Design method of flexible protection system for high-steep environment slope

Abstract

The application discloses a design method of a flexible protection system for a high-steep environment slope, and determines the number of flexible protection nets based on high-steep slope terrain parameters and flexible protection net parameters; determines the arrangement position of each flexible protection net according to the movement track of rolling stones and rockfalls; determines the height of the flexible protection net based on the arrangement position of the flexible protection net; determines the length of each flexible protection net according to the envelope line of the projection range of the bouncing track of the rolling stones and rockfalls; and designs the flexible protection system for the high-steep environment slope based on the number of the flexible protection nets, the arrangement position, the height and the length of each flexible protection net. The application solves the problems of the traditional method, such as the dependence on experience, the existence of a blind area of protection and the waste of resources, by dynamically matching the kinetic energy of the rolling stones and rockfalls with the energy level of the protection net to determine the number, arranging the protection net according to the vertex of the bouncing track, and determining the length of the protection net based on the track projection range, and has the advantages of scientific quantification and precise protection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water conservancy and hydropower engineering safety protection, and particularly relates to a design method of a flexible protection system for a super-high and steep environment slope. BACKGROUND

[0002] Water conservancy and hydropower projects are mostly built in mountain and canyon areas, and the slopes have the characteristics of being high and steep, and the rolling stones and falling stones occur frequently, which threaten the safety of the projects and personnel. The traditional design of the flexible protection system for the super-high and steep environment slope has the following three shortcomings: first, the number of flexible protection nets lacks scientific and quantitative basis, and the existing method mostly relies on experience and does not consider the difference between different engineering grades and the dynamic matching relationship between the kinetic energy of the rolling stones and falling stones and the energy level of the protection nets, which easily leads to insufficient protection or waste of resources; second, the arrangement position and design height of each flexible protection net are relatively rough, and the equal interval and fixed height arrangement are usually adopted without combining the actual bouncing trajectory of the rolling stones and falling stones to carry out fine design, so that there are blind areas of protection and the scientific nature is insufficient; and third, the length of the protection net arranged along the elevation is redundant or insufficient, and the existing method mostly relies on experience to estimate the arrangement length without dynamically analyzing the spatial distribution of the movement path of the rolling stones and falling stones. These problems lead to the fact that the existing protection system is difficult to effectively cope with the complex movement characteristics of the rolling stones and falling stones under the super-high and steep slope environment and cannot achieve precise protection.

[0003] In view of the above problems, the existing technology needs to be improved. SUMMARY

[0004] The purpose of the application is to solve the problems in the background art, provide a design method of a flexible protection system for a super-high and steep environment slope, and has the advantages of scientifically and quantitatively arranging the number of flexible protection nets, determining the position and height of the protection net in combination with the bouncing trajectory of the rolling stones and falling stones, dynamically analyzing the movement path to determine the length of the protection net, thereby eliminating the blind area of protection and achieving precise protection.

[0005] The technical scheme adopted by the application is: a design method of a flexible protection system for a super-high and steep environment slope, comprising the following steps:

[0006] Determine the number of flexible protection nets based on the terrain parameters of the high and steep slope and the parameters of the flexible protection net;

[0007] Determine the arrangement position of each flexible protection net according to the movement trajectory of the rolling stones and falling stones;

[0008] Determine the height of the flexible protection net based on the arrangement position of the flexible protection net;

[0009] Determine the length of each flexible protection net according to the projection range envelope of the bouncing trajectory of the rolling stones and falling stones;

[0010] Design the flexible protection system for the super-high and steep environment slope based on the number of flexible protection nets, the arrangement position, height and length of each flexible protection net.

[0011] Further, the application also proposes that the number of flexible protection nets is determined based on the high and steep slope terrain parameters and the flexible protection net parameters, and the number of flexible protection nets is determined based on the following formula:

[0012] The vertical height from the falling point of the rolling and falling rock to the top of the opening line of the slope of the protected building is determined based on the high and steep slope terrain parameters.

[0013] The mass of the rolling and falling rock is calculated according to the structural plane of the rolling and falling rock.

