An evaluation method for the reinforcement design of a revetment engineering geotechnical mesh mat

Abstract

The present application belongs to the technical field of revetment engineering, and particularly relates to a kind of evaluation method for revetment engineering geotechnical net pad reinforcement design, including the revetment engineering for arranging geotechnical net pad The bank slope is divided into the first calculation partition above the bank full water level, the second calculation partition between the bank full water level and the design low water level and the third calculation partition below the design low water level;Then obtain the design flow rate information, wave element information, bank slope gradient information and geotechnical net pad material information of the revetment engineering, and the pressure information of the geotechnical net pad in each calculation partition in flood season and dry season, and based on the design flow rate information, wave element information, bank slope gradient information, geotechnical net pad material information and pressure information, the minimum average reinforcement pressure value required by the geotechnical net pad in each calculation partition is obtained respectively;Finally, according to the minimum average reinforcement pressure value required by the geotechnical net pad per unit area in each calculation partition, the safety and economy of the reinforcement design scheme of the geotechnical net pad of the revetment engineering is evaluated.

Description

Technical Field

[0001] This invention belongs to the field of bank protection engineering technology, specifically relating to an evaluation method for the design of geonet reinforcement for bank protection engineering. Background Technology

[0002] Geonets are mesh-like structures woven from geosynthetic materials. Their pores allow for plant growth, and the mesh structure, combined with plant roots, reinforces the topsoil. Early examples, three-dimensional vegetation nets, required only simple covering and provided strong protection against rainwater erosion, thus being widely used in soil and water conservation projects. However, due to their relatively large pores, their effectiveness is often limited when facing long-term (more than 3 days) erosion from river currents and waves, typically unable to withstand the long-term erosion and wave action of currents with velocities greater than 1.5 m / s. In recent years, new structures such as geomembranes and soil and water protection blankets have emerged in bank protection projects. These structures, by densifying or thickening the geonet, significantly increase the area coverage (generally greater than 80%) to isolate the water flow from the riverbed medium, achieving protection against water flow and waves. These have achieved good results, with some practical engineering cases demonstrating resistance to long-term erosion and wave action at speeds of 3 m / s. However, with the increase in the coverage area of ​​geonets and the more severe working conditions, the stress state of geonets has changed significantly, and their own instability and failure have become problems to be addressed. In actual engineering cases, geonets have been found to be lifted and torn. Therefore, engineering projects generally use reinforcement measures such as ballast loading or anchoring to strengthen the geonet structure.

[0003] However, due to the lack of systematic research on the stress conditions of geogrids in revetment projects and related reinforcement design methods, in the existing geogrid reinforcement designs for revetment projects, the selection of the number and arrangement of reinforcement components (including but not limited to: ballast components and anchors) and the arrangement method (e.g., but not limited to: rectangular array arrangement, linear array arrangement and diamond array arrangement), the selection of the type of reinforcement component (which determines the amount of reinforcement force that a single reinforcement component can provide), and the selection of the arrangement spacing between two adjacent reinforcement components are often determined based on engineering experience, making it difficult to achieve a balance between the economy and safety of the engineering scheme. Summary of the Invention

[0004] This invention provides an evaluation method for the design of geonet reinforcement in revetment projects. This addresses the problem that in existing geonet reinforcement designs for revetment projects, the selection of the number and arrangement of reinforcement components, the selection of component types, and the selection of the spacing between adjacent reinforcement components are often determined based on engineering experience, making it difficult to achieve a balance between the economy and safety of the engineering solution.

[0005] The technical solution adopted in this invention is: an evaluation method for the design of geonet reinforcement in revetment engineering, comprising the following steps:

[0006] Step 1: Based on the flat water level and the design low water level of the revetment project, divide the bank slope of the revetment project used for laying geonets into a first calculation zone above the flat water level, a second calculation zone between the flat water level and the design low water level, and a third calculation zone below the design low water level.

[0007] Step 2: Obtain the design flow velocity information, wave element information, bank slope ratio information, and geonet material information of the revetment project, as well as the pressure information of the geonet in each calculation zone during the flood season and dry season. Based on the design flow velocity information, wave element information, bank slope ratio information, geonet material information, and pressure information, obtain the maximum normal negative pressure value borne by the geonet in each calculation zone.

[0008] Step 3: Based on the maximum normal negative pressure value borne by the geonet in each calculation zone, obtain the minimum average reinforcement pressure value required for the geonet in each calculation zone.

[0009] Step 4: Based on the minimum average reinforcement pressure required per unit area of ​​the geonet in each calculation zone, verify the reinforcement design scheme of the geonet for the revetment project to evaluate the safety and economy of the geonet reinforcement design scheme for the revetment project.

[0010] Since the area of ​​the geogrid above the floodplain water level is only affected by water flow and waves during the flood season, the area between the floodplain water level and the design low water level is affected by water flow and waves during both the flood and low water seasons, while the area below the design low water level is mainly affected by water flow during both the flood and low water seasons, the pressure conditions of the three areas of the geogrid often differ significantly. In the evaluation method for geogrid reinforcement design of revetment engineering provided by this invention, the bank slope used to lay the geogrid is divided into a first calculation zone, a second calculation zone, and a third calculation zone to correspond to the three areas respectively. By performing pressure analysis on the geogrid located in each of the three calculation zones, the pressure of the geogrid in each calculation zone is obtained. By combining the pressure information during the flood and dry seasons with the design flow velocity, wave element, bank slope ratio, and geogrid material information of the revetment project, the maximum normal negative pressure value borne by the geogrid in each calculation zone is obtained. Then, based on the maximum normal negative pressure value borne by the geogrid in each calculation zone, the minimum average reinforcement pressure value required for the geogrid in each calculation zone is obtained. Finally, based on the minimum average reinforcement pressure value required per unit area of ​​geogrid in each calculation zone, the reinforcement design scheme of the geogrid for the revetment project is verified (by comparing the minimum average reinforcement pressure value required per unit area of ​​geogrid in each calculation zone with the design average reinforcement pressure value provided by the reinforcement components to the geogrid in each calculation zone). This allows for the evaluation of the safety and economy of the geogrid reinforcement design scheme for the revetment project.

