Stability evaluation method for built underground cavern

Abstract

The invention belongs to the technical field of geological disaster risk assessment, and particularly relates to a stability evaluation method for a built underground cavern, which comprises the following steps of: 1, collecting basic data: collecting geological environment condition data of an area where the underground cavern is located; step 2, hidden danger type division: dividing underground cavern hidden dangers into two types of cavern surrounding rock instability and cavern water seepage; 3, determining the risk level of the geological hidden danger: determining the hazard degree and the risk level of the hidden danger according to the relevant provisions of the Code for Assessment of Risk of Geological Disasters; 4, evaluating the traffic importance and the use frequency of the cavern; according to the method, improvement is carried out on the basis of'geological disaster risk assessment specifications', and specific indexes for hidden danger type division, characteristics and development degree of the built underground cavern are added, so that the assessment is more systematic, comprehensive and targeted.

Description

Technical Field

[0001] The invention belongs to the technical field of geological disaster risk assessment, and in particular relates to a stability assessment method for a built underground cavern. Background Art

[0002] The "Code for Geological Hazard Risk Assessment" (GB / T 40112-2021) provides a basic framework for geological hazard risk assessment, but its application to the stability assessment of existing underground caverns is insufficiently targeted. The stability assessment of existing underground caverns requires comprehensive consideration of factors such as hazard type, development level, transportation importance, and frequency of use. Currently, there is a lack of a systematic and quantitative method to comprehensively assess the stability of existing underground caverns and propose appropriate treatment measures.

[0003] The present invention designs a stability evaluation method for a built underground cavern to solve the above problems. Summary of the Invention

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: A stability evaluation method for a built underground cavern comprises: Step 1: Basic Data Collection: Collect geological and environmental data on the area where the underground cavern is located. This data includes information on meteorology and hydrology, regional geological conditions, topography and landforms, stratum lithology, geological structure, weathering unloading, hydrogeological conditions, geostress, and the impact of human activities on the geological environment. Also collect construction data, operation records, and past geological disaster records of the underground cavern. Step 2: Classify the hidden danger types: Categorize underground cavern hidden dangers into two types: cavern surrounding rock instability and cavern water seepage. Cavern surrounding rock instability is further subdivided into two subtypes: support defects and surrounding rock deformation. Step 3: Determine the risk level of geological hazards: According to the relevant provisions of the "Geological Hazard Risk Assessment Standard" (GB / T40112-2021), determine the hazard level and risk level of the hazards; Step 4: Assess the importance and frequency of traffic in underground caverns: Evaluate the importance and frequency of traffic in underground caverns based on factors such as their role in the project, traffic volume, and whether detours are possible, and categorize them into different levels. Step 5. Comprehensive Assessment and Development of Treatment Measures: Conduct a comprehensive assessment of the stability of the underground cavern based on the development level of hidden dangers, the degree of hazard, the traffic importance of the cavern, and the frequency of use. Develop corresponding treatment measures based on the assessment results, including strengthening support, reinforcing the structure, draining water seepage, regular inspections, and local repairs.

[0005] As a preferred solution, the second step also includes determining the characteristics of hidden dangers and indicators of the degree of development of hidden dangers: evaluating the degree of development of hidden dangers based on specific indicators, including the anchor cable breakage, anchor head crushing degree, and steel mesh exposure of support defects, as well as the sprayed concrete cracking width and shear deformation trend of surrounding rock deformation, the water discharge status of cavern seepage, and water clarity.

[0006] As a preferred solution, in the step of determining the hidden danger characteristics and hidden danger development degree indicators, For support defects, the development degree is further divided according to information such as the operation status of anchor cables and the current status of system shotcrete; For surrounding rock deformation, the development degree is further divided based on information such as the crack width of the shotcrete and the deformation trend of the tunnel face slope; For cavern seepage, the development degree is divided by quantitative description of water discharge status, water clarity, and the operating status of drainage measures.

