Method for selecting deformation modulus of soft layer belt
By classifying and measuring point arrangement of weak layer belts, carrying out pressure-bearing plate tests in the direction of vertical layer belts, combining the principle of common bearing, calculating the deformation modulus of weak layer belts, solving the problem of distortion of test results in the existing technology, and achieving more reliable deformation modulus selection.
Patent Information
- Application Number
- CN202510304455.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2025-07-11
AI Technical Summary
When testing the deformation modulus of weak layer bands, the thickness of the layer bands causes distortion of the test results, making it difficult to accurately obtain the deformation modulus.
By classifying and measuring point arrangement of weak layer belts, carrying out pressure plate tests in the direction of vertical layer belts, obtaining the comprehensive deformation modulus, and based on the principle of common bearing, the deformation modulus of weak layer belts is calculated, and considering the influence of rock mass properties and thickness, a reliable deformation modulus selection method is established.
The test deviation caused by the thin layer band thickness is effectively eliminated, and a more reliable deformation modulus value of the weak layer band is obtained, which is simple and easy to promote.
Smart Images
Figure CN120293666A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of rock mass engineering, and particularly relates to a method for selecting the deformation modulus of a weak layer zone. Background Art
[0002] Weak layer zones are weak structural planes or weak zones with certain thickness and weak properties. Their thickness can range from a few centimeters to dozens of centimeters, and their extension length can range from dozens of meters to several kilometers. The most common material compositions of weak layer zones are mud, debris, gravel, etc., and some are composed of relatively weak rocks. Due to the existence of weak layer zones, the rock mass is prone to sliding along them, resulting in large-scale damage to the rock mass and endangering engineering construction. Therefore, during the engineering construction process, it is very important to test the physical and mechanical properties of weak layer zones.
[0003] The deformation modulus is particularly important for engineering layout and structural design and is a core parameter in rock mass engineering design. The deformation modulus of weak layer zones is generally obtained by testing with a rigid bearing plate method. However, the thickness of weak layer zones is often less than the diameter of the bearing plate. This causes the rock mass above and below the layer zone to bear the load when loading in the direction parallel to the layer zone, resulting in distortion of the test value of the deformation modulus. When loading perpendicular to the layer zone, since the depth range affected by the test load is 3 times the diameter of the bearing plate, which is greater than the thickness of the layer zone, the test value of the deformation modulus is actually the comprehensive deformation modulus of the weak layer zone and the underlying rock mass, and the test value of the deformation modulus is on the high side. Based on this, there is a need to establish an accurate and reliable method for selecting the deformation modulus. Summary of the Invention
[0004] This application provides a method for selecting the deformation modulus of a weak layer zone, which can effectively eliminate the test deviation caused by the thin thickness of the weak layer zone and obtain more reliable results.
[0005] The method for selecting the deformation modulus of the weak layer zone provided by this application includes the following steps:
[0006] 1) Classify the weak layer zone and arrange measuring points to ensure that each classified weak layer zone has a preset number of measuring points;
[0007] 2) Conduct a bearing plate test on the rock mass below the measuring point to obtain the deformation modulus value;
[0008] 3) Conduct a bearing plate test on the measuring points of the weak layer zone in the direction perpendicular to the layer zone to obtain the corresponding comprehensive deformation modulus value;
[0009] 4) Measure the thickness of the weak layer at the measuring point and calculate the thickness of the underlying rock mass participating in the test;
[0010] 5) Based on the principle of common bearing, obtain the calculation formula for the deformation modulus of the weak layer zone, substitute the known quantities obtained or calculated, and obtain the deformation modulus of the weak layer zone;
[0011] 6) According to the calculation formula of the deformation modulus of the weak layer zone, substitute the comprehensive deformation modulus obtained at each measuring point, the deformation modulus of the underlying rock mass, the thickness of the weak layer zone, and the participation thickness of the underlying rock mass to calculate the deformation modulus value of the weak layer zone at this measuring point;
[0012] 7) Establish the principle for determining the deformation modulus of the weak layer zone. Based on the average value of the deformation moduli of each measuring point of the same type, determine the geological recommended value of the deformation modulus of the weak layer zone of this type.
[0013] In addition, the method for selecting the deformation modulus of the weak layer zone provided in this application may also have the following additional technical features:
[0014] In an alternative solution, step 3) includes the following steps when obtaining the corresponding comprehensive deformation modulus value:
[0015] According to the pressure-deformation curves obtained at each test point, select a data segment for calculating the deformation modulus. The basic calculation formula is as follows:
[0016]
[0017] In the formula, E is the comprehensive deformation modulus (MPa), W is the total deformation of the rock mass surface (cm), P represents the pressure (MPa), D is the diameter of the bearing plate (cm), and μ is the Poisson's ratio of the rock mass; since the thickness of the weak layer zone and the thickness of the deep rock formation within the range of 3 times the diameter (d) of the bearing plate at the test point are measured, the obtained test deformation modulus value is the comprehensive deformation modulus of the weak layer zone and the underlying rock mass.