[0014] The energy level of a single flexible protection net is determined based on the material strength and structure of the flexible protection net.

[0015] The number of flexible protection nets is determined according to the vertical height, the mass of the rolling and falling rock, and the energy level of a single flexible protection net.

[0016] Further, the application also proposes that the number of flexible protection nets is determined by the following formula:

[0017] ;

[0018] Wherein, n is the number of flexible protection nets; INT is the integer function; k1 is the number of safety factors; m is the mass of the rolling and falling rock; g is the acceleration of gravity; h is the vertical height; J r is the energy level of a single flexible protection net.

[0019] Further, the application also proposes that the number of safety factors is determined by looking up the building safety level-number of safety factors table.

[0020] Further, the application also proposes that the arrangement position of each flexible protection net is determined according to the movement trajectory of the rolling and falling rock, and the arrangement position of each flexible protection net is determined according to the following formula:

[0021] The numerical simulation software is used to calculate all possible movement trajectories of the rolling and falling rock, and the vertices of all movement trajectories are extracted to form the maximum bounce height envelope of the rolling and falling rock.

[0022] From the maximum bounce height envelope, the elevations of several lowest bounce points are selected in the order of bounce height from small to large as the arrangement position of each flexible protection net.

[0023] Further, the application also proposes that the height of the flexible protection net is determined by the following formula:

[0024] ;

[0025] Wherein, H 柔i is the height of the i-th flexible protection net; H 弹iH is the height of the arrangement position of the i-th flexible protective net; k2 is a height safety coefficient; R is the maximum diameter of the rolling stone; alpha is the slope angle of the arrangement position of the flexible protective net; and beta is the angle between the flexible protective net and the slope.

[0026] Further, the height safety coefficient is determined by searching a building safety grade-height safety coefficient table.

[0027] Further, the length of each flexible protective net is determined according to the projection range envelope of the bouncing trajectory of the rolling stone, and the length of each flexible protective net is determined according to the projection range envelope of the bouncing trajectory of the rolling stone.

[0028] The numerical simulation software is used to calculate all possible motion trajectories of the rolling stone, the vertical projection range of all motion trajectories on the slope surface is extracted, and the trajectory slope surface coverage area is established.

[0029] According to the elevation of the arrangement position of each flexible protective net, the trajectory lateral distribution length corresponding to the elevation is extracted from the trajectory slope surface coverage area, and the length of the flexible protective net is determined based on the trajectory lateral distribution length.

[0030] Further, the length of the flexible protective net is determined by the following formula:

[0031] ;

[0032] B 柔i is the length of the i-th flexible protective net; B 轨i is the trajectory lateral distribution length corresponding to the elevation of the arrangement position of the i-th flexible protective net; and delta L is a safety length.

[0033] Further, the safety length is determined by searching a building safety grade-safety length table.

[0034] The present application has the following advantages:

[0035] The present application dynamically matches the kinetic energy of the rolling stone and the energy level of the protective net to determine the number of channels, arranges the protective net based on the bouncing trajectory vertex, and determines the length of the protective net based on the trajectory projection range, thereby solving the problems of the traditional method, such as relying on experience, existing blind area of protection and waste of resources, and having the advantages of scientific quantification and precise protection. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The present application has the following advantages: DETAILED DESCRIPTION

[0037] The specific embodiments of the present application will be further described below with reference to the drawings. It should be noted that the description of these embodiments is used to help understand the present application, but does not constitute a limitation on the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0038] In the prior art, water conservancy and hydropower projects are mostly built in high mountain and canyon areas, and the slopes have a significant high and steep feature, and rock rolling and falling frequently threaten the safety of the project. The traditional protection system design has three shortcomings: the number of flexible protection net arrangement depends on experience estimation, and the differences in engineering grades and kinetic energy matching relationship are not considered; the protection net position is arranged at equal intervals without considering the actual bouncing trajectory; the protection length depends on experience estimation, resulting in redundant or insufficient protection range. A hydropower station project once caused equipment damage due to improper arrangement of the protection net, which led to rock rolling and falling breaking through the protection system.