[0007] Compared with the existing technology, the advantages of the present invention are: 1. This invention improves upon the "Specifications for Geological Hazard Risk Assessment" (GB / T 40112-2021) by adding specific indicators for the classification, characteristics, and development levels of hidden dangers in existing underground caverns, making the assessment more systematic, comprehensive, and targeted.

[0008] 2. The present invention realizes the quantitative assessment of the stability of underground caverns through specific indicators of hidden danger development degree and evaluation standards of traffic importance and frequency of use, providing a basis for the operation unit to deal with it.

[0009] 3. The present invention takes into account the traffic importance and usage frequency of the cavern, making the treatment measures more scientific and reasonable, and can effectively ensure the safe operation of the underground cavern, reduce the risk of geological disasters, and reduce economic losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic flow chart of the method of the present invention. DETAILED DESCRIPTION

[0011] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following embodiments or drawings are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0012] A method for evaluating the stability of a built underground cavern, such as Figure 1 Shown, including: Step 1. Basic data collection: Collect geological environment data of the area where the underground cavern is located. The geological environment data include meteorology and hydrology, regional geological conditions, topography, lithology, geological structure, weathering unloading, hydrogeological conditions, ground stress, and the impact of human activities on the geological environment. Collect construction data, operation records, and past geological disaster records of the underground cavern.

[0013] Step 2: Classify the hidden danger types: Categorize underground cavern hidden dangers into two types: cavern surrounding rock instability and cavern water seepage. Cavern surrounding rock instability is further subdivided into two subtypes: support defects and surrounding rock deformation. The second step also includes determining the characteristics of hidden dangers and indicators of the degree of development of hidden dangers: evaluating the degree of development of hidden dangers based on specific indicators, including the anchor cable breakage, anchor pier head crushing, and exposed steel mesh of support defects, as well as the sprayed concrete cracking width and shear deformation trend of surrounding rock deformation, the water discharge status of cavern seepage, and water clarity.

[0014] Table 1 Hidden danger characteristics and hidden danger development degree indicators

[0015] In the step of determining the hidden danger characteristics and hidden danger development degree indicators, For support defects, the development degree is further divided according to information such as the operation status of anchor cables and the current status of system shotcrete; For surrounding rock deformation, the development degree is further divided based on information such as the crack width of the shotcrete and the deformation trend of the tunnel face slope; For cavern seepage, the development degree is divided by quantitative description of water discharge status, water clarity, and the operating status of drainage measures.

[0016] Step 3. Determine the hazard level of geological hazards: According to the relevant provisions of the "Geological Hazard Hazard Assessment Code" (GB∕T40112-2021), determine the degree of hazard and hazard level of the hazards.

[0017] Step 4: Assess the importance and frequency of traffic in underground caverns: Evaluate the importance and frequency of traffic in underground caverns based on factors such as their role in the project, traffic volume, and whether detours are possible, and categorize them into different levels. Table 2 Evaluation criteria for cavern traffic importance and frequency of use

[0018] Step 5. Comprehensive Assessment and Development of Treatment Measures: Conduct a comprehensive assessment of the stability of the underground cavern based on the development level of hidden dangers, the degree of hazard, the importance of transportation to the cavern, and the frequency of use. Based on the assessment results, formulate appropriate treatment measures, including strengthening support, reinforcing the structure, draining water seepage, regular inspections, and local repairs. After determining the hazard level of hidden dangers, add traffic importance and frequency of use evaluation indicators. After determining the hazard level of hidden dangers, traffic importance and frequency of use, list targeted suggestions for handling hidden dangers.

[0019] Table 3 Comprehensive assessment and treatment measures

[0020] Taking the underground caverns of a large hydropower station as an example, the specific implementation steps are as follows: 1. Collect basic information: Collect information on the geological environment conditions of the area where the underground cavern of the hydropower station is located, as well as the construction information and operation records of the cavern.

