity e is predicted.

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

[0046] The present invention provides a method and system for predicting the uniaxial compression porosity of a rockfill aggregate taking into account the influence of dry-wet cycles, fully considering the influence of dry-wet cycles caused by reservoir water level rise and fall on the deformation of the rockfill, obtaining data that is more consistent with the actual porosity of the rockfill, and providing a scientific and limited means for predicting the deformation of an actual rockfill dam project under the influence of reservoir water level cycle changes during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A flow chart of a method for predicting the uniaxial compression porosity ratio of rockfill aggregates taking into account the influence of dry-wet cycles provided by the present invention;

[0048] Figure 2 A characteristic curve diagram of particle size distribution of rockfill material particles provided in an embodiment of the present invention;

[0049] Figure 3 Axial stress-axial strain curve diagram of the rockfill material assembly under different dry-wet cycle numbers N provided by an embodiment of the present invention;

[0050] Figure 4 A schematic diagram of obtaining the maximum curvature position of a uniaxial compression curve provided in an embodiment of the present invention;

[0051] Figure 5 A curve diagram showing a change in kN of the yield stress ratio k with the number of dry-wet cycles N provided in an embodiment of the present invention;

[0052] Figure 6 The uniaxial compression porosity e of the rockfill aggregate after the number of dry-wet cycles N is 8, 16, 24, and 32 provided in the embodiment of the present invention varies with the axial stress σ v Change curve;

[0053] Figure 7 The uniaxial compression porosity ratio e of the rockfill aggregate after 40 dry-wet cycles provided by the embodiment of the present invention varies with the axial stress σ v The measured value of the change relationship;

[0054] Figure 8 The rockfill material aggregate after 40 dry-wet cycles provided by the embodiment of the present invention is subjected to different axial stresses σ v Comparison chart of the predicted value of the uniaxial compression porosity e and the experimental measured data. DETAILED DESCRIPTION

[0055] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying 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 method and system for predicting the uniaxial compression porosity of a rockfill aggregate taking into account the influence of dry-wet cycles, fully considering the influence of dry-wet cycles caused by reservoir water level rise and fall on the deformation of the rockfill, obtaining data that is more consistent with the actual porosity of the rockfill, and providing a scientific and limited means for predicting the deformation of an actual rockfill dam project under the influence of reservoir water level cycle changes during operation.

[0057] The present invention can predict and determine the porosity of rockfill materials under uniaxial compression after an unknown number of cycles through a limited number of test data, which provides a reference for predicting the deformation of actual rockfill dam projects under the influence of cyclic changes in reservoir water levels during operation, and is of great significance for ensuring the safe operation of high rockfill dams and the safety of life and property of the people downstream.

[0058] like Figure 1 As shown, the present invention provides a method for predicting the uniaxial compression porosity of a rockfill aggregate taking into account the influence of dry-wet cycles, comprising the following steps:

[0059] Step S1, screening the rockfill material particles to screen out multiple groups of rockfill material assemblies that meet the particle size distribution characteristics of the rockfill material particles; for example, the screened rockfill material particles can be divided into 4 to 5 groups of rockfill material assemblies.

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

[0061]

[0062] Where: d is the particle size of the rockfill material in the set particle size range; Γ is the gamma function; P 0 ,γ,ω,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; and P is the mass percentage of the corresponding rockfill material particle size d in the rockfill material aggregate.

[0063] For example, the particle size range is set to 5 to 15 mm; the first model parameter P 0 , the second model parameter γ, the third model parameter ω, 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 particle size distribution characteristics of the rockfill material are as follows: the mass percentage of small-size rockfill material of 5-7 mm is 20%; the mass percentage of medium-size rockfill material of 7-12 mm is 70%; and the mass percentage of large-size rockfill material of 12-15 mm is 10%.