[0039] In order to solve the above problems, the designer found that the traditional method cannot accurately match the kinetic energy of rock rolling and falling and the protection energy level, resulting in protection failure. By analyzing the rock rolling and falling trajectory data, it is found that the bouncing height and position have a nonlinear distribution characteristic. From this, the technical concept is generated: a dynamic correlation model of terrain parameters and protection parameters is established, and the key arrangement parameters are determined through trajectory simulation. The specific solution path is: first, determine the necessary protection number through kinetic energy calculation, then optimize the arrangement position according to the trajectory vertex distribution, calculate the protection height combined with the three-dimensional terrain data, and finally determine the coverage length according to the trajectory projection.

[0040] Therefore, the present application proposes a flexible protection system design method for high and steep environment slope, as shown in Figure 1 The method comprises the following steps: determining the number of flexible protection nets based on high and steep slope terrain parameters and flexible protection net parameters; determining the arrangement position of each flexible protection net according to the motion trajectory of rock rolling and falling; determining the height of the flexible protection net based on the arrangement position; determining the length of each flexible protection net according to the projection range envelope of the rock rolling and falling bouncing trajectory; and designing the flexible protection system for high and steep environment slope based on the determined number, position, height and length of the flexible protection net.

[0041] The high and steep slope terrain parameters refer to the vertical height of the slope, the slope shape and the geological structure data, which can be obtained by laser scanning or geological exploration, and are used to calculate the falling energy of rock rolling and falling. The flexible protection net parameters include the tensile strength of the material, the mesh size and the structure form, which can be obtained by laboratory test, and are used to determine the kinetic energy absorption capacity of a single protection net. The rock rolling and falling motion trajectory is calculated by numerical simulation software, considering the influence of different initial velocities and collision recovery coefficients, to generate a three-dimensional motion path data set. The bouncing trajectory projection range envelope refers to the coverage area formed by the vertical projection of all possible trajectories on the slope surface, which is extracted by a spatial clustering algorithm to obtain the maximum distribution range.

[0042] Specifically, firstly, the total kinetic energy of the rockfall is calculated by the principle of kinetic energy conservation, and the necessary number of protection channels is determined in combination with the energy level of a single protection net. Secondly, the vertex data of the trajectory generated by numerical simulation is extracted, and the distribution point with the lowest bounce height is selected as the layout position of the protection net to ensure coverage of the most dangerous movement path, so that the protection net can cover more than 95% of the bounce points. Then, according to the geometric characteristics of the slope surface at the layout position, a trigonometric function relationship between the height of the protection net and the diameter of the rockfall and the slope angle is established to realize three-dimensional space adaptation, so that the upper edge of the protection net is always higher than the bounce trajectory of the rockfall. Finally, the trajectory projection data is converted into a horizontal distribution length, and the actual length of the protection net is determined after adding a safety margin, so as to accurately capture the maximum distribution range. Each step forms a closed-loop design process, and the blindness of empirical design is eliminated through dynamic parameter matching.

[0043] Through the above technical scheme, the present application realizes dynamic matching of the number of protection channels and the kinetic energy of the rockfall, avoids waste of resources or insufficient protection, accurately covers the bounce danger area at the layout position, eliminates the blind area of the protection arranged at equal intervals, adaptively changes the protection height according to the terrain, ensures effective interception in three-dimensional space, dynamically determines the protection length based on the trajectory projection, realizes full coverage and no redundancy. The application of a certain actual project shows that this method improves the interception efficiency of the protection system to 98%, and reduces the material consumption by about 15%.

[0044] The present application further proposes that the number of flexible protection nets is determined based on the high and steep slope terrain parameters and the flexible protection net parameters, comprising:

[0045] The vertical height from the falling point of the rockfall to the top of the opening line of the slope of the protected building is determined based on the high and steep slope terrain parameters;

[0046] The volume of the rockfall is calculated according to the structural plane of the rockfall, and then the mass is calculated;

[0047] The energy level of a single channel is determined based on the material strength and structure of the flexible protection net;

[0048] The number of flexible protection nets is determined according to the vertical height, the mass of the rockfall, the energy level of a single channel, and the safety factor of the number of channels.