[0011] Furthermore, in step 1, if the first design water level of the bank protection project is above the flat beach water level, then the first calculation zone is divided into a first sub-calculation zone above the first design water level and a second sub-calculation zone between the first design water level and the flat beach water level, based on the first design water level.

[0012] Since the geogrid within the first calculation partition can typically be divided from top to bottom into an area where only the wave impact during the flood season needs to be considered (i.e., the area above the first design water level) and an area where the water flow and wave impact during the flood season needs to be considered (i.e., the area between the first design water level and the flat water level), the pressure conditions of the geogrid in these two areas often differ. By dividing the first calculation partition into a first sub-calculation partition and a second sub-calculation partition to correspond to the two areas respectively, and by performing pressure analysis on the geogrid located in the first sub-calculation partition and the second sub-calculation partition respectively, the pressure information of the geogrid in the first sub-calculation partition and the second sub-calculation partition during the flood season and the dry season can be obtained. This information can then be combined with the bank protection work... Based on the design flow velocity information, wave element information, bank slope ratio information, and geonet material information of the project, the maximum normal negative pressure value borne by the geonet in the first sub-calculation zone and the second sub-calculation zone is obtained respectively. Then, based on the maximum normal negative pressure value borne by the geonet in the first sub-calculation zone and the second sub-calculation zone, the minimum average reinforcement pressure value required for the geonet in the first sub-calculation zone and the second sub-calculation zone is obtained respectively. This makes the evaluation of the reinforcement design of the geonet in the first calculation zone more targeted and accurate when verifying the reinforcement design scheme of the geonet in the revetment project. This allows the evaluation method of geonet reinforcement design for revetment projects provided by this invention to more accurately evaluate the safety and economy of the geonet reinforcement design scheme for revetment projects.

[0013] Furthermore, the first design water level is any design flood level between the five-year return period design flood level and the ten-year return period design flood level of the bank protection project.

[0014] When the five-year flood level of the revetment project is above the flat beach water level, the first design water level is set to any design flood level between the five-year and ten-year design flood levels of the revetment project. This also meets the requirement that geogrids in the area above the first design water level generally do not need to consider the influence of water flow and waves during the flood season, while geogrids in the area between the first design water level and the flat beach water level need to consider the influence of water flow and waves during the flood season.

[0015] Furthermore, in step 1, if the second design water level of the bank protection project is located between the flat water level and the design low water level, then the second calculation zone is divided into a third sub-calculation zone between the flat water level and the second design water level, and a fourth sub-calculation zone between the second design water level and the design low water level, based on the second design water level.

[0016] Since the geogrid in the second calculation partition can usually be divided from top to bottom into areas that only need to consider the impact of water flow and waves during the flood season (i.e., the area between the flat water level and the second design water level), and areas that need to consider the impact of water flow and waves during the flood season and the impact of water flow and waves during the dry season (i.e., the area between the second design water level and the design low water level), the pressure conditions of the geogrid in these two areas often differ. By dividing the second calculation partition into the third sub-calculation partition and the fourth sub-calculation partition to correspond to the two areas respectively, and by performing pressure analysis on the geogrid in the third sub-calculation partition and the fourth sub-calculation partition respectively, the pressure conditions of the geogrid in the third sub-calculation partition and the fourth sub-calculation partition during the flood season and the dry season can be obtained. By combining the pressure information with the design flow velocity information, wave element information, bank slope ratio information, and geonet material information of the revetment project, the maximum normal negative pressure value borne by the geonet in the third and fourth sub-calculation zones is obtained respectively. Furthermore, based on the maximum normal negative pressure value borne by the geonet in the third and fourth sub-calculation zones, the minimum average reinforcement pressure value required for the geonet in the third and fourth sub-calculation zones is obtained respectively. This allows for a more targeted and accurate evaluation of the reinforcement design of the geonet in the second calculation zone when verifying the reinforcement design scheme of the geonet in the revetment project. This enables the evaluation method for the geonet reinforcement design of revetment projects provided by this invention to more accurately assess the safety and economy of the geonet reinforcement design scheme for revetment projects.

[0017] Furthermore, the second design water level is the design flood level for a two-year return period of the bank protection project.

[0018] When the design flood level for a two-year return period of the bank protection project is located between the plain water level and the design low water level, the second design water level is set as the design flood level for a two-year return period of the bank protection project; the geogrid in the area between the plain water level and the second design water level only needs to consider the influence of water flow and waves during the flood season, while the geogrid in the area between the second design water level and the design low water level needs to consider the influence of water flow and waves during both the flood season and the low water season.

[0019] Furthermore, in step 2, the pressure information includes: the maximum normal negative pressure borne by the geonet in the first calculation zone is the normal negative pressure borne by the geonet in the first calculation zone during the flood season; the maximum normal negative pressure borne by the geonet in the second calculation zone is the larger of the normal negative pressure borne by the geonet in the second calculation zone during the flood season and the normal negative pressure borne by the geonet in the second calculation zone during the dry season; the maximum normal negative pressure borne by the geonet in the third calculation zone is the normal negative pressure borne by the geonet in the third calculation zone during the flood season.

[0020] In step 3, the minimum average reinforcement pressure required for the geonet in the first calculation zone is equal to the maximum normal negative pressure borne by the geonet in the first calculation zone; the minimum average reinforcement pressure required for the geonet in the second calculation zone is equal to the maximum normal negative pressure borne by the geonet in the second calculation zone; and the minimum average reinforcement pressure required for the geonet in the third calculation zone is equal to the maximum normal negative pressure borne by the geonet in the third calculation zone.