[0065] Step S2, performing a dry-wet cycle test on each group of rockfill material assemblies at different predetermined dry-wet cycle numbers N;

[0066] Step S3, performing a uniaxial compression test on each group of rockfill material assemblies that have completed a predetermined number of dry-wet cycles N, and obtaining an axial stress σ corresponding to the predetermined number of dry-wet cycles N. v With axial strain ε vThe yield stress σ of the rockfill aggregate after each group of dry-wet cycles N is determined by analyzing the uniaxial compression curve. y ;

[0067] In this step, a uniaxial compression test is performed on each group of the rockfill material assemblies that have completed a predetermined number of dry-wet cycles N, specifically:

[0068] Each group of the rockfill material aggregates that have completed the predetermined number of dry-wet cycles N is evenly divided into 10 parts, and then filled into the container of the uniaxial compression test in 10 layers. After each layer is filled, the surface of each layer of rockfill material is knocked with a rubber mallet to make the surface of each layer of rockfill material flat and reach the corresponding scale line of the container, ensuring that the dry density of each layer of rockfill material is between 0.88 and 0.89, and then the uniaxial compression test is carried out.

[0069] In this step, the yield stress σ of the rockfill aggregate after each group of dry-wet cycles N is determined by analyzing the uniaxial compression curve. y Specifically:

[0070] Find the position of the maximum curvature of the uniaxial compression curve, and the axial stress σ corresponding to this position is v The yield stress σ of the rockfill aggregate is y .

[0071] The position of the maximum curvature of the uniaxial compression curve is obtained, specifically:

[0072] The uniaxial compression curve has a starting segment OM and a terminal segment O'M'; wherein the starting segment OM and the terminal segment O'M' are both straight line types;

[0073] The starting segment OM and the ending segment O'M' are respectively extended to obtain an extension line of the starting segment OM and an extension line of the ending segment O'M'; the extension line of the starting segment OM and the extension line of the ending segment O'M' intersect at an intersection point Y';

[0074] From the intersection point Y', the angle bisector of the extension line of the starting segment OM and the extension line of the ending segment O'M' is drawn, and intersects with the uniaxial compression curve at the intersection point Y; the intersection point Y is the position of the maximum curvature of the uniaxial compression curve.

[0075] Step S4, according to the yield stress σ of each group of rockfill aggregates after undergoing a predetermined number of dry-wet cycles N obtained in step S3 y , a prediction model for the uniaxial compression porosity e of rockfill aggregates considering the influence of the number of dry-wet cycles N was constructed;

[0076] Step S4 is specifically as follows:

[0077] Step S4.1: Assume that n+1 groups of rockfill material aggregates are screened out in step S1, and the number of dry-wet cycles N for each group is N. 0 ,N 1 , N 2 ,...,N n , through uniaxial compression test, the corresponding yield stresses are: σ y0 ,σ y1 ,σ y2 ,...,σ yn ; Among them, N 0 =0, indicating that the rockfill aggregate of the corresponding group is naturally air-dried without dry-wet cycle test; N 1 , N 2 ,...,N n , are both greater than or equal to 1;

[0078] Step S4.2, the yield stress σ y0 ,σ y1 ,σ y2 ,...,σ yn , divided by σ y0 , the yield stress ratios k of each group of rockfill aggregates relative to the naturally air-dried rockfill aggregates are obtained as follows: k 0 ,k 1 ,k 2 ,...,k n ;

[0079] Step S4.3, fitting the kN variation curve of the yield stress ratio k with the number of dry-wet cycles N, thereby establishing the kN relationship equation for the relationship between the reaction yield stress ratio k and the number of dry-wet cycles N:

[0080] k=A(1-exp -BN ) C (2)

[0081] Where: A, B, C are the first model parameter, the second model parameter and the third model parameter of equation (2) respectively; e is the base of the natural logarithm function; and the yield stress ratio k can reflect the degree of degradation of the mechanical properties of reactor rock.

[0082] Step S4.4, establish the uniaxial compression porosity e of the naturally air-dried rockfill aggregate as a function of axial stress σ v The changing equation is:

[0083]

[0084] Where: e 0 , λ and D are the first model parameter, the second model parameter and the third model parameter of equation (3) respectively; p 100 The fixed value is 100kPa. ;

[0085] Step S4.5, combining equation (2) and equation (3), construct a prediction model for the uniaxial compression porosity e of the rockfill aggregate considering the influence of the number of dry-wet cycles N:

[0086]

[0087] Step S4 ends.

