Design method of slope debris flow protection system and protection system thereof

Abstract

The present application relates to the technical field of geological disaster prevention, in particular to a design method of a slope debris flow protection system adopting new anchor piles and passive protection nets and the protection system thereof. The present application obtains reasonable numbers and setting positions of anchor piles and protection nets through parameter calculation of a target slope, effectively improves the protection effect on debris flow, and provides a reliable guidance basis for the design of protection. Meanwhile, the present application adopts a combined reinforcement mode of new anchor piles, pile-board type stone retaining walls and passive protection nets, and the structure is reasonable and reliable, the protection effect is remarkable, and the construction and maintenance are easy. In addition, the protection system provided by the present application is flexible, and can be applied to different terrain conditions and various types of slope debris flow prevention projects.

Description

Technical Field

[0001] This invention relates to the field of geological disaster prevention and control technology, and in particular to a design method for a slope debris flow protection system and the protection system thereof. Background Technology

[0002] Debris flows are natural disasters caused by a mixture of loose soil and water flowing down a slope under the influence of gravity. They are characterized by their sudden onset, destructiveness, and unpredictability, easily causing severe casualties and property damage. Therefore, effective prevention and control of debris flow disasters is of great significance.

[0003] Currently, traditional methods for debris flow prevention mainly involve fixed protective measures, such as concrete retaining dams and gravity retaining walls. While these measures offer some protection against debris flows, they are insufficient for large-scale events due to their limited simplistic approach, low stability, and weak impact resistance. In recent years, more flexible protective measures, such as anchor piles and passive safety nets, have gained attention for slope debris flow disasters. Anchor piles increase the stability of the mountainside, reducing the damage caused by debris flows and providing dual protection for slope reinforcement and debris flow interception. Passive safety nets, on the other hand, slow down the flow velocity and reduce the impact force on protective measures, acting as a buffer. However, these measures still present some challenges. For example, in practical applications, how to scientifically and rationally design the quantity, distribution, and height of anchor piles and passive safety nets based on specific terrain conditions and debris flow characteristics, and how to consider the mitigating effects of both structures on the impact force of debris flows, all require further research and solutions. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems existing in the prior art and provide a design method and system for slope debris flow protection. This system combines newly constructed anchor piles with passive protective netting, rationally arranging the anchor piles and passive netting to slow down the debris flow velocity, thereby improving the protection effect. The design analysis considers the reduction of debris flow impact force by the anchor piles and passive protective netting, thus improving the stability and reliability of the protection measures. Simultaneously, by hanging materials such as discarded tires on the mountainside of the rockfall retaining wall to buffer the impact force of falling rocks, the effectiveness of the protection measures is enhanced. This invention has the advantages of simple operation, low cost, and significant effect, and is applicable to the field of slope debris flow protection.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a design method for a slope debris flow protection system, the design method comprising:

[0007] The first impact force of the debris flow is obtained based on the first and second parameters of the target slope.

[0008] The number of protective nets required under the first impact force is determined based on the load-bearing capacity of the protective nets.

[0009] The installation distance of the protective net is determined based on the number of protective nets and the first parameter;

[0010] Determine whether the second impact force after the first impact force passes through the protective net is less than the bearing capacity of the anchor pile;

[0011] If so, then the design is complete;

[0012] If not, the number of anchor piles under the second impact force shall be determined based on the bearing capacity of the anchor piles.

[0013] The anchor pile installation distance is determined based on the number of anchor piles and the second parameter to complete the design.

[0014] According to a specific implementation, in the above design method, the first parameter includes the slope length of the debris flow initiation zone, the debris flow velocity, the debris flow density, and the slope gradient, and the second parameter includes the slope length of the debris flow deposition zone.

[0015] According to a specific implementation method, in the above design method, the expression for the distance of the protective netting is:

[0016]

[0017] Where d is the distance between the protective netting and L f denoted as , where is the slope length of the debris flow initiation zone, and n is the number of protective nets.