[0018] In an alternative solution, step 4) includes the following steps:
[0019] Define the thickness of the weak layer at the measuring point as H1, and the thickness of the underlying rock mass participating in the test as H2. Since the influence depth range of the test load of the bearing plate is 3 times the diameter of the bearing plate, the load is actually jointly borne by the weak layer zone and the deep rock mass. Thus, it can be obtained that: the participation thickness of the underlying rock mass is 3 times the diameter minus the thickness of the weak layer zone, that is, H2 = 3d - H1.
[0020] In an alternative solution, step 5) includes the following steps:
[0021] According to the principle of joint bearing, the known comprehensive deformation modulus can be expressed as:
[0022]
[0023] The deformation modulus of the weak layer zone is an unknown quantity, and the calculation formula is:
[0024]
[0025] Wherein, E is the equivalent comprehensive deformation modulus (GPa) of the soft layer zone and the underlying rock mass, E1 is the deformation modulus value of the fault zone, and E2 is the deformation modulus (GPa) of the underlying rock mass.
[0026] In an alternative solution, in step 1), when classifying the soft layer zone, it is refined according to the nature of the soft layer zone; when arranging the measuring points, the number of measuring points for each classified soft layer zone is not less than 4.
[0027] In an alternative solution, in step 7), when establishing the principle for determining the deformation modulus value of the soft layer zone, the influencing factors of excavation unloading relaxation, geological representativeness, deformation time effect, size effect, as well as the test method and the number of tests need to be considered;
[0028] The established principle for determining the deformation modulus value of the soft layer zone includes: taking the average deformation modulus of each classified soft layer zone as the upper limit, and reducing it by 20 - 30% on this basis as the lower limit; for the soft layer zone without tests, it is appropriately increased on the basis of the poorer type of structural plane, so as to obtain the recommended reliable deformation modulus value corresponding to each soft layer zone.
[0029] The beneficial effects of this application are as follows:
[0030] Based on the characteristic that it is difficult to directly obtain the deformation modulus of the soft layer zone due to its thin thickness, the method for selecting the deformation modulus of the soft layer zone in this application conducts tests in the direction perpendicular to the layer zone to obtain the comprehensive deformation modulus, and establishes a method for indirectly obtaining the deformation modulus of the soft layer zone through the principle of jointly bearing with the underlying rock mass, eliminating the test deviation caused by the thin thickness of the soft layer zone. This method is simple and easy to promote, and the selection result is more reliable.
[0031] It should be understood that the above general description and the following detailed description are only exemplary and do not limit this application. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 It is a schematic flow chart of the method for selecting the deformation modulus of the soft layer zone provided by this application;
[0033] Figure 2 It is a schematic diagram of the deformation test of the soft layer surface.
[0034] The accompanying drawings here are incorporated into the description and form a part of this description, showing the embodiments consistent with this application, and are used together with the description to explain the principles of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0035] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.
[0036] It should be clear that the described embodiments are only a part of the embodiments of this application, rather than all embodiments. Based on the embodiments in this application, all other technical solutions obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by this application.
[0037] The terms used in the embodiments of this application are only for the purpose of describing specific embodiments, and are not intended to limit this application. The singular forms "a", "the", and "said" used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.
[0038] It should be understood that the term "and / or" used herein is only a relationship describing the associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.
[0039] As Figure 1-2 shown, the embodiments of this application provide a method for selecting the deformation modulus of a soft layer zone. The method for selecting the deformation modulus of the soft layer zone mainly includes the following steps:
[0040] 1) Classify the soft layer zone and arrange measuring points to ensure that each classified soft layer zone has a preset number of measuring points;
[0041] When classifying the soft layer zone, it is refined according to the nature of the soft layer zone; when arranging the measuring points, the number of measuring points for each classified soft layer zone is not less than 4 to minimize the discreteness of the test results.
[0042] 2) Conduct a bearing plate test on the rock mass below the measuring point to obtain the deformation modulus value; the thickness of the rock mass below is relatively large and common, and a relatively reliable deformation modulus value can be obtained by general testing methods.
[0043] 3) Conduct a bearing plate test on the measuring points of the soft layer zone in the direction perpendicular to the layer zone to obtain the corresponding comprehensive deformation modulus value;
[0044] According to the pressure-deformation curves obtained at each test point, select a data segment for the calculation of the deformation modulus. The basic calculation formula is as follows:
[0045]
[0046] In the formula, E is the comprehensive deformation modulus (MPa), W is the total deformation of the rock mass surface (cm), P represents the pressure (MPa), D is the diameter of the bearing plate (cm), and μ is the Poisson's ratio of the rock mass.