[0088] Step S5, using the prediction model of the uniaxial compression porosity e of the rockfill aggregate, the rockfill aggregates with the same rockfill particle size distribution characteristics are subjected to different dry-wet cycles N under different axial stresses σ v The uniaxial compression porosity e is predicted.

[0089] An embodiment is described below:

[0090] In this embodiment, the uniaxial compression porosity e of the rockfill material of a core rockfill dam is predicted by taking the rockfill material of a core rockfill dam as an example after experiencing different dry-wet cycles N under uniaxial compression.

[0091] 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;

[0092] Specifically, the particle size distribution characteristics of the rockfill material particles are in accordance with the particle size distribution characteristics of formula (1):

[0093]

[0094] Where: d is the particle size of the rockfill material in the range of 5 to 15 mm; the first model parameter P 0 , the second model parameter γ, the third model parameter ω, 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 screened rockfill material particles are divided into 5 groups of rockfill material aggregates. The particle size distribution characteristic curve of each group of rockfill material aggregates is calculated by formula (1) as follows: Figure 2 The particle size distribution characteristics of the rockfill material are as follows: the mass percentage of small-size rockfill material of 5 to 7 mm is 20%; the mass percentage of medium-size rockfill material of 7 to 12 mm is 70%; and the mass percentage of large-size rockfill material of 12 to 15 mm is 10%.

[0096] Step S2, performing a dry-wet cycle test on each group of rockfill material assemblies at different predetermined dry-wet cycle numbers N;

[0097] In this embodiment, for the five groups of rockfill material assemblies, the first group of rockfill material assemblies were naturally air-dried without undergoing the wet-dry cycle test, and therefore, the number of wet-dry cycles N thereof was 0; for the second to fourth groups of rockfill material assemblies, the wet-dry cycle test method was as follows: the time for one soaking and one air-drying was set to 24 hours, that is, the rockfill material assemblies were recorded as completing one wet-dry cycle after undergoing 24 hours of soaking and 24 hours of air-drying, and for the second to fourth groups of rockfill material assemblies, the number of wet-dry cycles N performed were 8, 16, 24, and 32, respectively, and after completing the corresponding number of wet-dry cycle tests, they were taken out from the wet-dry cycle test machine.

[0098] Step S3, performing a uniaxial compression test on each group of rockfill material assemblies that have completed a predetermined number of dry-wet cycles N, and obtaining an axial stress σ corresponding to the predetermined number of dry-wet cycles N. v With axial strain ε v Variation of uniaxial compression curves;

[0099] In this embodiment, uniaxial compression tests were performed on five groups of rockfill material assemblies with a dry-wet cycle number N of 0, 8, 16, 24, and 32, respectively, and quasi-static loading was performed using a displacement loading method until the target axial stress σ v ,get Figure 3 The axial stress-axial strain curve under different dry-wet cycle numbers N shown is the uniaxial compression curve.

[0100] By analyzing the uniaxial compression curve, the yield stress σ of the rockfill aggregate after each group of dry-wet cycles N is determined. y Specifically, the position of the maximum curvature of the uniaxial compression curve is obtained, and the axial stress σ corresponding to this position is v The yield stress σ of the rockfill aggregate is y .

[0101] The position of the maximum curvature of the uniaxial compression curve is obtained by: Figure 4 As shown, the uniaxial compression curve has a starting segment OM and a terminating segment O'M'; wherein, the starting segment OM and the terminating segment O'M' are both straight line types; the starting segment OM and the terminating segment O'M' are respectively extended to obtain the starting segment OM extension line and the terminating segment O'M' extension line; the starting segment OM extension line and the terminating segment O'M' extension line intersect at the intersection point Y'; the angle bisector of the starting segment OM extension line and the terminating segment O'M' extension line is drawn from the intersection point Y', and intersects with the uniaxial compression curve at the intersection point Y; the intersection point Y is the position of the maximum curvature of the uniaxial compression curve.

