A grading treatment method for crossing sludge flow sudden surge deposits of poor alteration zone

Abstract

The application belongs to the technical field of tunnel and underground engineering disaster prevention and reduction, and specifically discloses a grading treatment method for mudflow gushing and deposit of a tunnel passing through a poor alteration zone, which comprises the following steps: collecting information and parameters of the gushing disaster site; based on the information and parameters and a preset grading standard, performing danger grading on the deposit after the mudflow gushing; according to the danger grading result, using a construction measure corresponding to the danger grade to treat the deposit; wherein for the deposit of a low danger grade, direct dredging or sandbag counterpressure treatment is used, and for the deposit of a medium or high danger grade, a critical length for cleaning the deposit is calculated, and then at least one of segmented grouting, segmented excavation, full-face grouting or a prefabricated grouting wall is used for treatment based on the critical length. The application can safely and efficiently treat the mudflow gushing deposit in the tunnel passing through the poor alteration zone.

Description

Technical Field

[0001] This application belongs to the field of disaster prevention and mitigation technology for tunnels and underground engineering, and more specifically, relates to a graded treatment method for mudflow and silt deposits that surge through adverse alteration zones. Background Technology

[0002] As national infrastructure networks, including transportation and water conservancy projects, extend into deep mountains, canyons, and complex geological areas, tunnel construction inevitably traverses challenging geological formations such as fault fracture zones and hydrothermal alteration zones. These alteration zones are characterized by fractured rock structures, poor cementation, and are often accompanied by high-pressure, water-rich environments, making them highly susceptible to geological disasters such as sudden water and mudflows (mudflows). After such disasters occur, large amounts of mudflow debris often accumulate inside the tunnel, not only blocking construction access but also severely hindering subsequent rescue and resumption of work.

[0003] Currently, the handling of silt deposits following such sudden surges still faces severe challenges in engineering practice. While the silt deposits after a surge provide temporary passive support and act as a "plug" at the tunnel face, under the coupling effect of seepage and stress, hasty dredging can easily disrupt the existing temporary equilibrium, triggering secondary surge disasters such as soil erosion, piping, or even overall landslides. At the same time, existing dredging operations rely heavily on engineering analogies or experience-based judgments, lacking quantitative calculation models that comprehensively consider multiple factors such as altered rock type, water pressure, and silt particle size and density. This makes it difficult to accurately determine the safe critical length for a single dredging operation, often leading to instability due to "over-dredging" or delays due to "overly conservative" approaches. Furthermore, the lack of unified hazard classification and matching standards for silt of different sizes and properties means that the selection of existing treatment methods such as direct grouting, grout-stop walls, or counter-pressure often lacks scientific basis. This easily leads to a situation where insufficient reinforcement results in a recurrence of the accident, or excessive reinforcement wastes resources, failing to meet the engineering requirements for safe and efficient post-disaster emergency response.

[0004] Therefore, how to safely and efficiently handle mudflows and silt deposits in tunnels traversing adverse alteration zones is an urgent problem that needs to be solved. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this application is to provide a graded treatment method for mudflow surge deposits in tunnels crossing adverse alteration zones, which can safely and efficiently treat mudflow surge deposits in tunnels crossing adverse alteration zones.

[0006] To achieve the above objectives, in a first aspect, this application provides a method for graded treatment of mudflow deposits surging through adverse alteration zones, comprising the following steps:

[0007] S10, Collect on-site information and parameters of the sudden surge disaster, including residual material scale, siltation morphology, solid component particle size, water content, water pressure conditions of the surge section and adverse geological structure type;

[0008] S20, based on the information and parameters and the preset classification criteria, classify the hazard of the sediment after the mudflow surge;

[0009] S30. Based on the hazard classification results, construction measures corresponding to the hazard level are adopted to treat the silt. Among them, for silt with a low hazard level, direct dredging or sandbag back pressure is adopted. For silt with a medium or high hazard level, the critical length for silt removal is first calculated, and then at least one of the following methods is adopted for treatment based on the critical length: segmented grouting, segmented excavation, full-section grouting, or precast grout-stopping wall.