[0021] Furthermore, the normal negative pressure value borne by the geonet in each calculation zone during the flood season is calculated using the following formula:

[0022] P t =PW t +PB t +PD t , t∈(1、2)

[0023] P t =PB t +PD t t=3

[0024] Where t is the index of the computation partition; P t PW represents the normal negative pressure value borne by the geonet in the t-th calculation zone during the flood season. t denoted as PBt, it represents the normal wave negative pressure value borne by the geonet in the t-th calculation zone during the flood season; PBt represents the normal buoyancy pressure value borne by the geonet in the t-th calculation zone during the flood season; PD t Let be the normal hydrodynamic negative pressure value borne by the geonet in the t-th calculation zone during the flood season;

[0025] The normal negative pressure borne by the geonet in the second calculation zone during the dry season is calculated using the following formula:

[0026] P′2=PW′2+PB′2+PD′2

[0027] Wherein, P′2 is the normal negative pressure value borne by the geonet in the second calculation zone during the dry season; PW′2 is the normal wave negative pressure value borne by the geonet in the second calculation zone during the dry season; PB′2 is the normal buoyancy pressure value borne by the geonet in the second calculation zone during the dry season; and PD′2 is the normal dynamic water negative pressure value borne by the geonet in the second calculation zone during the dry season.

[0028] Furthermore, the normal wave negative pressure value borne by the geogrid in each calculation zone during the flood season is calculated using the following formula:

[0029]

[0030] Where α is the first empirical coefficient; γ w H1 is the unit weight of water; L1 is the design wave height of the revetment project during the flood season; L1 is the design wavelength of the revetment project during the flood season; B is the length of a single geonet along the slope inclination direction.

[0031] The value of the first experience system is 0.8.

[0032] Furthermore, the normal buoyancy pressure borne by the geonet in each calculation zone during the flood season is calculated using the following formula:

[0033]

[0034] Where, γ w γ is the specific weight of water; c d is the unit weight of the geonet; d is the thickness of the geonet; m t Calculate the slope ratio of the bank slope in the t-th partition.

[0035] Furthermore, the normal hydrodynamic negative pressure value borne by the geonet in each calculation zone during the flood season is calculated using the following formula:

[0036]

[0037] Where δ is the reduction factor; ρ w V1 is the density of water; V0 is the design flow velocity of water flowing outside the geogrid of the revetment during the flood season; V1 is the design flow velocity of water flowing inside the geogrid of the revetment during the flood season; m t Calculate the slope ratio of the bank slope in the t-th partition.

[0038] The reduction factor ranges from 0.025 to 0.25.

[0039] Furthermore, the normal wave negative pressure value borne by the geonet in the second calculation zone during the dry season is calculated using the following formula:

[0040]

[0041] Where α is the first empirical coefficient; γ w H2 is the unit weight of water; L2 is the design wave height of the revetment project during the dry season; L2 is the design wavelength of the revetment project during the dry season; B is the length of a single geonet along the slope inclination direction.

[0042] Furthermore, the normal buoyancy pressure borne by the geonet in the second calculation zone during the dry season is calculated using the following formula:

[0043]

[0044] Where, γ w γ is the specific weight of water; c d is the unit weight of the geonet; d is the thickness of the geonet; m2 is the slope ratio of the bank in the second calculation zone.

[0045] Furthermore, the normal hydrodynamic negative pressure value borne by the geonet in the second calculation zone during the flood season is calculated using the following formula:

[0046]

[0047] Where δ is the reduction factor; ρ w V1 is the density of water; V2 is the design flow velocity of the water flow outside the geonet of the revetment during the dry season; V3 is the design flow velocity of the water flow inside the geonet of the revetment during the dry season; m2 is the slope ratio of the bank in the second calculation zone.

[0048] Furthermore, the method for verifying the reinforcement design scheme of the geonet mattress for the revetment project includes the following sub-steps:

[0049] S401: Obtain the design value of the reinforcement pressure of the geonet in each calculation zone of the reinforcement design scheme of the geonet;

[0050] S402: Perform a safety assessment of the geonet reinforcement design scheme for the revetment project. If the design reinforcement pressure of the geonet in each calculation zone of the geonet reinforcement design scheme is greater than the minimum average reinforcement pressure required by the geonet in the corresponding calculation zone, then the safety of the geonet reinforcement design scheme for the revetment project is deemed qualified, and proceed to sub-step S403; otherwise, the safety of the geonet reinforcement design scheme for the revetment project is deemed unqualified.

[0051] S403: Perform an economic evaluation of the geonet reinforcement design scheme for the revetment project. If the difference between the design reinforcement pressure of the geonet in each calculation zone and the minimum average reinforcement pressure required by the geonet in the corresponding calculation zone is less than the preset error value, then the economic evaluation of the geonet reinforcement design scheme for the revetment project is deemed qualified; otherwise, the economic evaluation of the geonet reinforcement design scheme for the revetment project is deemed unqualified.

[0052] Furthermore, in the reinforcement design scheme of the geonet, the design value of the reinforcement pressure of the geonet in each calculation zone is calculated using the following formula:

[0053]

[0054] Where t is the index of the computation partition; P″ t T represents the design reinforcement pressure of the geonet in the t-th calculation zone; t The normal reinforcement force provided by μ to a single reinforcement member on the geonet in the t-th computational partition; t β is the second empirical coefficient. t Let be the average area of ​​the geonet reinforced by each reinforcement member in the t-th calculation partition.

[0055] Preferably, at t=1, μ t =0.6; at t=2, μ t =0.9; at t=3, μ t =1.2.

[0056] When each reinforcement component in each calculation partition is arranged in a rectangular array, the average area of ​​the geonet reinforced by each reinforcement component in each calculation partition is the total area of ​​the geonet in that calculation partition divided by the number of reinforcement components in that calculation partition. Attached Figure Description

[0057] Figure 1 This is a flowchart illustrating the evaluation method for the geonet reinforcement design of the revetment project in the embodiment.

