Method for estimating strength ratio of rocks, device for analyzing deformation of natural ground, and method and program for analyzing deformation of natural ground

Abstract

To provide a method for estimating a strength ratio of rocks, capable of accurately estimating the decrease in strength of rocks.SOLUTION: In a first test step, the strength of a first specimen, which is a rock specimen, is determined. In a second test step, the specimen is dried to prepare a second specimen, and a saturation degree of the second specimen is determined. In a third test step, the specimen is dried in the same way as the second specimen, and then is submerged in water to prepare a third specimen, and a strength ratio of the third specimen is determined. In a strength degradation model creation step, a strength ratio of the second specimen is assumed to be 1, and a saturation degree of the third specimen is assumed to be 1. Then, a strength degradation model showing a relation of a change in a saturation degree due to drying and submersion of rocks with a strength ratio of the rocks is created based on the saturation degrees and the strength ratios of the second specimen and the third specimen. In a strength ratio estimation step, the change in the saturation degree due to drying and submersion of the rocks is input into the strength degradation model to estimate the strength ratio of the rocks.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for estimating the strength ratio of rocks, an apparatus for analyzing natural ground deformation, and a method and program for analyzing natural ground deformation. [Background technology]

[0002] When examining countermeasures against deformation of mountain tunnels using a numerical analysis model, it is necessary to express the deformation of the ground around the tunnel. Non-Patent Documents 1 and 2 propose analytical methods for expressing deformation of ground by reducing the strength of the ground. Non-Patent Document 3 proposes a method for performing deformation analysis by setting the strength of the ground material according to the degree of saturation obtained by a seepage flow analysis. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Tsuyoshi Matsunaga, Hiroo Kumasaka, Yoshiyuki Kojima, Toshihiro Asakura: Study on prediction and countermeasures for tunnel deformation considering time-dependent deterioration of rock mass strength, Journal of Japan Society of Civil Engineers, No. 799, III-72, pp. 75-88, 2005 [Non-Patent Document 2] Keisuke Shimamoto, Kazue Nojo, Yoshiyuki Kojima, Kazuhiko Tsukada, Toshihiro Asakura: Study on roadbed uplift phenomenon and its countermeasures in mountain tunnels considering the impact during construction, Journal of Japan Society of Civil Engineers, Vol. 69, No. 2, pp. 105-120, 2013 [Non-Patent Document 3] Yoshiya Hata and Koji Ichii: Dynamic analysis of embankment slopes considering the effects of rainfall, Journal of the Japanese Landslide Society, Vol. 48, No. 4, pp. 187-197, 2011 [Non-Patent Document 4] Keisuke Shimamoto, Takeshi Kawagoe, Kazue Noshiro, Hiroaki Kobayashi, Atsumi Isotani: Estimation of tunnel swelling mechanism focusing on water content change, Journal of Japan Society of Civil Engineers, Proceedings of the Society of Civil Engineers, Vol. 76, No. 1, pp. 34-48, 2020 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the models of natural ground strength reduction in Non-Patent Document 1 and Non-Patent Document 2 have not been fully verified by rock tests, etc. The method in Non-Patent Document 3 only considers the reduction in strength associated with an increase in the degree of saturation. Therefore, there are issues regarding their validity.

[0005] The problem that the present invention aims to solve is to provide a rock strength ratio estimation method, a ground deformation analysis device, a ground deformation analysis method, and a program that can accurately estimate rock strength reduction and ground deformation. [Means for solving the problem]