[0010] As a further preferred embodiment, in step S20, the preset grading standard includes primary indicators and secondary indicators. The primary indicators include silt, adverse geological conditions, and tunnel factors. The secondary indicators corresponding to the silt include residual silt size, silt morphology, main solid components of the residual silt, density, water content, and d. 30 The particle size range, the secondary indicators corresponding to the adverse geological conditions include type, dip angle, width of adverse geological zone, fault, karst, water pressure conditions and groundwater level, and the secondary indicators corresponding to the tunnel factors include burial depth and cross-sectional area.

[0011] As a further preferred option, in step S30, for silt of medium to high risk level, the critical length for silt removal is calculated. L The specific steps of 1 include:

[0012] S31, Mechanical modeling of tunnels traversing adverse geological zones;

[0013] S32, the water-rich adverse alteration zone is discretized into a series of nodes by the finite difference method, and the permeability is calculated based on the Laplace equation;

[0014] S33, combine force analysis to calculate the reaction pressure of the weak zone, and calculate the critical reaction pressure according to the search method. ;

[0015] S34, based on the critical counter pressure The critical length for clearing the silt was calculated according to the formula. L 1; where the formula is:

[0016]

[0017] In the formula, The diameter of the tunnel. For cohesion, The density of the sediment. It is the acceleration due to gravity. The coefficient of friction, This represents the lateral pressure coefficient.

[0018] As a further preferred option, the critical back pressure The calculation formula is:

[0019]

[0020] In the formula, The load on the triangular potential sliding zone by the weak zone at the top of the tunnel to be excavated is obtained by constructing a recursive relationship based on the force equilibrium equation of the disturbed zone and substituting it with the boundary conditions. To predict the width of the weak band; The horizontal penetration force in the triangular area in front of the front of the sudden surge; The vertical penetration force in the triangular area in front of the front of the sudden surge; It is the angle of inclination. ; It is the friction angle; The triangular area in front of the front of the sudden surge is severely affected.

[0021] As a further preferred embodiment, the hazard classification results in step S20 include Level I, Level II, Level III, Level IV, and Level V, wherein the low hazard level includes Level I and Level II, and the medium-to-high hazard level includes Level III, Level IV, and Level V.

[0022] As a further preferred option, for Class I hazardous silt, a direct dredging method is adopted, using a loader in conjunction with manual labor for cleaning, and following the principles of short advance and quick support.

[0023] As a further preferred option, for Class II hazardous silt, a sandbag counter-pressure measure is adopted. Specifically, sandbags are piled on the surface of the silt to form a counter-pressure retaining wall, and permeable hoses are buried to guide the water out. Cleaning is carried out after the pore water pressure dissipates and the soil consolidates.

[0024] As a further preferred option, in step S30, for Class III, IV, and V hazardous silt deposits, at least one of the following methods is employed: segmented grouting, segmented excavation, full-section grouting, and sealing with a poured concrete grout-stopping wall, combined with drainage through pressure relief holes, and ensuring that a reserved length is maintained during the cleaning process. L Less than the critical length for cleaning the silt L 1.

[0025] Secondly, this application provides a tiered treatment system for mudslide inrush sediment, used to implement the steps of the method described in any one of the above statements, including:

[0026] The parameter acquisition module is used to collect on-site information and parameters of the sudden surge disaster. The information and parameters include residual material scale, siltation morphology, solid particle size, water content, water pressure conditions of the surge section, and adverse geological structure type.

[0027] The hazard classification module is used to classify the hazard of the sediment after the mudflow based on the information and parameters and the preset classification criteria.

[0028] The disposal decision module is used to generate construction disposal plans corresponding to the hazard level based on the hazard classification results. Specifically, for low hazard levels, it generates direct dredging or sandbag counterpressure plans. For medium and high hazard levels, it first calculates the critical length for silt removal and then generates disposal plans based on the critical length, including at least one of the following methods: segmented grouting, segmented excavation, full-section grouting, or precast grout-stopping walls.

[0029] Thirdly, this application provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the method as described in any one of the above.