[0049] Wherein, the vertical height refers to the vertical distance between the falling point of the rolling stone and the top of the protected building, which can be measured by a three-dimensional laser scanner or a total station instrument, and is used to quantify the basic condition of the conversion of the potential energy of the rolling stone into kinetic energy. The structural surface calculation volume refers to the structural surface occurrence parameters obtained by geological mapping, which is calculated by a polyhedral volume calculation formula, and the volume can be calculated by reconstructing the geometric shape of the rolling stone using a three-dimensional modeling software, which can eliminate the volume error of the empirical estimation.

[0050] Specifically, the vertical height parameter is obtained by high-precision topographic survey to establish the reference value of the potential energy conversion of the rolling stone. The structural surface occurrence data is used to construct a three-dimensional model of the rolling stone to accurately calculate its volume and mass, avoiding the error accumulation of traditional empirical formula. The energy absorption upper limit model of the single protection system is established by combining the mechanical properties of the protection net material and the parameters of the support structure. The potential energy corresponding to the vertical height, the kinetic energy corresponding to the mass of the rolling stone, and the single energy level are coupled and calculated, and the number of channels is calculated by the energy conservation principle. The safety factor of the number of channels is dynamically adjusted according to the safety level of the building to realize the matching of the protection strength and the engineering level.

[0051] The traditional method relies on engineering experience to estimate the number of protection channels, and does not establish a quantitative relationship between the kinetic energy of the rolling stone and the protection level, which may cause insufficient protection or redundancy. The present scheme accurately calculates the mass of the rolling stone by the structural surface parameters, determines the single energy level by the material strength parameters, and establishes a dynamic balance model of kinetic energy-energy level.

[0052] Through the above technical scheme, the present application solves the problem of lack of scientific quantitative basis in the traditional protection channel number determination method, and realizes the dynamic matching of the kinetic energy of the rolling stone and the protection energy level. By accurately calculating the mass of the rolling stone and the single energy level parameters, the problem of insufficient protection or resource waste caused by empirical estimation is avoided. The safety factor of the number of channels is dynamically adjusted according to the safety level of the building, so that the protection system design meets the differentiated needs of different engineering levels.

[0053] The present application further proposes to determine the number of flexible protection nets by the following formula:

[0054] ;

[0055] Wherein, n is the number of flexible protection nets; INT is the integer function; k1 is the safety factor of the number of channels; m is the mass of the rolling stone; g is the acceleration of gravity; h is the vertical height; J r is the single flexible protection net energy level.

[0056] The rounding function refers to removing the decimal part and retaining the integer part of the calculation result, and can be implemented in a downward rounding or upward rounding manner, and is used to convert the theoretical calculation value into an integer number of channels required in engineering practice, and in the embodiment, the downward rounding manner is adopted, for example, INT (1.9) = 1. The channel safety factor is an adjustment factor reflecting the difference in the protection level of the building, and can be obtained by querying the corresponding relationship table of the building safety level and the channel safety factor, for example, the safety level of the protected building is 1 level, and k1 is 1.2; the safety level of the building is 2 levels, and k1 is 1.15; the safety level of the building is 3 levels, and k1 is 1.1; the safety level of the building is 4 levels, and k1 is 1.05; the safety level of the building is 5 levels, and k1 is 1.0. The mass of the rolling rock and the rockfall is the product of the rockfall volume and the rock density obtained by the structural surface calculation, and the rockfall volume data can be obtained by three-dimensional laser scanning. The energy level of a single flexible protective net is the energy absorption capacity of a single protective net structure under the action of impact load, and can be determined by material tensile test and structural mechanics analysis.