[0102] Step S4, according to the yield stress σ of each group of rockfill aggregates after undergoing a predetermined number of dry-wet cycles N obtained in step S3 y , a prediction model for the uniaxial compression porosity e of rockfill aggregates considering the influence of the number of dry-wet cycles N was constructed;

[0103] Step S4.1: for the five groups of rockfill material assemblies selected in step S1, after the number of dry-wet cycles N is 0, 8, 16, 24, and 32, the corresponding yield stresses are obtained through uniaxial compression test: σ y0 ,σ y1 ,σ y2 ,σ y3 ,σ y4 ;

[0104] Step S4.2, the yield stress σ y0 ,σ y1 ,σ y2 ,σ y3 ,σ y4 , divided by σ y0 , the yield stress ratios k of each group of rockfill aggregates relative to the naturally air-dried rockfill aggregates are obtained as follows: k 0 ,k 1 ,k 2 ,k 3 ,k 4 ; Obviously, k 0 is equal to 1;

[0105] Step S4.3, the fitting is as follows Figure 5 The kN variation curve of the yield stress ratio k and the number of dry-wet cycles N is shown, so as to establish the kN relationship equation of the reaction yield stress ratio k and the number of dry-wet cycles N:

[0106] k=A(1-exp -BN ) C (2)

[0107] Wherein: A, B, C are respectively the first model parameter, the second model parameter and the third model parameter of equation (2), and in this embodiment, they are respectively: 0.369, 0.001, -0.102; e is the base of the natural logarithm function;

[0108] Step S4.4, establish the uniaxial compression porosity e of the naturally air-dried rockfill aggregate as a function of axial stress σ v The changing equation is:

[0109]

[0110] Where: e 0, λ and D are the first model parameter, the second model parameter and the third model parameter of equation (3) respectively; p 100 is a fixed value; e can be determined by the uniaxial compression test results of naturally air-dried rockfill aggregates and the test data of their uniaxial compression porosity e. 0 , the values ​​of λ and D are 1.25, 0.18 and 661 respectively.

[0111] Step S4.5, through the test data analysis, obtain Figure 6 The uniaxial compression porosity e of the rockfill aggregate after 8, 16, 24, and 32 dry-wet cycles as a function of axial stress σ is shown in the figure. v Change curve;

[0112] right Figure 6 The change curve is analyzed and combined with equations (2) and (3), a prediction model for the uniaxial compression porosity e of rockfill aggregate considering the influence of the number of dry-wet cycles N is constructed:

[0113]

[0114] Substituting the model parameters determined in this embodiment, the prediction model of the uniaxial compression porosity e is obtained as follows:

[0115]

[0116] Step 5: Using the prediction model of formula (5), the rockfill aggregates with the same rockfill particle size distribution characteristics are subjected to different dry-wet cycles N and different axial stresses σ v The uniaxial compression porosity e is predicted.

[0117] In this embodiment, the number of dry-wet cycles N is set to 40 times, and the axial stress σ is directly predicted by formula 5. v When the pressures are 10 kPa, 100 kPa, 500 kPa, 1000 kPa, 5000 kPa and 10000 kPa, the predicted values ​​of the uniaxial compression porosity e are 0.905, 0.863, 0.747, 0.663, 0.414 and 0.295 respectively.

[0118] As a verification, a rockfill aggregate with the same particle size distribution characteristics was subjected to 40 dry-wet cycles and then to a uniaxial compression test. Figure 7 The uniaxial compression porosity e of the rockfill aggregate after 40 dry-wet cycles as a function of axial stress σ is shown in the figure. v The change relationship diagram. Figure 7 It can be obtained that under the axial stress σ vWhen the pressure is 10 kPa, 100 kPa, 500 kPa, 1000 kPa, 5000 kPa and 10000 kPa, the uniaxial compression porosity e of the rockfill aggregate is 0.896, 0.871, 0.782, 0.690, 0.433 and 0.308 respectively.

[0119] like Figure 8 The figure shows the rockfill aggregate after 40 dry-wet cycles at different axial stresses σ v Comparison chart of the predicted value of the uniaxial compression porosity e and the experimental measured data. Figure 8 It can be seen that the error between the prediction results of the present invention and the experimental measured data results is less than 5%, which meets the prediction accuracy requirements of the model.