[0006] The method for estimating the strength ratio of rock of the present invention includes a first test step, a second test step, a third test step, a strength reduction model creation step, and a strength ratio estimation step. In the first test step, the strength of a first specimen, which is a rock specimen, is determined. In the second test step, the specimen is dried to create a second specimen, and the degree of saturation of the first specimen is assumed to be 1 to determine the degree of saturation of the second specimen. In the third test step, the specimen is dried in the same manner as the second specimen and then submerged in water to create a third specimen, and the strength of the third specimen is determined, and the strength ratio of the third specimen to the strength of the first specimen is determined. In the strength reduction model creation step, the strength ratio of the second specimen to the strength of the first specimen is assumed to be 1, and the degree of saturation of the third specimen is assumed to be 1. Then, a strength reduction model is created based on the degrees of saturation and strength ratios of the second and third specimens, which shows the relationship between the change in the degree of saturation of the rock due to drying and submersion in water and the strength ratio of the rock to the strength of the first specimen. In the strength ratio estimation process, the change in saturation degree due to drying and water infiltration of rocks is input into a strength degradation model to estimate the strength ratio of rocks.

[0007] By creating a strength degradation model based on rock tests, the strength degradation of rocks can be estimated with high accuracy. In addition, a strength degradation model is created that shows the relationship between the change in saturation degree due to drying and water immersion of rocks and the strength ratio of rocks. This allows the strength degradation of rocks with slaking properties to be estimated with high accuracy.

[0008] In the second test process, the test specimen is dried to multiple dryness levels to create multiple types of second test specimens, and the saturation levels of the multiple types of second test specimens are determined. In the third test process, the test specimen is dried in the same manner as the multiple types of second test specimens, and then submerged in water to create multiple types of third test specimens, and the strength ratios of the multiple types of third test specimens are determined. In the strength degradation model creation process, a strength degradation model is created by linearly interpolating between the strength ratios of the first test specimen and the multiple types of third test specimens, and linearly interpolating between the strength ratios of the second test specimen and the third test specimen that have experienced similar drying.

[0009] By linearly interpolating between the strength ratios of the first specimen and the multiple types of third specimens, the strength reduction of the rock can be estimated according to the degree of saturation after any drying. By linearly interpolating between the strength ratios of the second and third specimens that have experienced similar drying, the strength reduction of the rock can be estimated according to the degree of saturation after any water immersion.

[0010] The natural ground deformation analysis device of the present invention has an analytical model creation unit, a seepage flow analysis unit, a strength ratio estimation unit, and a deformation analysis unit. The analytical model creation unit creates an analytical model of the natural ground. The seepage flow analysis unit performs a seepage flow analysis of the analytical model to determine changes in saturation of elements of the analytical model due to drying and flooding. The strength ratio estimation unit inputs the changes in saturation of the elements of the analytical model to a strength reduction model in the aforementioned method for estimating strength ratios of rocks, and estimates the strength ratios of the elements of the analytical model. The deformation analysis unit performs deformation analysis of the analytical model using the strength ratios of the elements of the analytical model.

[0011] The analysis model creation unit, the seepage flow analysis unit, and the strength ratio estimation unit can estimate the strength distribution based on the change in the saturation degree of the natural ground. The deformation analysis unit can accurately estimate the deformation of the natural ground due to groundwater flow, etc.

[0012] The deformation analysis unit uses the strength ratio of the elements of the analytical model to determine the adhesive force of the elements of the analytical model, and performs deformation analysis of the analytical model. This allows the deformation of the ground to be estimated with high accuracy.

[0013] In the method for analyzing natural ground deformation of the present invention, a computer of an apparatus for analyzing natural ground deformation executes an analytical model creation step, a seepage flow analysis step, a strength ratio estimation step, and a deformation analysis step. The program of the present invention causes a computer of a natural ground deformation analysis device to execute an analytical model creation step, a seepage flow analysis step, a strength ratio estimation step, and a deformation analysis step. In the analytical model creation process, an analytical model of the natural ground is created. In the seepage analysis process, a seepage analysis of the analytical model is performed to determine changes in the degree of saturation of the elements of the analytical model due to drying and flooding. In the strength ratio estimation process, the changes in the degree of saturation of the elements of the analytical model are input into a strength reduction model in the aforementioned method for estimating the strength ratio of rock to estimate the strength ratio of the elements of the analytical model. In the deformation analysis process, deformation analysis of the analytical model is performed using the strength ratios of the elements of the analytical model.