[0057] Specifically, the formula realizes energy dynamic matching calculation by establishing a ratio relationship between the total kinetic energy of the rolling rock and rockfall and the energy level of a single protective net. The total kinetic energy of the rolling rock and rockfall is represented by the product of mass, gravitational acceleration and vertical height, and the vertical height parameter reflects the influence of the steepness of the slope terrain on the acceleration process of the rolling rock and rockfall. After the calculation result is superimposed with the channel safety factor, the final protective channel number can be obtained after rounding function processing. For example, when the calculation value is 2.3 channels, 2 channels can be arranged after rounding. The calculation process replaces the empirical judgment with quantitative parameters to ensure that the protective channel number matches the actual energy level.

[0058] The present application realizes the precise quantitative design of the protective channel number by establishing a dynamic matching model of kinetic energy-energy level, incorporating key parameters such as the mass of the rolling rock and rockfall and the height of the slope into the calculation system, and combining with the safety factor adjustment mechanism. For example, under the same slope height condition, when the mass of the rolling rock and rockfall increases by 30%, the present application can automatically increase the protective channel number. Through the above technical scheme, the present application effectively solves the problem of lack of scientific basis for determining the protective channel number, and realizes the dynamic matching of the kinetic energy of the rolling rock and rockfall and the protective energy level by establishing a parameterized calculation model. The scheme can automatically adjust the protective channel number according to the characteristics such as the size of the rolling rock and rockfall and the height of the slope in specific projects, avoiding the blind area of protection or resource waste phenomenon existing in the traditional empirical method. For example, in projects with large fluctuations in the mass of the rolling rock and rockfall, the formula can automatically generate the corresponding protective channel number configuration scheme to ensure that the protection system always maintains a reasonable matching relationship with the impact energy of the rockfall.

[0059] The present application further proposes that the channel safety factor is determined by looking up the building safety level-channel safety factor table.

[0060] The building safety level-lane safety coefficient table is a parameter mapping table that reflects the corresponding relationship between the engineering safety level and the lane safety coefficient, and can be realized by a hierarchical quantization manner, for example, the building safety level is divided into level 1, level 2 and level 3, and different safety coefficient interval values are set correspondingly. The finding refers to an operation process of obtaining a corresponding value by matching the actual engineering safety level with the preset parameter table, and can be realized by a database query or a table comparison manner.

[0061] Specifically, in the calculation of the flexible protective net lane number, first, the building safety level is determined according to the engineering importance, and then the quantized safety coefficient value matched with the engineering safety level is obtained by querying the pre-established building safety level-lane safety coefficient table. The safety coefficient table is established by combining engineering practice experience and theoretical calculation, and different safety reserve values are set for engineering requirements of different safety levels. By standardizing the mapping of the engineering safety level and the safety coefficient, the safety redundancy of important engineering is ensured, and the over-protection of low-level engineering is avoided.

[0062] The present application realizes the objective and standardized selection of the safety coefficient by establishing a standardized safety level-coefficient corresponding relationship table and taking the engineering safety level as the core decision parameter, which eliminates the random error of human judgment and ensures the accurate matching of the protection level and the engineering importance. The present application effectively solves the problem of lack of scientific basis for the selection of the safety coefficient in the design of the flexible protective net lane number, optimizes the resource allocation under the premise of ensuring the safety of the protection system through the standardized safety level corresponding mechanism, avoids the risk of protection failure of high-level engineering due to insufficient safety reserve, and prevents the waste of materials caused by over-protection of low-level engineering.

[0063] The present application further proposes a method for determining the arrangement position of each flexible protective net according to the motion trajectory of the rolling stone, which comprises: calculating all possible motion trajectories of the rolling stone by using a numerical simulation software, extracting the vertices of all motion trajectories to form a maximum bounce height envelope of the rolling stone, and selecting the elevations of the n lowest bounce points as the arrangement positions of each flexible protective net in order of bounce height from small to large.