[0058] Figure 2 This is a schematic diagram of the calculation zoning of the bank slope used for arranging geonets in the embodiment;

[0059] Among them, 1—plain water level, 2—design low water level, 3—first design water level, 4—second design water level, 5—first calculation zone, 6—second calculation zone, 7—third calculation zone;

[0060] 51—First sub-computation partition; 52—Second sub-computation partition;

[0061] 61—Third sub-computation partition, 62—Fourth sub-computation partition. Detailed Implementation

[0062] The technical solutions of the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings:

[0063] like Figure 1 and Figure 2 As shown in the figure, this embodiment provides an evaluation method for the design of geonet reinforcement for revetment projects, including the following steps:

[0064] Step 1: Based on the flat water level 1 and the design low water level 2 of the revetment project, the bank slope used for laying geonet mattresses in the revetment project is divided into the first calculation zone 5 above the flat water level 1, the second calculation zone 6 between the flat water level 1 and the design low water level 2, and the third calculation zone 7 below the design low water level 2.

[0065] Step 2: Obtain the design flow velocity information, wave element information, bank slope ratio information, and geonet material information of the revetment project, as well as the pressure information of the geonet in each calculation zone during the flood season and dry season. Based on the design flow velocity information, wave element information, bank slope ratio information, geonet material information, and pressure information, obtain the maximum normal negative pressure value borne by the geonet in each calculation zone.

[0066] Step 3: Based on the maximum normal negative pressure value borne by the geonet in each calculation zone, obtain the minimum average reinforcement pressure value required for the geonet in each calculation zone.

[0067] Step 4: Based on the minimum average reinforcement pressure required per unit area of ​​geonet in each calculation zone, verify the reinforcement design scheme of geonet for the revetment project to evaluate the safety and economy of the geonet reinforcement design scheme for the revetment project.

[0068] Since the area of ​​the geogrid above the floodplain water level 1 is only affected by water flow and waves during the flood season, the area between the floodplain water level 1 and the design low water level 2 is affected by water flow and waves during both the flood and low water seasons, while the area below the design low water level 2 is mainly affected by water flow during both the flood and low water seasons, the pressure conditions of the geogrid in these three areas often differ significantly. In the evaluation method for geogrid reinforcement design of revetment projects provided by this invention, the bank slope used for laying the geogrid is divided into a first calculation zone 5, a second calculation zone 6, and a third calculation zone 7, corresponding to the three areas respectively. By performing pressure analysis on the geogrids located in the three calculation zones, the pressure conditions of the geogrids in each calculation zone during the flood and low water seasons are obtained. By combining the pressure information with the design flow velocity, wave element information, bank slope ratio information, and geonet material information of the revetment project, the maximum normal negative pressure value borne by the geonet in each calculation zone is obtained. Then, based on the maximum normal negative pressure value borne by the geonet in each calculation zone, the minimum average reinforcement pressure value required for the geonet in each calculation zone is obtained. Finally, based on the minimum average reinforcement pressure value required per unit area of ​​geonet in each calculation zone, the reinforcement design scheme of the geonet for the revetment project is verified (by comparing the minimum average reinforcement pressure value required per unit area of ​​geonet in each calculation zone with the design average reinforcement pressure value provided by the reinforcement components to the geonet in each calculation zone). The safety and economy of the geonet reinforcement design scheme for the revetment project can then be evaluated.

[0069] Specifically, in step 2, the pressure information includes: the maximum normal negative pressure borne by the geonet in the first calculation zone 5 is the normal negative pressure borne by the geonet in the first calculation zone 5 during the flood season; the maximum normal negative pressure borne by the geonet in the second calculation zone 6 is the larger of the two normal negative pressures: the normal negative pressure borne by the geonet in the second calculation zone 6 during the flood season and the normal negative pressure borne by the geonet in the second calculation zone 6 during the dry season; the maximum normal negative pressure borne by the geonet in the third calculation zone 7 is the normal negative pressure borne by the geonet in the third calculation zone 7 during the flood season.

[0070] In step 3, the minimum average reinforcement pressure required for the geonet in the first calculation zone 5 is equal to the maximum normal negative pressure borne by the geonet in the first calculation zone 5; the minimum average reinforcement pressure required for the geonet in the second calculation zone 6 is equal to the maximum normal negative pressure borne by the geonet in the second calculation zone 6; and the minimum average reinforcement pressure required for the geonet in the third calculation zone 7 is equal to the maximum normal negative pressure borne by the geonet in the third calculation zone 7.

[0071] In this embodiment, the normal negative pressure value borne by the geonet in each calculation zone during the flood season is calculated using the following formula:

[0072] P t =PW t +PB t +PD t , t∈(1、2)

[0073] P t =PB t +PD t t=3

[0074] Where t is the index of the computation partition; P t PW represents the normal negative pressure value borne by the geonet in the t-th calculation zone during the flood season. t PB represents the normal wave negative pressure value borne by the geonet in the t-th calculation zone during the flood season; t PD represents the normal buoyancy pressure exerted on the geonet in the t-th calculation zone during the flood season. t Let be the normal hydrodynamic negative pressure value borne by the geonet in the t-th calculation zone during the flood season;

[0075] The normal negative pressure value borne by the geonet in the second calculation zone 6 during the dry season is calculated using the following formula:

[0076] P′2=PW′2+PB′2+PD′2

[0077] Wherein, P′2 is the normal negative pressure value borne by the geonet in the second calculation zone 6 during the dry season; PW′2 is the normal wave negative pressure value borne by the geonet in the second calculation zone 6 during the dry season; PB′2 is the normal buoyancy pressure value borne by the geonet in the second calculation zone 6 during the dry season; and PD′2 is the normal dynamic water negative pressure value borne by the geonet in the second calculation zone 6 during the dry season.

[0078] In this calculation, the geonet in any calculation zone is affected by water flow, that is, the geonet in that calculation zone will be subjected to the normal buoyancy pressure and normal hydrodynamic negative pressure exerted by the water flow; the geonet in any calculation zone is affected by waves, that is, the geonet in that calculation zone will be subjected to the normal wave negative pressure exerted by the waves.