[0030] This application offers the following advantages: By constructing a quantitative grading evaluation system that integrates multi-source information, it overcomes the blindness of traditional experience-based judgments. It comprehensively considers multiple factors such as the scale, gradation, and water pressure of the sediment, enabling rapid and objective identification of sediment instability risks. Furthermore, this application proposes a critical length calculation model based on the seepage-stress coupling mechanism, accurately determining the maximum safe excavation step distance to maintain the balance of the sediment's "blocking effect," effectively avoiding the risk of secondary surges caused by blind dredging and delays due to excessive conservatism. Further, this application establishes a differentiated treatment technology system based on "grading and matching," which adaptively matches measures such as direct dredging, backpressure diversion, segmented / full-section grouting, or grout stop wall sealing according to the risk level and critical length. This avoids excessive reinforcement waste in low-risk conditions while ensuring the reliability of treatment in high-risk conditions, significantly reducing post-disaster treatment costs and achieving an organic unity of engineering safety, efficiency, and economic benefits. Attached Figure Description

[0031] Figure 1 This is a flowchart of the graded treatment method for mudflow surge deposits in crossing adversely altered zones, as provided in this application. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0033] To achieve safe and efficient disposal of mudflow sluice deposits in tunnels traversing adverse alteration zones, this application provides a graded disposal method for mudflow sluice deposits in such zones. This method comprehensively considers multi-source geological information to achieve rapid classification of the hazard of the sluice deposits and calculates the critical length for dredging based on a mechanical model, thereby recommending scientific and appropriate disposal measures, providing theoretical support and technical guarantee for the safe and efficient resumption of tunnel construction after disasters.

[0034] like Figure 1 As shown, this application provides a graded treatment method for mudflow sluice deposits traversing adversely altered zones, including steps S10 to S30, detailed below:

[0035] Step S10: Information and parameter collection at the site of the sudden surge disaster

[0036] Following a mudslide outburst, an on-site survey procedure should be initiated immediately. Data collected should cover key sediment characteristic parameters and geological environmental parameters, specifically including: residual sediment size, sediment morphology (half-section / full-section length), solid particle size, water content, water pressure conditions at the outburst cross-section, and types of adverse geological structures.

[0037] Step S20: Hazard classification of mudflow surge and sediment deposits

[0038] The hazard classification of sediments after a mudflow surge is based on sediment characteristic parameters, geological environment parameters, and preset classification standards.

[0039] Step S30: Differentiated treatment decisions based on hazard level

[0040] Different construction measures are adopted according to different hazard levels. For low-risk silt, a rapid treatment method of direct dredging and sandbag back pressure is adopted. For medium- and high-risk silt, after calculating the critical length for silt removal, the method of segmented grouting, segmented excavation, full-section grouting, and prefabricated grout walls is adopted to remove the silt.

[0041] The graded treatment method for mudflow surges and silt deposits in adversely altered zones provided in this application has the following effects: By constructing a quantitative graded evaluation system based on multi-source information fusion, it overcomes the blindness of traditional experience-based judgments and can comprehensively consider multiple factors such as residual material size, gradation, and water pressure to achieve rapid and objective identification of silt instability risks. Based on this, this application proposes a critical length calculation model for cleaning based on the seepage-stress coupling mechanism, accurately determining the maximum safe excavation step distance to maintain the balance of the "blocking effect" of the silt mass, effectively avoiding the risk of secondary surges caused by blind dredging and the delays caused by excessive conservatism. Furthermore, this application establishes a differentiated treatment technology system of "graded-matching," which can adaptively match measures such as direct dredging, backpressure diversion, segmented / full-section grouting, or grout stop wall sealing according to the risk level and critical length. This avoids excessive reinforcement waste in low-risk conditions and ensures the reliability of treatment in high-risk conditions, significantly reducing post-disaster treatment costs and achieving an organic unity of engineering safety, efficiency, and economic benefits.

[0042] In one embodiment, the technical solution for achieving the above objective can be specifically as follows:

[0043] Step S1: Immediately initiate the on-site survey procedure after a debris flow outburst disaster. Data collection should cover key sediment characteristic parameters and geological environmental parameters, specifically including: residual sediment size, sediment morphology (half-section / full-section length), solid particle size, water content, and water pressure conditions and adverse geological structure types at the outburst cross-section.