[0064] The numerical simulation software refers to a three-dimensional dynamic calculation tool capable of simulating the rolling stone falling stone motion trajectory, and specifically can be realized by using Rockfall Analyst or RocPro 3D software, and the motion trajectory data is generated by inputting the slope terrain parameters and the rolling stone falling stone physical characteristic parameters. The vertex of the motion trajectory refers to a spatial coordinate point at which the vertical distance of the rolling stone falling stone to the slope surface reaches the maximum in a single bouncing process, and specifically can be extracted by a trajectory curvature calculation or a discrete point screening method, and is used for representing the limit height of the rolling stone bouncing. The maximum bouncing height envelope refers to a spatial curve formed by connecting all the vertices of the motion trajectories on the slope profile, and specifically can be generated by using a cubic spline interpolation or a B-spline fitting method, and is used for determining the elevation range of the protective net arrangement.

[0065] Specifically, a set of rolling stone falling stone motion trajectories under different initial conditions is calculated by using the numerical simulation software, covering the rolling stone falling stone events possibly occurring in different regions of the slope. Each trajectory is discretely processed, the three-dimensional coordinate data of each discrete point is extracted, and the vertex position of each bouncing period is identified by using an extreme value screening algorithm. All the vertices are projected onto the slope profile, and a continuous maximum bouncing height envelope is formed by spatial interpolation. Based on the envelope, n lowest bouncing points are selected, and the elevation values thereof directly correspond to the installation reference surface of the flexible protective net, so that the protective net is arranged at the lowest critical position of the actual bouncing height of the rolling stone falling stone.

[0066] When the traditional method arranges the protective net at equal intervals, the protective net can be arranged in an elevation interval that cannot be actually reached by the rolling stone falling stone, resulting in waste of protective resources, or the lowest point of the actual bouncing of the rolling stone falling stone cannot be covered, forming a blind area of protection. The present application dynamically captures the motion trajectory characteristics of the rolling stone falling stone, so that the arrangement position of the protective net is accurately matched with the actual bouncing height distribution, avoiding invalid protection and eliminating the blind area of protection.

[0067] Through the above technical solution, the present application effectively solves the problem of the blind area of protection existing in the traditional equal-interval arrangement method, determines the arrangement elevation of the protective net through the envelope analysis of the bouncing trajectory vertex, so that the interception position of the protective net is matched with the actual motion trajectory height of the rolling stone falling stone, and the reliability and resource utilization efficiency of the protection system are improved.

[0068] The present application further proposes to determine the height of the flexible protective net by the following formula:

[0069] ;

[0070] H 柔i is the height of the i-th flexible protective net, i is 1 to n; H 弹iH is the height of the i-th flexible protective net; k2 is a height safety coefficient; R is the maximum diameter of the rolling stone; a is the slope angle of the flexible protective net; and b is the angle between the flexible protective net and the slope.

[0071] H = k2Rsin (a + b) 弹i H is the elevation value of the i-th protective net, which can be determined by extracting the elevation data of the jumping track vertex of the rolling stone through a numerical simulation software, and is used as a reference for establishing the height of the protective net. k2 is an adjustment coefficient set according to the engineering safety level, which can be obtained from a preset building safety level-coefficient corresponding table through a table lookup method, and is used to match the differentiated needs of the safety margin of different protection levels. R is the maximum outer diameter of the rolling stone, which can be determined through on-site geological investigation or historical disaster data statistics, and is used to quantify the physical boundary of the potential threat of the rolling stone. a is the local slope angle of the protective net installation position, which can be measured through three-dimensional laser scanning or geological mapping technology, and is used to reflect the influence of the terrain on the movement of the rolling stone. b is the angle between the installation surface of the protective net and the slope surface, which can be determined through engineering design requirements or structural stability analysis, and is used to represent the spatial arrangement form of the protective net.

[0072] Specifically, the formula realizes dynamic calculation through multi-dimensional parameter coupling. Taking H 弹i as the reference value, the formula ensures that the protective net covers the vertex area of the jumping track of the rolling stone; the k2 coefficient is introduced to dynamically adjust the protection margin according to different safety levels, so as to avoid insufficient protection or redundancy caused by a single empirical value; the R parameter is combined to include the size of the rolling stone into the calculation system, so as to ensure that the protection height covers the maximum potential threat; and the trigonometric function relationship between a and b is used to convert the terrain gradient and the installation angle into a height correction factor, so as to realize accurate adaptation in three-dimensional space. For example, when the slope angle increases, the value of sin a increases, and the formula automatically increases the height of the protective net to offset the kinetic energy enhancement effect of the rolling stone caused by the steep terrain.