[0047] Since the thickness of the soft layer zone and the thickness of the deep rock formation within the range of 3 times the diameter (d) of the bearing plate are measured at the test points, the obtained test deformation modulus value is the combined deformation modulus of the soft layer zone and the underlying rock mass.
[0048] 4) Measure the thickness of the soft layer at the measuring point and calculate the thickness of the underlying rock mass participating in the test;
[0049] Define the thickness of the soft layer at the measuring point as H1 and the thickness of the underlying rock mass participating in the test as H2. Since the influence depth range of the test load of the bearing plate is 3 times the diameter of the bearing plate, the load is actually jointly borne by the soft layer zone and the deep rock mass. Thus, it can be obtained that: the thickness of the underlying rock mass participating is 3 times the diameter minus the thickness of the soft layer zone, that is, H2 = 3d - H1.
[0050] 5) Based on the principle of joint bearing, obtain the calculation formula for the deformation modulus of the soft layer zone, substitute the known quantities obtained or calculated, and obtain the deformation modulus of the soft layer zone;
[0051] According to the principle of joint bearing, the known combined deformation modulus can be expressed as:
[0052]
[0053] The deformation modulus of the soft layer zone is an unknown quantity, and the calculation formula is:
[0054]
[0055] In the formula, E is the equivalent combined deformation modulus of the soft layer zone and the underlying rock mass (GPa), E1 is the deformation modulus value of the fault zone, and E2 is the deformation modulus of the underlying rock mass (GPa).
[0056] 6) According to the above formula, calculate the deformation modulus values of the soft layer zones of each type and each measuring point; substitute the combined deformation modulus, the deformation modulus of the underlying rock mass, the thickness of the soft layer zone, and the thickness of the underlying rock mass participating obtained for each measuring point, and calculate the corresponding deformation modulus value of the soft layer zone at this measuring point.
[0057] 7) Establish the principle for determining the deformation modulus value of the soft layer zone. According to the average value of the deformation modulus of each measuring point of the same type, determine the geological recommended value of the deformation modulus of this type of soft layer zone;
[0058] Calculate the average deformation modulus value of each type of soft layer zone. Considering influencing factors such as excavation unloading relaxation, geological representativeness, deformation time effect, size effect, as well as test methods and the number of tests, establish the principle for determining values: take the average deformation modulus of each type of soft layer zone as the upper limit, and reduce it by 20 - 30% on this basis as the lower limit; for the soft layer zones without tests, appropriately increase it on the basis of the worse type of structural plane. In this way, the recommended reliable deformation modulus values corresponding to each type of soft layer zone are obtained.
[0059] The method for selecting the deformation modulus of the weak layer zone in this embodiment is based on the characteristics that the weak layer zone is thin in thickness and it is difficult to directly obtain its deformation modulus. Vertical testing in the direction of the layer zone is carried out to obtain the comprehensive deformation modulus, and based on the principle of jointly bearing with the underlying rock mass, a method for indirectly obtaining the deformation modulus of the weak layer zone is established. Due to the testing deviation caused by the thin thickness of the weak layer zone, the selection result of this method for the deformation modulus of the weak layer zone is more reliable.
[0060] Example 1: Exploratory adits were carried out on the geology of a certain hydropower project, and geological values were determined for the deformation moduli of multiple weak layer zones at the site.
[0061] According to the properties of the weak layer zones at the project site, they were divided into three types: rock debris intercalated with mud type, rock block and rock debris type, and mud intercalated with rock debris type. Four measuring points were arranged for each type of weak layer zone, and the thicknesses of different and the same types of weak layer zones were unequal.
[0062] Deformation modulus test experiments were carried out on the rock mass below the weak layer zone at each measuring point to obtain the deformation modulus value E2 of the rock mass below each measuring point. As shown in the following table, taking measuring point A1 as an example, the underlying rock mass is tuff, and the measured deformation modulus of tuff is 2.0 GPa.
[0063] Rigid bearing plate tests were carried out on 12 measuring points. The diameter of the bearing plate is 0.5 m, and the load influence depth is 1.5 m. According to the test results, the comprehensive deformation modulus value E of each measuring point was calculated; the deformation modulus obtained for measuring point A1 through the bearing plate test is 0.19 GPa.
[0064] The thickness H1 of the weak layer zone at each measuring point was measured, and the bearing thickness H2 of the underlying rock mass was calculated; the thickness of the weak layer zone at measuring point A1 is 0.3 m, and the bearing thickness of the underlying rock mass is 1.2 cm.
[0065] The comprehensive deformation modulus, the thickness of the weak layer zone, the thickness of the underlying rock mass, and the deformation modulus value of each measuring point were substituted into the calculation formula to obtain the deformation modulus value of the weak layer zone. Substituting the relevant values of measuring point A1 into the formula, the deformation modulus E1 of the weak layer zone at this measuring point was obtained as 0.041 GPa.