[0014] The analysis model creation step, the seepage flow analysis step, and the strength ratio estimation step allow for estimation of strength distribution based on changes in the degree of saturation of the natural ground. The deformation analysis step using the estimated strength distribution allows for accurate estimation of deformation of the natural ground due to groundwater flow, etc. Effect of the Invention

[0015] According to the method for estimating the strength ratio of rocks of the present invention, the decrease in strength of rocks can be estimated with high accuracy. The ground deformation analysis device, the ground deformation analysis method, and the program of the present invention make it possible to estimate ground deformation with high accuracy. [Brief description of the drawings]

[0016] [Figure 1] A graph showing the relationship between air drying time and unconfined compressive strength. [Diagram 2] Graph showing the relationship between the degree of saturation of a test specimen after drying and the strength ratio after immersion in water. [Diagram 3] Graph of rock strength degradation model. [Figure 4] Block diagram of the rock deformation analysis device. [Diagram 5] 1 is a flowchart of a method for analyzing deformation of natural ground. [Figure 6] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, a rock strength ratio estimation method, a natural ground deformation analysis device, a natural ground deformation analysis method, and a program according to embodiments will be described with reference to the drawings. Some rocks become fragmented when they are submerged in water after drying. This phenomenon is called slaking. It is known that Neogene muddy soft rocks are particularly susceptible to slaking. Non-Patent Document 4 proposes a mechanism in which the rocks that make up the ground lose strength due to slaking, causing deformation of the ground.

[0018] In the embodiment, rock testing is performed on rocks that make up the natural ground. Below, as an example of rock test results (referred to as a test example), test results for rocks taken from a Neogene mudstone natural ground are shown. Based on the results of the rock testing, a strength degradation model of the target rock is created. Next, a numerical analysis is performed using an analytical model that simulates the target natural ground. The numerical analysis consists of a seepage analysis and a deformation analysis. Some of the physical property values ​​used in the deformation analysis are determined from the output results of the seepage analysis and the strength degradation model. This series of numerical analyses is loaded into a computer with a monitor or the like as a numerical analysis program that can be executed by a computer, and functions under the control of the computer.

[0019] (Rock testing, rock strength degradation model) Rock specimens are prepared to conduct rock tests. Rocks are collected from the natural ground that is the subject of deformation analysis. Rocks that have a natural water content and are nearly saturated are collected. By collecting rocks from a position lower than the groundwater table, rocks that are nearly saturated can be collected. Cylindrical specimens are prepared from the collected rocks.

[0020] The first test is carried out on the first specimen to determine its unconfined compressive strength (sometimes simply called strength) (first test process). In measuring the unconfined compressive strength, a compressive load is applied to the axial end face of the specimen using a compression testing machine. The unconfined compressive strength is calculated by dividing the maximum load applied until the specimen breaks by the area of ​​the end face of the specimen. Figure 1 is a graph showing the relationship between air drying time and unconfined compressive strength. The first specimen is a specimen with natural water content and no water infiltration. In the test example, the unconfined compressive strength of the first specimen is 4.8 MPa.

[0021] The moisture content of the first specimen is determined. The moisture content is the mass of water contained in the specimen divided by the mass of the rock in the specimen. The mass of water contained in the specimen is the total mass of the specimen minus the mass of the rock in the specimen. The mass of the rock in the specimen is the mass of the specimen when it is almost completely dried (bone-dried). The total mass and the bone-dried mass of the first specimen after the uniaxial compressive strength measurement are measured. The total mass and the bone-dried mass of the specimen may be measured using a first specimen different from the first specimen after the uniaxial compressive strength measurement.

[0022] The test specimen is dried to create a second test specimen. For example, the test specimen is kept in a specified temperature and humidity environment for a specified time to dry (air-dry) the test specimen. The test specimen is dried to multiple levels of dryness to create multiple types of second test specimens. In the test example shown in Figure 1, the test specimen is dried to three levels of dryness to create three types of second test specimens. The three levels of dryness are air-drying for 8 hours, air-drying for 72 hours, and bone dry.