[0044] Step S2: Based on the characteristic parameters of the sediment and the geological environment parameters and the preset classification standards, the hazard classification of the sediment after the mudflow surge is carried out. The hazard classification of the sediment after the mudflow surge is shown in Table 1.

[0045] Table 1 Hazard Classification of Deposits from Mudslide Outbursts

[0046]

[0047] Step S3: Differentiated Response Decisions Based on Hazard Level

[0048] Different construction measures are adopted according to different hazard levels. For low-risk silt, a rapid treatment method of direct dredging and sandbag back pressure is adopted. For medium- and high-risk silt, after calculating the critical length for silt removal, the method of segmented grouting, segmented excavation, full-section grouting, and prefabricated grout walls is adopted to remove the silt.

[0049] For Class I hazardous silt deposits, due to their large particle size, high permeability, and low susceptibility to soil erosion, a direct dredging method is adopted. This involves using loaders in conjunction with manual labor for dredging, following the principles of "short advances and rapid support."

[0050] For Class II hazardous silt deposits, sandbag counterpressure measures are adopted. Sandbags are piled on the surface of the silt deposit to form a counterpressure retaining wall. At the same time, permeable hoses are buried to guide the water out. Cleaning is carried out after the pore water pressure dissipates and the soil consolidates.

[0051] For silt of medium to high risk levels (Level III, IV, and V), a method of segmented grouting, segmented excavation, full-section grouting, and sealing with poured concrete grout-stopping walls, combined with drainage through pressure relief holes, can be adopted. During the cleaning process, it is essential to ensure that sufficient length is reserved. L < L 1.

[0052] The specific steps for calculating the critical length for silt removal are as follows:

[0053] First, a mechanical model was created based on the tunnel's geometry, dividing the tunnel into six regions: undisturbed soil above the groundwater level; saturated soil below the groundwater level and above the soil arching effect zone that was not disturbed by excavation; the soil arching region; the disturbed region within the adverse alteration zone; the triangular region in front of the tunnel face before the sudden surge; and the silt deposits caused by the sudden surge of mudflow.

[0054] Then, the water-rich, poorly altered zone is discretized into a series of nodes using the finite difference method and substituted into the Laplace equation to obtain the permeability. The calculation formula is as follows:

[0055]

[0056] In the formula The density of water, The horizontal hydraulic gradient, Let A be the vertical hydraulic gradient, A be the coefficient matrix, h be the head at all nodes, and b be the constant vector.

[0057] For internal nodes, the coefficient matrix A is:

[0058]

[0059] In the formula, D is the coefficient of the corresponding central node. , Adjacent to the main diagonal, corresponding Nodes adjacent in direction. The coefficients of the left node, Right node coefficients , The bandwidth of the distance from the main diagonal is correspond Nodes adjacent in direction. The coefficients of the nodes below , coefficients of the upper node .

[0060] For nodes on the boundary, the matrix needs to be adjusted according to the boundary condition type. The corresponding rows and vectors Make corrections:

[0061] (1) Waterproof boundary: The nodes satisfy or When this occurs, it indicates that the boundary normal flux is zero, and the main diagonal element is modified. and the corresponding neighborhood coefficients, while maintaining .

[0062] (2) Dirichlet boundary: when the node has a fixed head When, let the matrix No. The main diagonal element of the row All other off-diagonal elements are 0, and the right-hand term is set to 0. At this point, the equation degenerates into an identity.

[0063] (3) Specific boundaries of the working face: For nodes in the water-rich, soft zone near the working face, the hydraulic head distribution is determined by the geometric location (e.g., ).make , ( (Node elevation or distance).

[0064] The permeability of the alteration zone can be calculated using the above formula. Combined with stress analysis, the counterpressure of the weak zone can be calculated. The critical counterpressure can then be calculated using the search method. The calculation formula is as follows:

[0065]

[0066] In the formula q 4 represents the load on the triangular potential sliding zone from the weak zone at the top of the tunnel to be excavated. This load can be constructed based on the force equilibrium equation of the disturbed zone. Substitute the recurrence relation into the boundary conditions Please provide a solution.