[0079] In this embodiment, the normal wave negative pressure value borne by the geonet in each calculation zone during the flood season is calculated using the following formula:

[0080]

[0081] Where α is the first empirical coefficient; γ wH1 is the unit weight of water; L1 is the design wave height of the revetment project during the flood season; L1 is the design wavelength of the revetment project during the flood season; B is the length of a single geonet along the slope inclination direction.

[0082] The value of the first empirical system is 0.8.

[0083] In this embodiment, the normal buoyancy pressure borne by the geonet in each calculation zone during the flood season is calculated using the following formula:

[0084]

[0085] Where, γ w γ is the specific weight of water; c d is the unit weight of the geonet; d is the thickness of the geonet; m t Calculate the slope ratio of the bank slope in the t-th partition.

[0086] In this embodiment, the normal hydrodynamic negative pressure value borne by the geonet in each calculation zone during the flood season is calculated using the following formula:

[0087]

[0088] Where δ is the reduction factor; ρ w V1 is the density of water; V2 is the design velocity of the water flow outside the geonet of the revetment during the flood season; V3 is the design velocity of the water flow inside the geonet of the revetment during the flood season; m t Calculate the slope ratio of the bank slope in the t-th partition.

[0089] The reduction factor ranges from 0.025 to 0.25.

[0090] In this embodiment, the normal wave negative pressure value borne by the geonet in the second calculation zone 6 during the dry season is calculated using the following formula:

[0091]

[0092] Where α is the first empirical coefficient; γ w H2 is the unit weight of water; L2 is the design wave height of the revetment project during the dry season; L2 is the design wavelength of the revetment project during the dry season; B is the length of a single geonet along the slope inclination direction.

[0093] In this embodiment, the normal buoyancy pressure borne by the geonet in the second calculation zone 6 during the dry season is calculated using the following formula:

[0094]

[0095] Where, γ w γ is the specific weight of water;c d is the unit weight of the geonet; d is the thickness of the geonet; m2 is the slope ratio of the bank in the second calculation zone 6.

[0096] In this embodiment, the normal hydrodynamic negative pressure value borne by the geonet in the second calculation zone 6 during the flood season is calculated using the following formula:

[0097]

[0098] Where δ is the reduction factor; ρ w V1 is the density of water; V2 is the design flow velocity of water flowing outside the geonet of the revetment during the dry season; V3 is the design flow velocity of water flowing inside the geonet of the revetment during the dry season; m2 is the slope ratio of the bank in the second calculation zone 6.

[0099] Specifically, in this embodiment, the method for verifying the reinforcement design scheme of the geonet for the revetment project includes the following sub-steps:

[0100] S401: Obtain the design value of the reinforcement pressure of the geonet in each calculation zone of the reinforcement design scheme of the geonet;

[0101] S402: Determine the safety of the geonet reinforcement design scheme for the revetment project. If the reinforcement pressure design value of the geonet in each calculation zone of the geonet reinforcement design scheme is greater than the minimum average reinforcement pressure value required by the geonet in the corresponding calculation zone, then the safety of the geonet reinforcement design scheme for the revetment project is deemed qualified, and proceed to sub-step S403; otherwise, the safety of the geonet reinforcement design scheme for the revetment project is deemed unqualified.

[0102] S403: The economic feasibility of the geogrid reinforcement design scheme for the revetment project is judged as follows: if the difference between the design value of the reinforcement pressure of the geogrid in each calculation zone and the minimum average reinforcement pressure value required by the geogrid in the corresponding calculation zone is less than the preset error value, then the economic feasibility of the geogrid reinforcement design scheme for the revetment project is deemed qualified; otherwise, the economic feasibility of the geogrid reinforcement design scheme for the revetment project is deemed unqualified.

[0103] Specifically, in this embodiment, the design value of the reinforcement pressure of the geonet in each calculation zone of the geonet reinforcement design scheme is calculated using the following formula:

[0104]

[0105] Where t is the index of the computation partition; P″ t T represents the design reinforcement pressure of the geonet in the t-th calculation zone; tThe normal reinforcement force provided by a single reinforcement member on the geonet in the t-th calculation partition; μt is the second empirical coefficient, β t Let be the average area of ​​the geonet reinforced by each reinforcement member in the t-th calculation partition.

[0106] Preferably, at t=1, μ t =0.6; at t=2, μ t =0.9; at t=3, μ t =1.2.

[0107] When each reinforcement component in each calculation partition is arranged in a rectangular array, the average area of ​​the geonet reinforced by each reinforcement component in each calculation partition is the total area of ​​the geonet in that calculation partition divided by the number of reinforcement components in that calculation partition.

[0108] Preferably, in step 1, if the first design water level 3 of the bank protection project is above the beach water level 1, then the first calculation zone 5 is divided into a first sub-calculation zone 51 above the first design water level 3 and a second sub-calculation zone 52 between the first design water level 3 and the beach water level 1 according to the first design water level 3.

[0109] Since the geogrid mats within the first calculation zone 5 can typically be divided from top to bottom into an area where only the wave impact during the flood season needs to be considered (i.e., the area above the first design water level 3), and an area where the water flow and wave impact during the flood season needs to be considered (i.e., the area between the first design water level 3 and the flat water level 1), the pressure conditions of these two areas of the geogrid mats often differ. By dividing the first calculation zone 5 into a first sub-calculation zone 51 and a second sub-calculation zone 52 to correspond to the two areas respectively, and by performing pressure analysis on the geogrid mats located in the first sub-calculation zone 51 and the second sub-calculation zone 52 respectively, the pressure information of the geogrid mats in the first sub-calculation zone 51 and the second sub-calculation zone 52 during the flood season and the dry season can be obtained. This information can then be combined with the design of the revetment project. By using flow velocity information, wave element information, bank slope ratio information, and geonet material information, the maximum normal negative pressure value borne by the geonet in the first sub-calculation partition 51 and the second sub-calculation partition 52 is obtained. Furthermore, based on the maximum normal negative pressure value borne by the geonet in the first sub-calculation partition 51 and the second sub-calculation partition 52, the minimum average reinforcement pressure value required for the geonet in the first sub-calculation partition 51 and the second sub-calculation partition 52 is obtained. This allows for a more targeted and accurate evaluation of the reinforcement design of the geonet in the first calculation partition 5 when verifying the reinforcement design scheme of the geonet in the revetment project. This enables the evaluation method for the geonet reinforcement design of the revetment project provided by this invention to more accurately assess the safety and economy of the geonet reinforcement design scheme for the revetment project.