[0023] The unconfined compressive strength of the three types of second specimens is obtained. In the test example shown in Figure 1, the second specimen is not submerged in water. The unconfined compressive strength of the second specimen is 5.7 MPa when air-dried for 8 hours, 10.5 MPa when air-dried for 72 hours, and 13.1 MPa when completely dried.

[0024] A second test is carried out to determine the moisture content of the second specimen (second test step). The moisture content is measured using the second specimen after the unconfined compressive strength measurement. The moisture content may be measured using a second specimen other than the second specimen after the unconfined compressive strength measurement. The moisture content of the second specimen is normalized by dividing it by the moisture content of the first specimen. As described above, the first specimen is almost saturated, so the degree of saturation of the first specimen is assumed to be 1. At this time, the normalized moisture content of the second specimen can be regarded as the degree of saturation. Therefore, the moisture content of the second specimen is normalized by the moisture content of the first specimen to determine the degree of saturation of the second specimen.

[0025] The specimen is dried in the same way as the second specimen, and then submerged in water to create the third specimen. When submerging the specimen, it is kept in water for a long time until there is almost no change in mass of the specimen. The degree of saturation of the third specimen after submersion can be considered to be 1. The specimen is dried in the same way as the multiple types of second specimens, and then submerged in water to create multiple types of third specimens. In the test example shown in Figure 1, the specimen is dried to three different degrees of dryness and then submerged in water to create three types of third specimens. The degree of saturation of the three types of third specimens after drying (before submersion) can be considered to be the same as the degree of saturation of the three types of second specimens.

[0026] A third test is conducted to determine the unconfined compressive strength of the third specimen (third test step). In the test example shown in Figure 1, the third specimen is submerged in water. The unconfined compressive strength of the third specimen is 0.7 MPa when it is submerged in water after being air-dried for 8 hours. The unconfined compressive strength is 0.0 MPa when it is submerged in water after being air-dried for 72 hours and when it is completely dried and then submerged in water.

[0027] The strength ratio of the third specimen to the strength of the first specimen is calculated. The strength ratio of the third specimen is the unconfined compressive strength of the third specimen after submersion divided by the unconfined compressive strength of the first specimen before submersion. As mentioned above, the unconfined compressive strength of the first specimen in the test example before submersion is 4.8 MPa. The strength ratio of the third specimen after submersion is 0.15 when air-dried for 8 hours, and 0.0 when air-dried for 72 hours and when completely dried.

[0028] For comparison, the unconfined compressive strength of the first specimen after submersion is obtained. The first specimen was not dried and remained at its natural water content, so this corresponds to the case where the specimen was air-dried for 0 hours. In the test example shown in Figure 1, the first specimen after submersion is the case where the specimen is submerged at its natural water content. In the test example, the unconfined compressive strength of the first specimen after submersion is 5.8 MPa. Since the unconfined compressive strength of the first specimen after submersion is equivalent to the unconfined compressive strength before submersion, the strength ratio of the first specimen after submersion is assumed to be 1.

[0029] Figure 2 is a graph showing the relationship between the degree of saturation of the specimens after drying and the strength ratio after drying and immersion in water. The first specimen corresponds to a specimen that has been air-dried for 0 hours from a saturated state, so its degree of saturation after drying is 1. The degree of saturation of the third specimen after drying (before immersion in water) is 0.8 when air-dried for 8 hours, 0.4 when air-dried for 72 hours, and 0.0 when completely dried.

[0030] The degree of saturation of the specimen after drying is w, and the strength ratio after drying and immersion is q * As shown in Figure 2, (w, q * ) is assumed to change linearly. In other words, linear interpolation is performed between the strength ratios of the first specimen and the multiple types of third specimens. This results in q * is a function of w * This can be organized as (w).