[0021] 2. On-site investigation to classify hidden danger types: Conduct on-site investigation of underground caverns to determine the types of hidden dangers, such as support defects, surrounding rock deformation, cavern water seepage, etc.

[0022] 3. Assess the risk level of geological hazards: Evaluate each hazard based on its characteristics and indicators of development level. For example, a cavern was found to have sprayed concrete cracks with a width of 20 mm and an extension length of 10 m. The indicators determined that the development level was medium. According to the specifications, the hazard level and risk level were medium. Comprehensively assessed, the risk level was medium.

[0023] 4. Assess the traffic importance and frequency of use of the cavern: The cavern is located in an area of medium traffic importance and medium frequency of use.

[0024] 5. Formulate treatment measures: Based on the comprehensive assessment results, formulate corresponding treatment measures. For the above-mentioned medium-risk spray-mix cracking hazards, and the cavern is located in an area with medium traffic importance and medium frequency of use, take treatment measures as soon as possible, such as local reinforcement, repair support, etc., and conduct regular inspections.

[0025] After completing the stability assessment of the underground cavern, professional personnel will be organized to carry out reinforcement and repair work in accordance with the formulated treatment measures to ensure that hidden dangers are dealt with in a timely manner.

[0026] After the treatment measures are implemented, the caverns are reviewed regularly to ensure that the hidden dangers do not recur, and other caverns are inspected regularly to promptly discover and deal with new hidden dangers.

[0027] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for evaluating the stability of a built underground cavern, characterized in that: include: Step 1: Basic Data Collection: Collect geological and environmental data on the area where the underground cavern is located. This data includes information on meteorology and hydrology, regional geological conditions, topography and landforms, stratum lithology, geological structure, weathering unloading, hydrogeological conditions, geostress, and the impact of human activities on the geological environment. Also collect construction data, operation records, and past geological disaster records of the underground cavern. Step 2: Classify the hidden danger types: Categorize underground cavern hidden dangers into two types: cavern surrounding rock instability and cavern water seepage. Cavern surrounding rock instability is further subdivided into two subtypes: support defects and surrounding rock deformation. Step 3: Determine the risk level of geological hazards: According to the relevant provisions of the "Geological Hazard Risk Assessment Standard" (GB∕T 40112-2021), determine the hazard level and risk level of the hazards; Step 4: Assess the importance and frequency of traffic in underground caverns: Evaluate the importance and frequency of traffic in underground caverns based on factors such as their role in the project, traffic volume, and whether detours are possible, and categorize them into different levels. Step 5. Comprehensive Assessment and Development of Treatment Measures: Conduct a comprehensive assessment of the stability of the underground cavern based on the development level of hidden dangers, the degree of hazard, the traffic importance of the cavern, and the frequency of use. Develop corresponding treatment measures based on the assessment results, including strengthening support, reinforcing the structure, draining water seepage, regular inspections, and local repairs.

2. The stability evaluation method for a built underground cavern according to claim 1, characterized in that: The second step also includes determining the characteristics of hidden dangers and indicators of the degree of development of hidden dangers: evaluating the degree of development of hidden dangers based on specific indicators, including the anchor cable breakage, anchor pier head crushing, and exposed steel mesh of support defects, as well as the sprayed concrete cracking width and shear deformation trend of surrounding rock deformation, the water discharge status of cavern seepage, and water clarity.

3. The stability evaluation method for a built underground cavern according to claim 2, characterized in that: In the step of determining the hidden danger characteristics and hidden danger development degree indicators, For support defects, the development degree is further divided according to information such as the operation status of anchor cables and the current status of system shotcrete; For surrounding rock deformation, the development degree is further divided based on information such as the crack width of the shotcrete and the deformation trend of the tunnel face slope; For cavern seepage, the development degree is divided by quantitative description of water discharge status, water clarity, and the operating status of drainage measures.

Images