[0110] The pressure information also includes: the maximum normal negative pressure borne by the geonet in the first sub-calculation partition 51 is the normal negative pressure borne by the geonet in the first sub-calculation partition 51 during the flood season; the maximum normal negative pressure borne by the geonet in the second sub-calculation partition 52 is the normal negative pressure borne by the geonet in the second sub-calculation partition 52 during the flood season.

[0111] Among them, the geogrid in the first sub-calculation partition 51 only needs to consider the wave impact during the flood season, while the geogrid in the second sub-calculation partition 52 needs to consider the water flow and wave impact during the flood season.

[0112] Specifically, in this embodiment, the first design water level 3 is any design flood level between the five-year return period design flood level and the ten-year return period design flood level of the bank protection project.

[0113] When the five-year flood level of the revetment project is above the beach level 1, the first design water level 3 is set as any design flood level between the five-year and ten-year design flood levels of the revetment project. This also meets the requirement that geogrids in the area above the first design water level 3 usually do not need to consider the influence of water flow and waves during the flood season, while geogrids in the area between the first design water level 3 and the beach level 1 need to consider the influence of water flow and waves during the flood season.

[0114] Preferably, in step 1, if the second design water level 4 of the bank protection project is located between the beach water level 1 and the design low water level 2, then the second calculation zone 6 is divided into a third sub-calculation zone 61 between the beach water level 1 and the second design water level 4, and a fourth sub-calculation zone 62 between the second design water level 4 and the design low water level 2, according to the second design water level 4.

[0115] Since the geogrid mats within the second calculation partition 6 can typically be divided from top to bottom into areas where only the effects of water flow and waves during the flood season need to be considered (i.e., the area between the floodplain level 1 and the second design water level 4), and areas where the effects of water flow and waves during the flood season and the dry season need to be considered simultaneously (i.e., the area between the second design water level 4 and the design low water level 2), the pressure conditions of the geogrid mats in these two areas often differ. By dividing the second calculation partition 6 into a third sub-calculation partition 61 and a fourth sub-calculation partition 62 to correspond to the two areas respectively, and by performing pressure analysis on the geogrid mats located in the third sub-calculation partition 61 and the fourth sub-calculation partition 62 respectively, the pressure information of the geogrid mats in the third sub-calculation partition 61 and the fourth sub-calculation partition 62 during the flood season and the dry season can be obtained. Based on the information, combined with the design flow velocity, wave element information, bank slope ratio information, and geonet material information of the revetment project, the maximum normal negative pressure value borne by the geonet in the third sub-calculation partition 61 and the fourth sub-calculation partition 62 is obtained. Then, based on the maximum normal negative pressure value borne by the geonet in the third sub-calculation partition 61 and the fourth sub-calculation partition 62, the minimum average reinforcement pressure value required for the geonet in the third sub-calculation partition 61 and the fourth sub-calculation partition 62 is obtained. This makes the evaluation of the reinforcement design of the geonet in the second calculation partition 6 more targeted and accurate when verifying the reinforcement design scheme of the geonet in the revetment project. This allows the evaluation method of geonet reinforcement design for revetment projects provided by this invention to more accurately evaluate the safety and economy of the geonet reinforcement design scheme for revetment projects.

[0116] The pressure information also includes: the maximum normal negative pressure borne by the geonet in the third sub-calculation partition 61 is the normal negative pressure borne by the geonet in the third sub-calculation partition 61 during the flood season; the maximum normal negative pressure borne by the geonet in the fourth sub-calculation partition 62 is the larger of the two normal negative pressures: the normal negative pressure borne by the geonet in the fourth sub-calculation partition 62 during the flood season and the normal negative pressure borne by the geonet during the dry season.

[0117] Among them, the geogrid in the third sub-calculation partition 61 only needs to consider the influence of water flow and waves during the flood season, while the geogrid in the fourth sub-calculation partition 62 needs to consider the influence of water flow and waves during the flood season as well as the influence of water flow and waves during the dry season.

[0118] Specifically, in this embodiment, the second design water level 4 is the design flood level for the bank protection project that occurs once every two years.

[0119] When the design flood level for a two-year return period of the bank protection project is located between the plain water level 1 and the design low water level 2, the second design water level 4 is set as the design flood level for a two-year return period of the bank protection project. The geogrid in the area between the plain water level 1 and the second design water level 4 only needs to consider the influence of water flow and waves during the flood season. The geogrid in the area between the second design water level 4 and the design low water level 2 needs to consider the influence of water flow and waves during both the flood season and the low water season.

[0120] The evaluation method for the design of geonet reinforcement for bank protection engineering provided by this invention has at least the following technical effects or advantages:

[0121] 1. Since the area of ​​the geogrid above the floodplain water level 1 is only affected by water flow and waves during the flood season, the area between the floodplain water level 1 and the design low water level 2 is affected by water flow and waves during both the flood season and the low water season, while the area below the design low water level 2 is mainly affected by water flow during both the flood season and the low water season, the pressure conditions of the geogrid in these three areas often differ significantly. In the evaluation method for geogrid reinforcement design of revetment projects provided by this invention, the bank slope used for laying the geogrid is divided into a first calculation zone 5, a second calculation zone 6, and a third calculation zone 7 to correspond to the three areas mentioned above, and the pressure analysis of the geogrid in each of the three calculation zones is performed to obtain the pressure conditions of the geogrid in each calculation zone during the flood season and the low water season. By combining the pressure information of the period with the design flow velocity information, wave element information, bank slope ratio information, and geonet material information of the revetment project, the maximum normal negative pressure value borne by the geonet in each calculation zone is obtained. Then, based on the maximum normal negative pressure value borne by the geonet in each calculation zone, the minimum average reinforcement pressure value required for the geonet in each calculation zone is obtained. Finally, based on the minimum average reinforcement pressure value required per unit area of ​​geonet in each calculation zone, the reinforcement design scheme of the geonet for the revetment project is verified (by comparing the minimum average reinforcement pressure value required per unit area of ​​geonet in each calculation zone with the design average reinforcement pressure value provided by the reinforcement components to the geonet in each calculation zone in each calculation zone), the safety and economy of the geonet reinforcement design scheme for the revetment project can be evaluated.