[0031] Incidentally, Figure 1 shows that the unconfined compressive strength increases as the specimen dries. However, the decrease in unconfined compressive strength due to water infiltration after drying is more significant. Therefore, we assume that the unconfined compressive strength of the specimen after drying is equal to the unconfined compressive strength of the specimen before drying (i.e., the first specimen, which has the natural water content). In other words, we assume that the strength ratio of the second specimen after drying is 1.

[0032] As described above, the following assumptions (1) to (3) are made regarding the results of the test example obtained. (1) The degree of saturation of the specimen before drying (specimen 1) is 1. (2) The unconfined compressive strength of the specimen after drying is equal to the unconfined compressive strength of the specimen at its natural moisture content. (3) The degree of saturation of the specimen (the third specimen after submersion) at the time of the uniaxial compression test was 1.

[0033] By assuming (1), w can be regarded as the degree of saturation after drying (0≦w≦1). Furthermore, by assuming (3) above, q * (w) can be regarded as the strength ratio to the initial unconfined compressive strength when the degree of saturation of the specimen changes from 1 to w to 1.

[0034] Furthermore, assume (4) below. (4) During the process of water immersion after drying, the unconfined compressive strength decreases in proportion to the degree of saturation until the degree of saturation reaches 1. As mentioned above, the degree of saturation of the second specimen after drying is less than 1, and the strength ratio is 1. On the other hand, the degree of saturation of the third specimen after immersion is 1, and the strength ratio is less than 1. During the immersion process of the third specimen, the degree of saturation increases from less than 1 to 1. During this time, it is assumed that the strength ratio of the third specimen decreases linearly from 1 to less than 1. In other words, linearly interpolate between the strength ratios of the second and third specimens that have experienced similar drying.

[0035] Here, let Q(w,w') denote the strength ratio to the initial unconfined compressive strength when a rock that was initially saturated dries to an arbitrary degree of saturation w, and then recovers to an arbitrary degree of saturation w' (w≦w'≦1) through submersion. Then, by assuming all of the above (1) to (4), the following relationship holds:

[0036]

number

[0037] By expanding equation 1, Q(w,w´) can be expressed as equation 2 below.

[0038]

number

[0039] Equation 2 is a model equation that can estimate the degree of strength reduction of rock for any change in saturation degree during drying and subsequent flooding. This strength reduction model shows the relationship between the minimum saturation degree of rock during drying, the maximum saturation degree of rock during flooding after drying, and the strength ratio of the rock.

[0040] Figure 3 is a graph of a model for the reduction in strength of rock. The horizontal axis of Figure 3 is the degree of saturation after drying, w, and the vertical axis is the degree of saturation when submerged in water after drying, w'. In Figure 3, the shade of the shading indicates the magnitude of the strength ratio Q(w,w'). The point (w,w') = (1,1) in the upper left of Figure 3 is the initial state of the rock (natural water content state), where the strength ratio Q is 1. For example, if the degree of saturation w of a rock after drying is 0.5, and the degree of saturation w' when submerged in water after drying is 0.85, it can be seen that the strength ratio Q will decrease to approximately 0.4.

[0041] (Numerical Analysis) Using this strength reduction model, a numerical analysis program consisting of a seepage flow analysis process and a deformation analysis process is executed on a computer to determine the displacement of the ground whose strength has decreased in response to changes in the degree of saturation.

[0042] 4 is a block diagram of the natural ground deformation analysis device 1. The natural ground deformation analysis device 1 has an analytical model creation unit 10, a seepage flow analysis unit 20, a strength ratio estimation unit 30, a deformation analysis unit 40, and a storage unit 50.

[0043] Among the components of the natural ground deformation analysis device 1, the components other than the storage unit 50 are realized by, for example, a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Some or all of the functions of these components may be realized by hardware (including circuitry) such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a GPU (Graphics Processing Unit), or may be realized by cooperation between software and hardware. Some or all of the functions of these components may be realized by a dedicated LSI. The program may be stored in advance in a storage device (storage device having a non-transient storage medium) such as an HDD (Hard Disk Drive) or a flash memory provided in the deformation analysis device 1, or may be stored in a removable storage medium (non-transient storage medium) such as a DVD or CD-ROM, and the storage medium may be installed in the storage device provided in the deformation analysis device 1 by mounting the storage medium in a drive device provided in the deformation analysis device 1. The deformation analysis device 1 may be realized in, for example, a computer device such as a personal computer or a storage device.