[0120] The present invention also provides a system for realizing a method for predicting the uniaxial compression porosity of a rockfill aggregate considering the influence of dry-wet cycles, which is used to automatically realize the method for predicting the uniaxial compression porosity of a rockfill aggregate considering the influence of dry-wet cycles provided by the present invention, comprising:

[0121] The test preparation module is used to execute the contents described in step S1 above, and is used to screen the rockfill material particles to select multiple groups of rockfill material assemblies that meet the particle size distribution characteristics of the rockfill material particles for subsequent tests;

[0122] A dry-wet cycle test device, used to perform the contents described in step S2 above, and to perform dry-wet cycle tests on each group of rockfill material assemblies at different predetermined dry-wet cycle numbers N;

[0123] The uniaxial compression test device is used to perform the content described in step S3 above, and is used to perform a uniaxial compression test on each group of the rockfill material aggregates that have completed the predetermined number of dry-wet cycles N, and obtain the axial stress σ corresponding to the predetermined number of dry-wet cycles N. v With axial strain ε v The yield stress σ of the rockfill aggregate after each group of dry-wet cycles N is determined by analyzing the uniaxial compression curve. y ;

[0124] The prediction model building module is used to execute the content described in step S4 above, and is used to obtain the yield stress σ of the rockfill material aggregate after each group of predetermined dry-wet cycles N. y , a prediction model for the uniaxial compression porosity e of rockfill aggregates considering the influence of the number of dry-wet cycles N was constructed;

[0125] The uniaxial compression porosity prediction module is used to execute the content described in step S5 above, and is used to use the prediction model of the uniaxial compression porosity e of the rockfill aggregate to predict the porosity of the rockfill aggregate with the same rockfill aggregate particle size distribution characteristics after experiencing different dry-wet cycles N under different axial stresses σ v The uniaxial compression porosity e is predicted.

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

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

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

[0129] The present invention relates to a prediction method and system for the uniaxial compression porosity of a rockfill aggregate considering the influence of dry-wet cycles, and proposes a prediction model for the uniaxial compression porosity of a rockfill aggregate considering different dry-wet cycles. The data obtained from the experiment are brought into the model to determine the parameters, and the final prediction model can be obtained. The prediction model can be used to predict the uniaxial compression porosity of the rockfill aggregate under any dry-wet cycle number, and provide accurate and reliable data for the deformation of the actual rockfill dam project during operation due to the cyclic change of the reservoir water level. For example, it is used to determine the uniaxial compression porosity and deformation of the rockfill material for the core wall rockfill dam after experiencing the dry-wet cycle caused by the cyclic rise and fall of the reservoir water level.

[0130] Moreover, the present invention only needs to perform dry-wet cycle treatments for different times on 4 to 5 groups of rockfill material assemblies with the same particle size distribution, and perform uniaxial compression tests on the rockfill material particles after the dry-wet cycles to determine the model parameters. The present invention has low requirements on test equipment, a small number of tests, and simple operation. It can effectively save test materials and test time, and improve work efficiency.

[0131] The solution of the present invention is particularly suitable for the design stage of rockfill dam engineering.

[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 perform a dry-wet cycle test and a uniaxial compression test on the rockfill material assembly to obtain a prediction model for the uniaxial compression porosity e of the rockfill material assembly that takes into account the influence of the dry-wet cycle number N; the obtained prediction model is used to predict the porosity e of the rockfill material assembly under different axial stresses σ after different dry-wet cycles. v The uniaxial compression porosity e of the rockfill material under the condition of uniaxial compression is used to determine whether the uniaxial compression porosity e of the rockfill material meets the design requirements of the rockfill dam project; if so, it can be recommended to use the rockfill material that meets the particle distribution characteristics of the rockfill material for dam construction. If not, the specific data of the rockfill material particle distribution characteristics of the rockfill material assembly is replaced, and the prediction of the uniaxial compression porosity e is repeated until the rockfill material assembly with the uniaxial compression porosity e meets the design requirements of the rockfill dam project, and the dam construction is guided. Therefore, the scheme provided by the present invention can provide reference data for the selection of rockfill material assemblies in the design stage of the rockfill dam project, and guide the screening of rockfill material particles used for dam construction.