[0018] According to a specific implementation, in the above design method, the expression for the first impact force is:

[0019]

[0020] Where, ρ w C is the density of the debris flow. f Let A be the impact coefficient of the debris flow. f Let v be the effective area of ​​the protective net, v be the velocity of the debris flow, and F be the first impact force.

[0021] According to a specific implementation method, in the above design method, the expression for the anchor pile setting distance is:

[0022]

[0023] Among them, L p Let n be the slope length of the debris flow deposition zone, t be the number of anchor piles in a single row, and n be the length of the slope.p d represents the number of anchor piles. p Set the distance for a single row of anchor piles.

[0024] According to a specific implementation method, in the above design method, the expression for the bearing capacity of the protective net is:

[0025] P f =S f T f F yf ,

[0026] Among them, S f T represents the cross-sectional area of ​​the protective netting. f F is the tensile strength coefficient of the protective netting. yf This refers to the yield strength of the protective netting.

[0027] Secondly, the present invention provides a slope debris flow protection system, the system comprising:

[0028] Anchor piles are installed in debris flow-prone areas, and the number and spacing of anchor piles are obtained using the design method described in claim 1.

[0029] A protective net is set up near the debris flow initiation area, and the number and spacing of anchor piles are obtained using the design method described in claim 1.

[0030] A rockfall barrier is installed between the anchor piles; a buffer material is installed on the mountainside of the rockfall barrier; and a flexible grid is installed on the top of the anchor piles.

[0031] According to one specific embodiment, in the above-mentioned protective system, the protective net includes a ring net, support posts, anchor blocks, upper steel wire anchor ropes, and steel wire rope anchor rods; wherein, the ring net is woven from high-strength steel wire and is fixed to the support posts through connectors, the bottom of the support posts is connected to anchor blocks, and the anchor blocks are embedded in stable strata.

[0032] According to one specific implementation, in the above-mentioned protection system, the upper steel wire anchor rope and the steel wire rope anchor rod together provide anchoring force for the ring net, and the steel wire rope anchor rod is embedded in a stable stratum.

[0033] According to one specific embodiment, in the above-mentioned protection system, the flexible grid is made of high-strength material to form a mesh structure, wherein the steel columns and grid of the flexible grid are fixed by connectors, and the steel columns are set at the top of the anchor pile and are tied and fixedly connected to the top reinforcing bars.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] This invention discloses a slope debris flow protection system and design method. By calculating the parameters of the target slope, it obtains a reasonable number and placement of anchor piles and protective nets, effectively improving the protection effect against debris flows and providing reliable guidance for the design of the protection system. Furthermore, by employing a combined reinforcement method of newly constructed anchor piles, pile-slab retaining walls, and passive protective nets, the structure is reasonable and reliable, with significant protective effects and ease of construction and maintenance. In addition, the protection system provided by this invention is highly flexible and applicable to different terrain conditions and various types of slope debris flow prevention and control projects. Attached Figure Description

[0036] The accompanying drawings, which form part of this invention, are used to aid in understanding the invention. The content provided in the drawings and their related descriptions can be used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0037] Figure 1 This is a schematic diagram illustrating the overall structure of a slope debris flow protection system;

[0038] Figure 2 This is a front view schematic diagram used to illustrate a slope debris flow protection system;

[0039] Figure 3 This is a top view diagram illustrating a slope debris flow protection system;

[0040] Figure 4 This is a side view schematic diagram used to illustrate a slope debris flow protection system;

[0041] Figure 5 This is a schematic diagram used to illustrate the newly constructed anchor piles and their top structure;

[0042] Figure 6 This is a schematic diagram used to illustrate the structure of a passive protection net;

[0043] The relevant markings in the above-mentioned attached drawings are as follows: 1-slope, 2-newly built anchor pile, 3-pile-slab retaining wall, 4-flexible grid mesh, 5-buffer material, 6-passive protection net, 7-steel column, 8-grid, 9-ring mesh, 10-support column, 11-anchor block, 12-uplift steel wire anchor rope, 13-steel wire rope anchor rod. Detailed Implementation

[0044] The present invention will now be described in further detail with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the invention to the following embodiments; all technologies implemented based on the content of the present invention fall within its scope. Before describing the invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0045] The technical solutions and features provided in the various parts of this invention, including the following description, can be combined with each other without conflict.