[0073] Compared with the prior art, the traditional method arranges the protective net at a fixed height without considering the dynamic changes of the size of the rolling stone, the jumping track and the terrain parameters, which easily leads to a blind area of protection or waste of materials. The present application realizes adaptive adjustment of the protection height by modeling the physical characteristics of the rolling stone, the elevation of the jumping track vertex, the slope geometric parameters and the safety level into a unified calculation framework. For example, under the same slope conditions, the present application can automatically adjust the height of the protective net according to the diameter difference of the rolling stone.

[0074] By the technical scheme, the application solves the problem of the protection blind area caused by the fixed height design in the traditional method, realizes the accurate matching of the protection height and the rockfall threat characteristics through dynamic calculation, avoids the protection failure caused by insufficient height, and reduces the resource waste caused by excessive design. Meanwhile, by introducing the safety level coefficient, the safety requirements of different engineering scenes can be flexibly adapted, and the scientificity and economy of the protection system are improved.

[0075] The application further proposes that the height safety coefficient is determined by searching the building safety level-height safety coefficient table.

[0076] The building safety level-height safety coefficient table refers to dividing the buildings into different levels according to safety requirements, and configuring corresponding height adjustment coefficients for each level. Specifically, the engineering safety level standard in the industry specification can be used to realize the division, for example, the buildings are divided into level 1, level 2 and level 3, and different safety coefficients are taken for different levels. The height safety coefficient refers to a multiplier factor for adjusting the height of the flexible protection net, which can be realized by the coefficient range defined in the slope protection design specification, for example, the safety level of the protected hydraulic structure is level 1-2, and k2 is 1.1; the safety level of the building is level 3-4, and k2 is 1.05; the safety level of the building is level 5, and k2 is 1.0.

[0077] Specifically, when determining the height of the flexible protection net, first, according to the safety level of the protected building, the corresponding coefficient value is searched from the pre-defined building safety level-height safety coefficient table. Then, the height calculation formula is substituted into the height of the bounce trajectory, the maximum diameter of the rockfall, the slope angle and the installation angle of the protection net, and the result after the coefficient adjustment is used as the final protection net height. For example, when the safety level of the building is level 1, the coefficient 1.1 is used to enlarge the reference height, so that the protection net coverage range extends upwards, avoiding the rockfall from passing over the protection net.

[0078] Compared with the prior art, the traditional method usually uses fixed height or empirical estimate value to arrange the protection net, without considering the protection demand difference of different building safety levels. The application establishes the corresponding relationship between the safety level and the height coefficient, so that the high safety level buildings such as hydropower stations and bridges can automatically match larger protection height margin, and the ordinary buildings can avoid the resource waste caused by excessive protection.

[0079] By the technical scheme, the application achieves the target of dynamically adjusting the protection height according to the importance of the building. For example, in a water conservancy hub project, for a dam, which is a first-class safety building, a coefficient value of 1.1 is obtained by table lookup, so that the height of the protection net is increased by 10%, effectively covering the limit height of the bouncing of the rolling stones; and for a temporary construction road, which is a third-class safety building, a coefficient of 1.05 is used to appropriately increase the height, so as to meet the protection requirement and control the construction cost. The grading adjustment mechanism eliminates the blind area or redundancy problem caused by the traditional fixed height arrangement.

[0080] The application further proposes to determine the length of each flexible protection net according to the envelope line of the projection range of the bouncing trajectory of the rolling stones, including calculating all possible motion trajectories of the rolling stones by using a numerical simulation software, extracting the vertical projection range of all motion trajectories on the slope surface, establishing a trajectory slope surface coverage area; extracting the trajectory lateral distribution length corresponding to the elevation from the trajectory slope surface coverage area according to the elevation of the arrangement position of each flexible protection net, and determining the length of the flexible protection net based on the trajectory lateral distribution length.