[0044] 5 is a flowchart of the natural ground deformation analysis method. In the natural ground deformation analysis method, a computer of the natural ground deformation analysis device 1 executes an analytical model creation step S10, a seepage flow analysis step S20, a strength ratio estimation step S30, and a deformation analysis step S40. The program causes the computer of the natural ground deformation analysis device 1 to execute the analytical model creation step S10, the seepage flow analysis step S20, the strength ratio estimation step S30, and the deformation analysis step S40.

[0045] FIG. 6 is an explanatory diagram of the analysis model. First, the analytical model creation unit 10 creates an analytical model of the natural ground (analysis model creation step S10). Specifically, an analytical model is created by simulating the target natural ground and dividing the analysis domain into a large number of elements. The analytical model creation unit 10 requests the operator to input information required for creating the analytical model. The analytical model creation unit 10 creates the analytical model according to the information input by the operator.

[0046] Next, the seepage analysis unit 20 performs a seepage analysis (seepage analysis step S20). In the seepage analysis step, a saturated / unsaturated analysis is used to determine the change in the degree of saturation during the process in which the target rock mass reabsorbs water after drying. First, conditions such as physical properties, unsaturated characteristics, and analysis conditions are set for the analysis model (S22). The physical properties and unsaturated characteristics are set according to the type of rock. The physical properties include the saturated hydraulic conductivity, specific storage coefficient, and porosity. The unsaturated characteristics include the relationship between the relative hydraulic conductivity and the negative pressure head with respect to the degree of saturation. The analysis conditions include initial conditions and boundary conditions. Then, the analysis is performed (S24), and the results are output (S26). As a result of the analysis, the degree of saturation w that has decreased the most due to drying for each element i of the analysis model (see FIG. 6) is calculated. i and the degree of saturation w´ that increased most due to subsequent reabsorption i Output the following.

[0047] Next, the strength ratio estimation unit 30 estimates the strength ratio of each element i (strength ratio estimation step S30). The storage unit 50 of the natural ground deformation analysis device 1 shown in FIG. 4 stores the strength degradation model of rocks described above. The strength ratio estimation unit 30 requests the operator to input information on the type of rock. The strength ratio estimation unit 30 reads out the strength degradation model corresponding to the input rock type from the storage unit 50. The strength ratio estimation unit 30 estimates the strength ratio of each element i outputted by the seepage flow analysis based on the change in saturation degree (w i ,w´ i ) is input to the strength degradation model. This gives the strength ratio Q i (w i ,w´ i ) is estimated.

[0048] Next, the deformation analysis unit 40 performs deformation analysis of the natural ground using the finite difference method or the like (deformation analysis step S40). First, conditions such as physical property values ​​and analysis conditions are set (S42). Physical property values ​​are set according to the type of rock. The physical property values ​​include unit volume weight, elastic modulus, Poisson's ratio, cohesion, internal friction angle, dilatancy angle, etc. Analysis is performed under these conditions, and the amount of displacement of each element in a balanced state is obtained. Here, the cohesion c of the natural ground in a separately set natural water content state is 0 and the strength ratio Q obtained based on the results of the seepage flow analysis i The product of these two gives the adhesive force c of each element i that decreases with the change in saturation. i The adhesive strength c is calculated. i is input as the physical property value of each element i in the deformation analysis. Then, the analysis is executed again (S44) and the results are output (S46). The displacement amount of the nodes of each element in the balanced state is output as the analysis result. This makes it possible to analytically obtain the displacement of the natural ground whose strength has decreased due to a change in the degree of saturation.