[0122] 2. Since the geogrid in the first calculation zone 5 can usually be divided from top to bottom into an area where only the wave impact during the flood season needs to be considered (i.e., the area above the first design water level 3), and an area where the water flow and wave impact during the flood season needs to be considered (i.e., the area between the first design water level 3 and the flat water level 1), the pressure conditions of the geogrid in these two areas often differ. By dividing the first calculation zone 5 into a first sub-calculation zone 51 and a second sub-calculation zone 52 to correspond to the two areas respectively, and by performing pressure analysis on the geogrids located in the first sub-calculation zone 51 and the second sub-calculation zone 52 respectively, the pressure information of the geogrids in the first sub-calculation zone 51 and the second sub-calculation zone 52 during the flood season and the dry season can be obtained. This information can then be combined with the design of the revetment project. By collecting flow velocity information, wave element information, bank slope ratio information, and geonet material information, the maximum normal negative pressure value borne by the geonet in the first sub-calculation partition 51 and the second sub-calculation partition 52 is obtained. Then, based on the maximum normal negative pressure value borne by the geonet in the first sub-calculation partition 51 and the second sub-calculation partition 52, the minimum average reinforcement pressure value required for the geonet in the first sub-calculation partition 51 and the second sub-calculation partition 52 is obtained. This allows for a more targeted and accurate evaluation of the reinforcement design of the geonet in the first calculation partition 5 when verifying the geonet reinforcement design scheme for bank protection projects. This enables the evaluation method for geonet reinforcement design in bank protection projects provided by this invention to more accurately assess the safety and economy of geonet reinforcement design schemes for bank protection projects.

[0123] 3. When the five-year flood level of the revetment project is above the beach level 1, the first design water level 3 is set as any design flood level between the five-year and ten-year design flood levels of the revetment project. This also meets the requirement that geogrids in the area above the first design water level 3 usually do not need to consider the influence of water flow and waves during the flood season, while geogrids in the area between the first design water level 3 and the beach level 1 need to consider the influence of water flow and waves during the flood season.

[0124] 4. Since the geonets within the second calculation zone 6 can typically be divided from top to bottom into areas where only the effects of water flow and waves during the flood season need to be considered (i.e., the area between the floodplain water level 1 and the second design water level 4), and areas where the effects of water flow and waves during the flood season and the dry season need to be considered simultaneously (i.e., the area between the second design water level 4 and the design low water level 2), the compression conditions of the geonets in these two areas often differ. By dividing the second calculation zone 6 into a third sub-calculation zone 61 and a fourth sub-calculation zone 62 to correspond to the two areas respectively, and by performing compression analysis on the geonets located in the third sub-calculation zone 61 and the fourth sub-calculation zone 62 respectively, the compression conditions of the geonets in the third sub-calculation zone 61 and the fourth sub-calculation zone 62 during the flood season and the dry season can be obtained. By combining the information with the design flow velocity, wave element, bank slope ratio, and geonet material information of the revetment project, the maximum normal negative pressure value borne by the geonet in the third sub-calculation partition 61 and the fourth sub-calculation partition 62 is obtained. Furthermore, based on the maximum normal negative pressure value borne by the geonet in the third sub-calculation partition 61 and the fourth sub-calculation partition 62, the minimum average reinforcement pressure value required for the geonet in the third sub-calculation partition 61 and the fourth sub-calculation partition 62 is obtained. This allows for a more targeted and accurate evaluation of the reinforcement design of the geonet in the second calculation partition 6 when verifying the geonet reinforcement design scheme of the revetment project. This enables the evaluation method for geonet reinforcement design of revetment projects provided by this invention to more accurately assess the safety and economy of the geonet reinforcement design scheme for revetment projects.

[0125] 5. When the design flood level for a two-year return period of the bank protection project is located between the plain water level 1 and the design low water level 2, the second design water level 4 shall be set as the design flood level for a two-year return period of the bank protection project. The geogrid in the area between the plain water level 1 and the second design water level 4 only needs to consider the influence of water flow and waves during the flood season. The geogrid in the area between the second design water level 4 and the design low water level 2 needs to consider the influence of water flow and waves during both the flood season and the low water season.

[0126] The above are merely specific application examples of the present invention and do not constitute any limitation on the scope of protection of the present invention. All technical solutions formed by equivalent transformation or equivalent substitution fall within the scope of protection of the present invention.