[0046] Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0047] The terms “comprising,” “having,” and any variations thereof in the specification, claims, and related parts of this invention are intended to cover non-exclusive inclusion.

[0048] This invention provides a design method for a slope debris flow protection system, the design method comprising:

[0049] The first impact force of the debris flow is obtained based on the first and second parameters of the target slope.

[0050] The number of protective nets required under the first impact force is determined based on the load-bearing capacity of the protective nets.

[0051] The installation distance of the protective net is determined based on the number of protective nets and the first parameter;

[0052] Determine whether the second impact force after the first impact force passes through the protective net is less than the bearing capacity of the anchor pile;

[0053] If so, then the design is complete;

[0054] If not, the number of anchor piles under the second impact force shall be determined based on the bearing capacity of the anchor piles.

[0055] The anchor pile installation distance is determined based on the number of anchor piles and the second parameter to complete the design.

[0056] The first parameter includes the slope length of the debris flow initiation zone, the debris flow velocity, the debris flow density, and the slope gradient; the second parameter includes the slope length of the debris flow deposition zone.

[0057] Specifically, the design method for a slope debris flow protection system provided in this embodiment of the invention is mainly used to determine the number and spacing of anchor piles and protective nets. Preferably, it can be implemented according to the following steps:

[0058] 1. Determine design parameters: Design parameters such as the flow velocity of the debris flow, the slope and length of the slope, and the maximum impact force of the debris flow need to be determined.

[0059] 2. Calculate the quantity and installation distance of passive protective netting: Based on the debris flow velocity and slope, calculate the impact force and kinetic energy of the debris flow. Next, based on the material strength and mesh size of the protective netting, calculate its maximum load-bearing capacity. Finally, using the impact force of the debris flow and the load-bearing capacity of the protective netting, calculate the required quantity and installation distance of the protective netting.

[0060] The impact force of a debris flow can be calculated using the following formula:

[0061]

[0062] In the formula: ρ w C is the density of the debris flow. f Let A be the impact coefficient of the debris flow. f Let v be the effective area of ​​the protective netting, and v be the velocity of the debris flow.

[0063] The kinetic energy E of a mudslide k It can be calculated using the following formula:

[0064]

[0065] In the formula: m is the mass of the debris flow.

[0066] The maximum load-bearing capacity P of the protective net f It can be calculated using the following formula:

[0067] P f =S f T f F yf ,

[0068] In the formula: S f T represents the cross-sectional area of ​​the protective netting. f F is the tensile strength coefficient of the protective netting. yf This refers to the yield strength of the protective netting.

[0069] The required number of protective nets, n, can be calculated using the following formula:

[0070]

[0071] The distance d can be calculated using the following formula:

[0072]

[0073] In the formula: L f This represents the slope length of the debris flow initiation zone.

[0074] Because passive protection nets can slow down the flow velocity and impact of debris flows, the number and spacing of anchor piles can be reduced. However, in some special cases, such as when the debris flow velocity is high or the slope is steep, anchor piles are needed to strengthen the protective measures.

[0075] Number of anchor piles n p It can be calculated using the following formula:

[0076]

[0077] In the formula: F r F represents the residual impact force of the debris flow after passing through the passive protection net, reduced by an empirical coefficient of 0.3. r =0.7F, P p n represents the bearing capacity of a single anchor pile. p This refers to the number of anchor piles.

[0078] The installation distance d of anchor piles p It can be derived from the following formula:

[0079]

[0080] In the formula: L p t represents the slope length of the debris flow deposition zone, and t represents the number of anchor piles in a single row.

[0081] This embodiment calculates the parameters of the target slope to obtain a reasonable number and placement of anchor piles and protective nets, effectively improving the protection against debris flows and providing reliable guidance for protection design. Furthermore, in actual design, the placement of anchor piles and passive protective nets should be considered collaboratively to achieve better protection. Simultaneously, adjustments need to be made based on actual geological conditions and environmental factors, such as the impact of hydrological conditions, soil type, and slope morphology on debris flows, to ensure the feasibility and effectiveness of the design.