[0067]

[0068] load q The formula for calculating 3 is:

[0069]

[0070] Then, based on the calculated critical back pressure, the critical length for silt removal is calculated using the following formula:

[0071]

[0072] In the formula The coefficient of friction is (0.5~0.6). This represents the lateral pressure coefficient.

[0073] The following is a specific implementation example of this application:

[0074] Take a deep-buried railway tunnel that traverses a water-rich, poorly altered zone as an example. The tunnel area is mainly composed of early Yanshanian intrusive granite, with a diameter of 15 m and a depth of 270 m. There is a water-rich, poorly altered zone in the tunnel, 25 m wide, with a dip angle of approximately 85°, and the groundwater level is located at 110 m.

[0075] Table 2 Tunnel Geotechnical Parameters

[0076]

[0077] Step 1: Information and parameter collection at the site of the sudden surge disaster

[0078] Following a mudslide outburst, an on-site survey procedure should be initiated immediately. Data collected should cover key sediment characteristic parameters and geological environmental parameters, specifically including: residual sediment size, sediment morphology (half-section / full-section length), solid particle size, water content, water pressure conditions at the outburst cross-section, and types of adverse geological structures.

[0079] Step 2: Hazard classification of mudslide surge and sediment deposits

[0080] Based on the characteristic parameters of the sediment and geological environment parameters, and the preset classification standards, the sediment after the mudslide inrush was classified into hazardous categories. Because the cumulative volume of mud and sand released after the tunnel inrush reached 2000 m³, and approximately 70 m of it was pushed out of the boreholes and shotcrete trolley at the tunnel face, the resulting sediment filled the entire to half-section of the tunnel, reaching a length of 46 m, while the tunnel cross-section was 176.625 m. 2 It belongs to the high-risk level (Level IV or Level V).

[0081] Step 3: Differentiated Response Decisions Based on Hazard Level

[0082] Based on the medium-to-high hazard level (Level III, IV, V) silt, it is necessary to calculate the critical length L1 for silt removal. If the silt length... L > L 1. Then, a segmented grouting and segmented excavation method is used to remove the silt until the critical removal length under the grouting strength is reached; if the silt length... L ≈ L 1. Full-section grouting is adopted, and deep-hole grouting is performed on the entire cross-section of the silt mass to improve the overall strength before excavation; if there is a continuous surge of mud and debris flow on site, the length of the silt mass will be affected. Lmuch smaller L In extreme cases such as type 1, a concrete grout-stopping wall is poured to seal the area, along with drainage through pressure relief holes. The ultimate thrust of the water-rich, poorly altered zone is calculated. σ s,max The critical length for cleaning is 242.805 kPa. L 1 is:

[0083]

[0084] Since this length is calculated based on the full cross-section of sediment, it will be shorter than the actual sediment after the surge, indicating that the critical length predicted by this method is relatively accurate. However, since the tunnel belongs to a high-risk level (Level IV or V), in order to ensure the safety of tunnel construction, it is recommended to use the method of sealing with a concrete grout stop wall and draining with pressure relief holes.