[0049] As described above in detail, the rock strength ratio estimation method of the embodiment includes a first test step, a second test step, a third test step, a strength degradation model creation step, and a strength ratio estimation step. In the first test step, the strength of a first specimen, which is a rock specimen, is determined. In the second test step, the specimen is dried to create a second specimen, and the degree of saturation of the first specimen is assumed to be 1 to determine the degree of saturation of the second specimen. In the third test step, the specimen is dried in the same manner as the second specimen and then submerged in water to create a third specimen, and the strength of the third specimen is determined, and the strength ratio of the third specimen to the strength of the first specimen is determined. In the strength degradation model creation step, the strength ratio of the second specimen to the strength of the first specimen is assumed to be 1, and the degree of saturation of the third specimen is assumed to be 1. Then, a strength degradation model is created based on the degree of saturation and strength ratio of the second and third specimens, which indicates the relationship between the change in degree of saturation due to drying and water inundation of the rock and the strength ratio of the rock relative to the strength of the first specimen. In the strength ratio estimation step, the change in degree of saturation due to drying and water inundation of the rock is input into the strength degradation model to estimate the strength ratio of the rock.

[0050] By creating a strength degradation model based on rock tests, the strength degradation of rocks can be estimated with high accuracy. In addition, a strength degradation model is created that shows the relationship between the change in saturation degree due to drying and water immersion of rocks and the strength ratio of rocks. This allows the strength degradation of rocks with slaking properties to be estimated with high accuracy.

[0051] In the second test process, the test specimen is dried to multiple dryness levels to create multiple types of second test specimens, and the saturation levels of the multiple types of second test specimens are determined. In the third test process, the test specimen is dried in the same manner as the multiple types of second test specimens, and then submerged in water to create multiple types of third test specimens, and the strength ratios of the multiple types of third test specimens are determined. In the strength degradation model creation process, a strength degradation model is created by linearly interpolating between the strength ratios of the first test specimen and the multiple types of third test specimens, and linearly interpolating between the strength ratios of the second test specimen and the third test specimen that have experienced similar drying.

[0052] By linearly interpolating between the strength ratios of the first specimen and the multiple types of third specimens, the strength reduction of the rock can be estimated according to the degree of saturation after any drying. By linearly interpolating between the strength ratios of the second and third specimens that have experienced similar drying, the strength reduction of the rock can be estimated according to the degree of saturation after any water immersion.

[0053] The natural ground deformation analysis device 1 of the embodiment includes an analysis model creation unit 10, a seepage flow analysis unit 20, a strength ratio estimation unit 30, and a deformation analysis unit 40. In the method for analyzing natural ground deformation of the embodiment, a computer of an apparatus 1 for analyzing natural ground deformation executes an analytical model creation step, a seepage flow analysis step, a strength ratio estimation step, and a deformation analysis step. The program of the embodiment causes the computer of the natural ground deformation analysis device 1 to execute an analysis model creation step, a seepage flow analysis step, a strength ratio estimation step, and a deformation analysis step.

[0054] In the analytical model creation process, an analytical model of the natural ground is created. In the seepage analysis process, a seepage analysis of the analytical model is performed to determine changes in the degree of saturation of the elements of the analytical model due to drying and flooding. In the strength ratio estimation process, the changes in the degree of saturation of the elements of the analytical model are input into a strength reduction model in the aforementioned method for estimating the strength ratio of rock to estimate the strength ratio of the elements of the analytical model. In the deformation analysis process, deformation analysis of the analytical model is performed using the strength ratios of the elements of the analytical model.

[0055] The analysis model creation step, seepage flow analysis step, and strength ratio estimation step allow for estimation of strength distribution based on changes in the saturation degree of the ground. The deformation analysis step using the estimated strength distribution allows for accurate estimation of deformation of the ground due to groundwater flow, etc. The ground deformation analysis device 1, ground deformation analysis method, and program of the embodiment can be used for predicting future deformation of mountain tunnels and designing countermeasures.

[0056] The deformation analysis unit uses the strength ratio of the elements of the analytical model to determine the adhesive force of the elements of the analytical model, and performs deformation analysis of the analytical model. This allows the deformation of the ground to be estimated with high accuracy.