[0082] Specifically, such as Figure 1 , 2 3, 4. A slope debris flow protection system designed according to the above design method specifically includes:

[0083] New anchor pile 2 is constructed on the front side of slope 1 and is laid out at a certain interval;

[0084] A pile-slab retaining wall 3 is set between two newly built anchor piles 2, with a buffer material 5 such as waste tires suspended on one side;

[0085] Flexible grid mesh 4 is installed at the top of the newly built anchor pile 2, which can effectively protect the safety of the area below;

[0086] Passive protective netting 6 is installed outside the top of the trench to protect against falling rocks and slow down the flow rate of debris flows.

[0087] The aforementioned newly constructed anchor piles 2, pile-slab retaining walls 3, flexible grid mesh 4, and passive protection nets 6 constitute a slope debris flow protection system.

[0088] like Figure 5 The aforementioned flexible grid 4 includes steel columns 7 and grid 8. The steel columns 7 are tied to the top steel cage of the newly built anchor pile 2. The grid 8 is made of high-strength steel wire into a cross mesh structure and is fixed to the steel columns 7 with connectors.

[0089] like Figure 6 The aforementioned passive protection net 6 includes a ring net 9, support posts 10, anchor blocks 11, upper-pull steel wire anchor ropes 12, and steel wire rope anchor rods 13. The ring net 9 is woven from high-strength steel wire and is fixed to the support posts 10 through connectors. The support posts 10 are fixedly connected to the anchor blocks 11, and the anchor blocks 11 are buried in stable strata. The upper-pull steel wire anchor ropes 12 and steel wire rope anchor rods 13 together provide anchoring force for the ring net 9, and the steel wire rope anchor rods 13 are buried in stable strata.

[0090] Multiple sets of the newly built anchor piles and passive protection nets can be set up, and the specific number and location can be determined according to the actual situation during the design.

[0091] The following example illustrates the specific process of the design method for a slope debris flow protection system according to the present invention.

[0092] (1) According to hydrogeological survey data, a certain slope is 100m long, of which the top 30m is the debris flow initiation zone, the middle 20m is the debris flow flow zone, and the bottom 50m is the debris flow deposition zone. The slope is 30° and the debris flow density is 2.5t / m³. 3 The maximum flow velocity of the debris flow is 15 m / s, the impact coefficient is taken as 0.5, the protective net material is steel wire rope with a yield strength of 300 MPa, and the mesh size is 10 cm × 10 cm.

[0093] (2) Calculate the number and installation distance of passive protection nets.

[0094] Calculate the impact force and kinetic energy of a debris flow:

[0095]

[0096]

[0097] Calculate the maximum load-bearing capacity of the protective netting:

[0098] If the wire rope diameter is 10mm and the protective netting consists of 33 high-strength wire ropes, then the cross-sectional area of ​​the protective netting is...

[0099]

[0100] Based on the tensile strength and yield strength of the wire rope, assuming a tensile strength of 0.9 and a yield strength of 300 MPa, the maximum load-bearing capacity of the protective net is:

[0101] P f =S f T f F yf =2590.5×10 -6 ×0.9×300×10 6 =699.6kN

[0102] Calculate the required number of protective nets and their installation distance:

[0103]

[0104]

[0105] Based on the above calculations, a two-level passive protection net needs to be set up, with a distance of 10m between each level.

[0106] (3) Calculate the number and spacing of anchor piles.

[0107] If the bearing capacity of a single anchor pile is 50kN, and the number of anchor piles in a single row is 5, then:

[0108]

[0109]

[0110] Based on the above calculations, four rows of anchor piles need to be installed, with a distance of 10m between each row.

[0111] This invention discloses a slope debris flow protection system that employs a combination of newly constructed anchor piles, pile-slab retaining walls, and passive protective netting for reinforcement. The system boasts a reasonable and reliable structure, significant protective effect, and ease of construction and maintenance. Furthermore, this protection system is highly flexible and applicable to various terrain conditions and types of slope debris flow prevention projects.