Claims

1. An evaluation method for the design of geonet reinforcement in revetment engineering, characterized in that, Includes the following steps: Step 1: Based on the flat water level and the design low water level of the revetment project, divide the bank slope of the revetment project used for laying geonets into a first calculation zone above the flat water level, a second calculation zone between the flat water level and the design low water level, and a third calculation zone below the design low water level. Step 2: Obtain the design flow velocity information, wave element information, bank slope ratio information, and geonet material information of the revetment project, as well as the pressure information of the geonet in each calculation zone during the flood season and dry season. Based on the design flow velocity information, wave element information, bank slope ratio information, geonet material information, and pressure information, obtain the maximum normal negative pressure value borne by the geonet in each calculation zone. Step 3: Based on the maximum normal negative pressure value borne by the geonet in each calculation zone, obtain the minimum average reinforcement pressure value required for the geonet in each calculation zone. Step 4: Based on the minimum average reinforcement pressure required per unit area of ​​the geonet in each calculation zone, verify the reinforcement design scheme of the geonet for the revetment project to evaluate the safety and economy of the geonet reinforcement design scheme for the revetment project. In step 1, if the first design water level of the bank protection project is above the flat beach water level, then the first calculation zone is divided into a first sub-calculation zone above the first design water level and a second sub-calculation zone between the first design water level and the flat beach water level according to the first design water level. In step 1, if the second design water level of the bank protection project is located between the flat water level and the design low water level, then the second calculation zone is divided into a third sub-calculation zone between the flat water level and the second design water level, and a fourth sub-calculation zone between the second design water level and the design low water level, according to the second design water level. In step 2, the pressure information includes: the maximum normal negative pressure borne by the geonet in the first calculation zone is the normal negative pressure borne by the geonet in the first calculation zone during the flood season; the maximum normal negative pressure borne by the geonet in the second calculation zone is the larger of the normal negative pressure borne by the geonet in the second calculation zone during the flood season and the normal negative pressure borne by the geonet in the second calculation zone during the dry season; the maximum normal negative pressure borne by the geonet in the third calculation zone is the normal negative pressure borne by the geonet in the third calculation zone during the flood season. In step 3, the minimum average reinforcement pressure required for the geonet in the first calculation zone is equal to the maximum normal negative pressure borne by the geonet in the first calculation zone; the minimum average reinforcement pressure required for the geonet in the second calculation zone is equal to the maximum normal negative pressure borne by the geonet in the second calculation zone; and the minimum average reinforcement pressure required for the geonet in the third calculation zone is equal to the maximum normal negative pressure borne by the geonet in the third calculation zone.

2. The evaluation method for the design of geonet reinforcement for revetment engineering according to claim 1, characterized in that: The normal negative pressure value borne by the geonet in each calculation zone during the flood season is calculated using the following formula: ； Where t is the index of the computation partition; P t PW represents the normal negative pressure borne by the geonet in the t-th calculation zone during the flood season. t PB represents the normal wave negative pressure value borne by the geonet in the t-th calculation zone during the flood season; t PD represents the normal buoyancy pressure exerted on the geonet in the t-th calculation zone during the flood season. t Let be the normal hydrodynamic negative pressure value borne by the geonet in the t-th calculation zone during the flood season; The normal negative pressure borne by the geonet in the second calculation zone during the dry season is calculated using the following formula: ； Wherein, P2′ is the normal negative pressure value borne by the geonet in the second calculation zone during the dry season; PW2′ is the normal wave negative pressure value borne by the geonet in the second calculation zone during the dry season; PB2′ is the normal buoyancy pressure value borne by the geonet in the second calculation zone during the dry season; and PD2′ is the normal dynamic water negative pressure value borne by the geonet in the second calculation zone during the dry season.

3. The evaluation method for the design of geonet reinforcement for revetment engineering according to claim 2, characterized in that: The normal wave negative pressure value borne by the geonet in each calculation zone during the flood season is calculated using the following formula: ； Where α is the first empirical coefficient; γ w H1 is the unit weight of water; L1 is the design wave height of the revetment project during the flood season; L1 is the design wavelength of the revetment project during the flood season; B is the length of a single geonet along the slope inclination direction.

4. The evaluation method for the design of geonet reinforcement for revetment engineering according to claim 2, characterized in that: The normal buoyancy pressure borne by the geonet in each calculation zone during the flood season is calculated using the following formula: ； Where, γ w γ is the specific weight of water; c d is the unit weight of the geonet; d is the thickness of the geonet; m t Calculate the slope ratio of the bank slope in the t-th partition.

5. The evaluation method for the design of geonet reinforcement for revetment engineering according to claim 2, characterized in that: The normal hydrodynamic negative pressure borne by the geonet in each calculation zone during the flood season is calculated using the following formula: ； in, ρ is the reduction factor; w V1 is the density of water; V0 is the design flow velocity of water flowing outside the geogrid of the revetment during the flood season; V1 is the design flow velocity of water flowing inside the geogrid of the revetment during the flood season; m t Calculate the slope ratio of the bank slope in the t-th partition.

6. The evaluation method for the design of geonet reinforcement for revetment engineering according to claim 1, characterized in that: The method for verifying the reinforcement design scheme of the geonet for the revetment project includes the following sub-steps: S401: Obtain the design value of the reinforcement pressure of the geonet in each calculation zone of the reinforcement design scheme of the geonet; S402: Perform a safety assessment of the geonet reinforcement design scheme for the revetment project. If the design reinforcement pressure of the geonet in each calculation zone of the geonet reinforcement design scheme is greater than the minimum average reinforcement pressure required by the geonet in the corresponding calculation zone, then the safety of the geonet reinforcement design scheme for the revetment project is deemed qualified, and proceed to sub-step S403; otherwise, the safety of the geonet reinforcement design scheme for the revetment project is deemed unqualified. S403: Perform an economic evaluation of the geonet reinforcement design scheme for the revetment project. If the difference between the design reinforcement pressure of the geonet in each calculation zone and the minimum average reinforcement pressure required by the geonet in the corresponding calculation zone is less than the preset error value, then the economic evaluation of the geonet reinforcement design scheme for the revetment project is deemed qualified; otherwise, the economic evaluation of the geonet reinforcement design scheme for the revetment project is deemed unqualified.

7. The evaluation method for the design of geonet reinforcement for revetment engineering according to claim 6, characterized in that: The reinforcement design value of the geonet in each calculation zone of the aforementioned geonet reinforcement design scheme is calculated using the following formula: ； Where t is the index of the computation partition; P t ′′ represents the design reinforcement pressure of the geonet in the t-th calculation zone; T t The normal reinforcement force provided by μ to a single reinforcement member on the geonet in the t-th computational partition; t β is the second empirical coefficient. t Let be the average area of ​​the geonet reinforced by each reinforcement member in the t-th calculation partition.

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