[0133] In summary, the present invention can achieve accuracy and high efficiency in predicting the uniaxial compression porosity ratio 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 method for predicting the uniaxial compression porosity of rockfill aggregates considering the influence of dry-wet cycles, characterized in that: The steps include: 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; Step S2, performing a dry-wet cycle test on each group of rockfill material assemblies at different predetermined dry-wet cycle numbers N; Step S3, performing a uniaxial compression test on each group of rockfill material assemblies that have completed a predetermined number of dry-wet cycles N, and obtaining an axial stress σ corresponding to the predetermined number of dry-wet cycles N. v With axial strain ε v The yield stress σ of the rockfill aggregate after each group of dry-wet cycles N is determined by analyzing the uniaxial compression curve. y ; Step S4, according to the yield stress σ of each group of rockfill aggregates after undergoing a predetermined number of dry-wet cycles N obtained in step S3 y , a prediction model for the uniaxial compression porosity e of rockfill aggregates considering the influence of the number of dry-wet cycles N was constructed; Step S5, using the prediction model of the uniaxial compression porosity e of the rockfill aggregate, the rockfill aggregates with the same rockfill particle size distribution characteristics are subjected to different dry-wet cycles N under different axial stresses σ v The uniaxial compression porosity e is predicted.

2. The method for predicting the uniaxial compression porosity of rockfill aggregates considering the influence of dry-wet cycles according to claim 1, characterized in that: In step S1, the particle size distribution characteristics of the rockfill material particles are in accordance with the particle size distribution characteristics of formula (1): Where: d is the particle size of the rockfill material in the set particle size range; Γ is the gamma function; P0, γ, ω, 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; and P is the mass percentage of the corresponding rockfill material particle size d in the rockfill material aggregate.

3. The method for predicting the uniaxial compression porosity of rockfill aggregates considering the influence of dry-wet cycles according to claim 2, characterized in that: The particle size range is set to 5-15 mm; the first model parameter P0, the second model parameter γ, the third model parameter ω, and 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 method for predicting the uniaxial compression porosity of rockfill aggregates considering the influence of dry-wet cycles according to claim 1, characterized in that: The screened rockfill material particles are divided into 4 to 5 groups of rockfill material assemblies.

5. The method for predicting the uniaxial compression porosity of rockfill aggregates considering the influence of dry-wet cycles according to claim 1, characterized in that: The particle size distribution characteristics of the rockfill material are as follows: the mass percentage of small-size rockfill material of 5-7 mm is 20%; the mass percentage of medium-size rockfill material of 7-12 mm is 70%; and the mass percentage of large-size rockfill material of 12-15 mm is 10%.

6. The method for predicting the uniaxial compression porosity of rockfill aggregates considering the influence of dry-wet cycles according to claim 1, characterized in that: In step S3, a uniaxial compression test is performed on each group of the rockfill material assemblies that have completed a predetermined number of dry-wet cycles N, specifically: Each group of the rockfill material aggregates that completed the predetermined number of dry-wet cycles N was divided into 10 parts, and then filled into the container of the uniaxial compression test in 10 layers. After each layer was filled, the surface of each layer of rockfill material was knocked with a rubber mallet to make the surface of each layer of rockfill material flat and reach the corresponding scale line of the container, ensuring that the dry density of each layer of rockfill material was between 0.88 and 0.89, and then the uniaxial compression test was carried out.

7. The method for predicting the uniaxial compression porosity of rockfill aggregates considering the influence of dry-wet cycles according to claim 1, characterized in that: In step S3, the yield stress σ of the rockfill aggregate after each group of dry-wet cycles N is determined by analyzing the uniaxial compression curve. y Specifically: Find the position of the maximum curvature of the uniaxial compression curve, and the axial stress σ corresponding to this position is v The yield stress σ of the rockfill aggregate is y .