[0066]
[0067] In this way, following the method of measuring point A1, the deformation modulus values of the weak layer zones at 12 measuring points were obtained in sequence. After sorting by type, the average deformation modulus value corresponding to each type of weak layer zone. In this embodiment, the average deformation modulus value obtained for the four measuring points of the rock debris intercalated with mud type is 0.054 GPa.
[0068] According to the geological value determination principle, taking the average deformation modulus of each type of weak layer zone as the upper limit, and reducing it by 20 - 30% on this basis as the lower limit, taking a reduction of 26%, the recommended value for the rock debris intercalated with mud type is 0.04 - 0.054 GPa.
[0069]
[0070] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various modifications and changes can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.
Claims
1. A method for selecting the deformation modulus of a weak layer zone, characterized in that, It includes the following steps: 1) Classify the weak layer zone and arrange measuring points to ensure that each classified weak layer zone has a preset number of measuring points; 2) Conduct a bearing plate test on the rock mass below the measuring point to obtain the deformation modulus value; 3) Conduct a bearing plate test on the measuring points of the weak layer zone in the direction perpendicular to the layer zone to obtain the corresponding comprehensive deformation modulus value; 4) Measure the thickness of the weak layer at the measuring point and calculate the thickness of the rock mass below participating in the test; 5) Based on the principle of common bearing, obtain the calculation formula for the deformation modulus of the weak layer zone, substitute the known quantities obtained or calculated, and obtain the deformation modulus of the weak layer zone; 6) According to the calculation formula for the deformation modulus of the weak layer zone, substitute the comprehensive deformation modulus, the deformation modulus of the rock mass below, the thickness of the weak layer zone, and the thickness of the rock mass below participating in the test obtained at each measuring point, and calculate the deformation modulus value of the weak layer zone at this measuring point; 7) Establish the value-taking principle for the deformation modulus of the weak layer zone, and determine the geological recommended value for the deformation modulus of this type of weak layer zone according to the average value of the deformation moduli of each measuring point of the same type; 2. The method for selecting the deformation modulus of the weak layer zone according to claim 1, characterized in that When obtaining the corresponding comprehensive deformation modulus value in step 3), it includes the following steps: According to the pressure-deformation curves obtained at each test point, select a data segment to calculate the deformation modulus. The basic calculation formula is as follows: In the formula, E is the comprehensive deformation modulus (MPa), W is the total deformation of the rock mass surface (cm), P represents the pressure (MPa), D is the diameter of the bearing plate (cm), and μ is the Poisson's ratio of the rock mass; since the thickness of the weak layer zone and the thickness of the deep rock formation within the range of 3 times the diameter of the bearing plate (d) of the test point are measured, the obtained test deformation modulus value is the comprehensive deformation modulus of the weak layer zone and the rock mass below.
3. The method for selecting the deformation modulus of the weak layer zone according to claim 2, characterized in that Step 4) includes the following steps: Define the thickness of the weak layer at the measuring point as H1, and the thickness of the rock mass below participating in the test as H2. Since the influence depth range of the bearing plate test load is 3 times the diameter of the bearing plate, the load is actually jointly borne by the weak layer zone and the deep rock mass. Thus, it can be obtained that: the thickness of the rock mass below participating is 3 times the diameter minus the thickness of the weak layer zone, that is, H2 = 3d - H1.
4. The method for selecting the deformation modulus of the weak layer zone according to claim 3, characterized in that Step 5) includes the following steps: According to the principle of common bearing, the known comprehensive deformation modulus can be expressed as: The deformation modulus of the weak layer zone is an unknown quantity, and the calculation formula is: In the formula, E is the equivalent comprehensive deformation modulus of the weak layer zone and the rock mass below (GPa), E1 is the deformation modulus value of the fault zone, and E2 is the deformation modulus of the rock mass below (GPa).
5. The method for selecting the deformation modulus of the weak layer zone according to any one of claims 1-4, characterized in that In step 1), when classifying the weak layer zone, it is refined according to the nature of the weak layer zone; when arranging the measuring points, the number of measuring points for each classified weak layer zone is not less than 4.
6. The method for selecting the deformation modulus of the soft layer zone according to claim 5, characterized in that, In step 7), when establishing the value-taking principle for the deformation modulus of the weak layer zone, factors such as excavation unloading relaxation, geological representativeness, deformation time effect, size effect, and test method and test quantity need to be considered; The established value-taking principle for the deformation modulus of the weak layer zone includes: taking the average deformation modulus of each classified weak layer zone as the upper limit, and reducing it by 20 - 30% on this basis as the lower limit; For the weak layer zones without tests, appropriately increase it on the basis of the poorer type of structural plane to obtain the recommended reliable deformation modulus value for each type of weak layer zone.