[0057] Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and changes, combinations, deletions, etc. of the configuration are also included within the scope that does not deviate from the gist of the present invention. [Explanation of symbols]

[0058] 1...ground rock deformation analysis device, 10...analysis model creation section, 20...seepage flow analysis section, 30...strength ratio estimation section, 40...deformation analysis section.

Claims

1. A first testing step of determining the strength of a first specimen which is a rock specimen; A second test step of drying the specimen to prepare a second specimen, and determining the degree of saturation of the second specimen by assuming that the degree of saturation of the first specimen is 1; A third test step of drying the specimen in the same manner as the second specimen and then submerging it in water to prepare a third specimen, determining the strength of the third specimen, and determining a strength ratio of the third specimen to the strength of the first specimen; a strength degradation model creation step of creating a strength degradation model showing a relationship between a change in the degree of saturation due to drying and submersion of the rock and the strength ratio of the rock to the strength of the first specimen, based on the saturation degrees and strength ratios of the second and third specimens, assuming that the strength ratio of the second and third specimens is 1 and the degree of saturation of the third specimen is 1; A strength ratio estimation step of estimating a strength ratio of the rock by inputting a change in saturation degree due to drying and water soaking of the rock into the strength degradation model. A method for estimating rock strength ratios.

2. In the second test step, the test specimen is dried to a plurality of dryness levels to prepare a plurality of types of the second test specimens, and the degree of saturation of the plurality of types of the second test specimens is determined; In the third test step, the test specimen is dried in the same manner as the plurality of types of second test specimens, and then submerged in water to prepare a plurality of types of third test specimens, and a strength ratio of the plurality of types of third test specimens is obtained; In the strength reduction model creation step, a linear interpolation is performed between the strength ratios of the first specimen and the plurality of types of third specimens, and a linear interpolation is performed between the strength ratios of the second specimen and the third specimen that have experienced similar drying, to create the strength reduction model. The method for estimating strength ratio of rocks according to claim 1 .

3. an analytical model creation unit that creates an analytical model of the natural ground; a seepage analysis unit that performs a seepage analysis of the analysis model to determine a change in saturation of an element of the analysis model due to drying and flooding; a strength ratio estimating unit that inputs a change in the degree of saturation of the element of the analysis model into the strength degradation model in the rock strength ratio estimating method according to claim 1 or 2, and estimates a strength ratio of the element of the analysis model; A deformation analysis unit that performs a deformation analysis of the analytical model using the intensity ratio of the elements of the analytical model. A device for analyzing ground deformation.

4. the deformation analysis unit uses a strength ratio of an element of the analytical model to obtain an adhesive force of the element of the analytical model, and performs a deformation analysis of the analytical model. The natural ground deformation analysis device according to claim 3.

5. The computer of the rock deformation analysis device an analytical model creation process for creating an analytical model of the natural ground; a seepage analysis step of performing a seepage analysis of the analytical model to determine a change in saturation of an element of the analytical model due to drying and flooding; an element strength ratio estimating step of estimating a strength ratio of the element of the analysis model by inputting a change in the degree of saturation of the element of the analysis model into the strength degradation model in the rock strength ratio estimating method according to claim 1 or 2; and performing a deformation analysis process of performing a deformation analysis of the analytical model using the intensity ratios of the elements of the analytical model. A method for analyzing ground deformation.

6. The computer of the rock deformation analysis device an analytical model creation process for creating an analytical model of the natural ground; a seepage analysis step of performing a seepage analysis of the analytical model to determine a change in saturation of an element of the analytical model due to drying and flooding; an element strength ratio estimating step of estimating a strength ratio of the element of the analysis model by inputting a change in the degree of saturation of the element of the analysis model into the strength degradation model in the rock strength ratio estimating method according to claim 1 or 2; and a deformation analysis step of performing a deformation analysis of the analytical model using the intensity ratios of the elements of the analytical model. program.

Images