8. The method for predicting the uniaxial compression porosity of rockfill aggregates considering the influence of dry-wet cycles according to claim 7, characterized in that: The position of the maximum curvature of the uniaxial compression curve is obtained, specifically: The uniaxial compression curve has a starting segment OM and a terminal segment O'M'; wherein the starting segment OM and the terminal segment O'M' are both straight line types; The starting segment OM and the ending segment O'M' are respectively extended to obtain an extension line of the starting segment OM and an extension line of the ending segment O'M'; the extension line of the starting segment OM and the extension line of the ending segment O'M' intersect at an intersection point Y'; From the intersection point Y', the angle bisector of the extension line of the starting segment OM and the extension line of the ending segment O'M' is drawn, and intersects with the uniaxial compression curve at the intersection point Y; the intersection point Y is the position of the maximum curvature of the uniaxial compression curve.

9. The method for predicting the uniaxial compression porosity of rockfill aggregates considering the influence of dry-wet cycles according to claim 1, characterized in that: Step S4 is specifically as follows: Step S4.1: Assume that n+1 groups of rockfill material aggregates are screened out in step S1, and the number of dry-wet cycles N performed respectively is N0, N1, N2, ..., N n , through uniaxial compression test, the corresponding yield stresses are: σ y0 ,σ y1 ,σ y2 ,...,σ yn ; Wherein, N0=0, which means that the rockfill aggregate of the corresponding group is naturally air-dried without dry-wet cycle test; N1, N2,..., N n , are greater than or equal to 1; Step S4.2, the yield stress σ y0 ,σ y1 ,σ y2 ,...,σ yn , divided by σ y0 The yield stress ratios k of each group of rockfill aggregates relative to the naturally air-dried rockfill aggregates are obtained as follows: k0, k1, k2, ..., k n ; Step S4.3, fitting to obtain the kN variation curve of the yield stress ratio k with the number of dry-wet cycles N, thereby establishing the kN relationship equation for the relationship between the reaction yield stress ratio k and the number of dry-wet cycles N: k=A(1-exp -BN ) C (2) Where: A, B, C are the first model parameter, the second model parameter and the third model parameter of equation (2) respectively; e is the base of the natural logarithm function; Step S4.4, establish the uniaxial compression porosity e of the naturally air-dried rockfill aggregate as a function of axial stress σ v The changing equation is: Where: e0, λ and D are the first model parameter, the second model parameter and the third model parameter of equation (3) respectively; p 100 is a fixed value; Step S4.5, combining equation (2) and equation (3), construct a prediction model for the uniaxial compression porosity e of the rockfill aggregate considering the influence of the number of dry-wet cycles N: Step S4 ends.

10. A system for implementing the method for predicting the uniaxial compression porosity of rockfill aggregates considering the influence of dry-wet cycles as claimed in any one of claims 1 to 9, characterized in that: include: The test preparation module is used to screen the rockfill material particles and select multiple groups of rockfill material aggregates that meet the particle size distribution characteristics of the rockfill material for subsequent tests; A dry-wet cycle test device, used to perform dry-wet cycle tests on each group of rockfill material assemblies at different predetermined dry-wet cycle numbers N; The uniaxial compression test device is used to perform a uniaxial compression test on each group of rockfill material aggregates that have completed a predetermined number of dry-wet cycles N, and obtain the axial stress σ corresponding to the predetermined number of dry-wet cycles N. v With axial strain ε v The yield stress σ of the rockfill aggregate after each group of dry-wet cycles N is determined by analyzing the uniaxial compression curve. y ; The prediction model building module is used to obtain the yield stress σ of the rockfill aggregate after each group of predetermined dry-wet cycles N. y , a prediction model for the uniaxial compression porosity e of rockfill aggregates considering the influence of the number of dry-wet cycles N was constructed; The uniaxial compression porosity prediction module is used to use the prediction model of the uniaxial compression porosity e of the rockfill aggregate to predict the porosity of the rockfill aggregate with the same rockfill particle size distribution characteristics under different axial stresses σ after experiencing different dry-wet cycles N. v The uniaxial compression porosity e is predicted.

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