[0085] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for graded treatment of mudflow and sediment deposits traversing adversely altered zones, characterized in that, Includes the following steps: S10, Collect on-site information and parameters of the sudden surge disaster, including residual material scale, siltation morphology, solid component particle size, water content, water pressure conditions of the surge section and adverse geological structure type; S20, based on the information and parameters and the preset classification criteria, classify the hazard of the sediment after the mudflow surge; S30. Based on the hazard classification results, construction measures corresponding to the hazard level are adopted to treat the silt. Among them, for silt with low hazard level, direct dredging or sandbag back pressure is adopted. For silt with medium and high hazard levels, the critical length for silt removal is first calculated, and then at least one of the following methods is adopted based on the critical length: segmented grouting, segmented excavation, full-section grouting, or precast grout-stopping wall. In step S30, for silt of medium to high risk level, the critical length for silt removal is calculated. L The specific steps of 1 include: S31, Mechanical modeling of tunnels traversing adverse geological zones; S32, the water-rich adverse alteration zone is discretized into a series of nodes by the finite difference method, and the permeability is calculated based on the Laplace equation; S33, combine force analysis to calculate the reaction pressure of the weak zone, and calculate the critical reaction pressure according to the search method. ; S34, based on the critical counter pressure The critical length for clearing the silt was calculated according to the formula. L 1; where the formula is: In the formula, The diameter of the tunnel. For cohesion, The density of the sediment. It is the acceleration due to gravity. The coefficient of friction, This is the lateral pressure coefficient; The critical back pressure The calculation formula is: In the formula, The load on the triangular potential sliding zone by the weak zone at the top of the tunnel to be excavated is obtained by constructing a recursive relationship based on the force equilibrium equation of the disturbed zone and substituting it with the boundary conditions. To predict the width of the weak band; The horizontal penetration force in the triangular area in front of the front of the sudden surge; The vertical penetration force in the triangular area in front of the front of the sudden surge; It is the angle of inclination. ; It is the friction angle; The triangular area in front of the front of the sudden surge is severely affected.

2. The graded treatment method for mudflow surges and sediment deposits crossing adversely altered zones as described in claim 1, characterized in that, In step S20, the preset grading standard includes primary indicators and secondary indicators. The primary indicators include silt, adverse geological conditions, and tunnel factors. The secondary indicators corresponding to the silt include residual silt size, silt morphology, main solid components of the residual silt, density, water content, and d. 30 The particle size range, the secondary indicators corresponding to the adverse geological conditions include type, dip angle, width of adverse geological zone, fault, karst, water pressure conditions and groundwater level, and the secondary indicators corresponding to the tunnel factors include burial depth and cross-sectional area.

3. The graded treatment method for mudflow surges and sediment deposits crossing adversely altered zones as described in claim 1, characterized in that, The hazard classification results in step S20 include Level I, Level II, Level III, Level IV and Level V. The low hazard level includes Level I and Level II, and the medium and high hazard level includes Level III, Level IV and Level V.

4. The graded treatment method for mudflow surges and sediment deposits crossing adversely altered zones as described in claim 3, characterized in that, For Class I hazardous silt deposits, the direct dredging method is adopted, using loaders in conjunction with manual labor for cleaning, and following the principles of short advance and quick support.

5. The graded treatment method for mudflow surges and sediment deposits crossing adversely altered zones as described in claim 3, characterized in that, For Class II hazardous silt deposits, sandbag counterpressure measures are adopted. Specifically, sandbags are piled on the surface of the silt deposit to form a counterpressure retaining wall, and permeable hoses are buried to guide the water out. Cleaning is carried out after the pore water pressure dissipates and the soil consolidates.

6. The graded treatment method for mudflow and sediment deposits traversing adversely altered zones as described in claim 3, characterized in that, In step S30, for Class III, IV, and V hazardous silt deposits, at least one of the following methods is employed: segmented grouting, segmented excavation, full-section grouting, and sealing with a concrete grout-stopping wall, combined with drainage through pressure relief holes, and ensuring that a reserved length is maintained during the cleaning process. L Less than the critical length for cleaning the silt L 1.

7. A graded treatment system for mudflow and sediment deposits traversing adversely altered zones, characterized in that, The steps for implementing the method as described in any one of claims 1 to 6 include: The parameter acquisition module is used to collect on-site information and parameters of the sudden surge disaster. The information and parameters include residual material scale, siltation morphology, solid particle size, water content, water pressure conditions of the surge section, and adverse geological structure type. The hazard classification module is used to classify the hazard of the sediment after the mudflow based on the information and parameters and the preset classification criteria. The disposal decision module is used to generate construction disposal plans corresponding to the hazard level based on the hazard classification results. Specifically, for low hazard levels, it generates direct dredging or sandbag counterpressure plans. For medium and high hazard levels, it first calculates the critical length for silt removal and then generates disposal plans based on the critical length, including at least one of the following methods: segmented grouting, segmented excavation, full-section grouting, or precast grout-stopping walls.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the method as described in any one of claims 1 to 6.

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