[0112] Based on the above implementation methods, this invention combines newly constructed anchor piles with passive protective netting to effectively slow down debris flow velocity, reduce the impact of debris flow on protective measures, and improve the protective effect. Simultaneously, the rockfall retaining wall intercepts falling rocks in the landslide area, preventing damage to the protective measures. The use of buffer materials such as used tires on the mountainside of the retaining wall buffers the impact of falling rocks, enhancing the effectiveness of the protective measures. This invention's protective system utilizes economical and practical materials and technologies, such as used tires and passive protective netting, reducing costs and enabling rapid construction. Furthermore, the long-term use of anchor piles also reduces maintenance costs. This invention's protective system can be designed and optimized according to different terrain conditions and debris flow characteristics, exhibiting flexibility and sustainability. The use of materials such as used tires also demonstrates environmental friendliness, meeting the requirements of sustainable development.

[0113] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A design method for a slope debris flow protection system, characterized in that, The design method includes The first impact force of the debris flow is obtained based on the first and second parameters of the target slope. The number of protective nets required under the first impact force is determined based on the load-bearing capacity of the protective nets. The installation distance of the protective net is determined based on the number of protective nets and the first parameter; Determine whether the second impact force after the first impact force passes through the protective net is less than the bearing capacity of the anchor pile; If so, then the design is complete; If not, the number of anchor piles under the second impact force shall be determined based on the bearing capacity of the anchor piles. The anchor pile installation distance is determined based on the number of anchor piles and the second parameter to complete the design. The expression for the distance of the protective netting is as follows: ， in, Set a distance for the protective net. The length of the slope in the debris flow initiation zone is given. The number of protective nets; The expression for the first impact force is: ， in, ρ w Debris flow density, C f denoted as the impact coefficient of debris flow. A f For the effective area of ​​the protective net, v The velocity of the debris flow. The first impact force; The expression for the bearing capacity of the protective net is: ， in, S f The cross-sectional area of ​​the protective netting. T f The tensile strength of the protective netting. F yf The yield strength of the protective netting; The expression for the number of anchor piles is: ， in, The bearing capacity of a single anchor pile. The number of anchor piles, The second impact force is reduced using an empirical coefficient of 0.

3. =0.7 ; The expression for the spacing of the anchor piles is: ， in, L p This represents the slope length of the debris flow deposition zone. t This refers to the number of anchor piles in a single row. The number of anchor piles. Set the distance for a single row of anchor piles.

2. The design method for a slope debris flow protection system according to claim 1, characterized in that, The first parameter includes the slope length of the debris flow initiation zone, the debris flow velocity, the debris flow density, and the slope gradient; the second parameter includes the slope length of the debris flow deposition zone.

3. A slope debris flow protection system, characterized in that, The system includes: Anchor piles are installed in debris flow-prone areas, and the number and spacing of anchor piles are obtained using the design method described in claim 1. A protective net is set up near the debris flow initiation area, and the number and spacing of anchor piles are obtained using the design method described in claim 1. A rockfall barrier is installed between the anchor piles; a buffer material is installed on the mountainside of the rockfall barrier; and a flexible grid is installed on the top of the anchor piles.

4. A slope debris flow protection system according to claim 3, characterized in that, The protective netting includes a ring net, support posts, anchor blocks, upper steel wire anchor ropes, and steel wire rope anchor rods; wherein, the ring netting is woven from high-strength steel wire and is fixed to the support posts by connectors, and the bottom of the support posts is connected to anchor blocks, which are embedded in stable strata.

5. A slope debris flow protection system according to claim 4, characterized in that, The upper-pulling steel wire anchor rope and the steel wire rope anchor rod together provide anchoring force for the ring net, and the steel wire rope anchor rod is embedded in the stable stratum.

6. A slope debris flow protection system according to claim 3, characterized in that, The flexible grid is made of high-strength material to form a mesh structure. The steel columns and grid of the flexible grid are fixed by connectors. The steel columns are set at the top of the anchor pile and are tied and fixed to the top steel bars.

Images