[0081] The numerical simulation software refers to a calculation tool for simulating the motion trajectory of the rolling stones, and can be specifically implemented by using a discrete element method or a finite element method software, and the motion trajectory data is generated by inputting the slope terrain parameters and the physical parameters of the rolling stones. The trajectory slope surface coverage area refers to the spatial range formed by the vertical projection of all rolling stone motion trajectories on the slope surface, and can be specifically implemented by forming a polygonal area by superimposing the projection boundaries of all trajectories, and is used to represent the lateral influence range of the rolling stones on the slope. The trajectory lateral distribution length refers to the maximum span of the trajectory projection of the rolling stones on the slope at a specific elevation, and can be specifically calculated by extracting the horizontal coordinate range value of the coverage area at the elevation, and is used to reflect the required protection width at the position.

[0082] Specifically, after generating all possible motion trajectories of the rolling stones by using the numerical simulation software, the vertical projections of the trajectories on the slope surface are superimposed to form a complete trajectory slope surface coverage area. For the elevation position of each flexible protection net arrangement, the horizontal coordinate extreme value corresponding to the elevation is extracted from the coverage area, and the trajectory lateral distribution length is calculated. The length of the protection net is determined according to the distribution length with a safety margin, so that the protection range completely covers the lateral area that the rolling stones at the elevation position can reach. This process directly relates the length of the protection net to the actual motion path of the rolling stones by dynamically analyzing the spatial distribution characteristics of the motion trajectory of the rolling stones, avoiding the protection redundancy or deficiency caused by the traditional experience estimation.

[0083] Compared with the prior art, the traditional method relies on artificial experience to estimate the length of the protective net, does not consider the spatial randomness of the rolling stone rockfall trajectory, and is prone to insufficient protection range or material waste. The present application establishes a trajectory slope coverage area through numerical simulation, determines the length of the protective net based on the lateral distribution of the actual motion path, so that the protection range accurately matches the spatial characteristics of the rolling stone rockfall motion, eliminating the blind area of protection and avoiding resource waste.

[0084] Through the above technical solution, the present application solves the problem of redundant or insufficient length of the protective net caused by the existing method relying on experience estimation, realizes the dynamic matching of the length of the protective net and the actual motion path of the rolling stone rockfall, and effectively improves the reliability and economy of the protection system. By extracting the lateral distribution length of the trajectory to determine the protection range, it is ensured that each protective net completely covers the area that the rolling stone rockfall may reach at the corresponding elevation, avoiding protection loopholes or overdesign caused by experience judgment errors.

[0085] The present application further proposes to determine the length of the flexible protective net by the following formula:

[0086] ;

[0087] Wherein, B 柔i is the length of the i-th flexible protective net, i takes a value of 1~n; B 轨i is the lateral distribution length of the trajectory at the elevation corresponding to the layout position of the i-th flexible protective net; and △L is a safety length related to the safety level of the protected building.

[0088] Wherein, B 轨i refers to the lateral distribution range of the rolling stone rockfall motion trajectory at a specific elevation, which can be specifically analyzed by three-dimensional projection of the rolling stone rockfall motion trajectory using numerical simulation software, and the lateral coverage width of all trajectories at the elevation is extracted to ensure that the protective net covers all potential rolling stone rockfall paths in the area. Wherein, △L refers to an additional length set to cope with the randomness of rolling stone rockfall motion and measurement errors, which can be specifically selected by a safety length table corresponding to the safety level of the building.

[0089] Specifically, first, the vertical projection of the rolling stone rockfall on the slope surface is calculated by numerical simulation software to establish a slope area model covering all possible paths. According to the elevation of the protective net layout position, the lateral distribution length B 轨i of the trajectory at the elevation is extracted to ensure that the lateral coverage range of the protective net completely contains the rolling stone rockfall motion path. On this basis, a safety length △L is added, which is dynamically determined by a safety length table corresponding to the safety level of the building, for example, for a hydropower station dam with a safety level of one, △L is selected as 50 meters, so that the length of the protective net increases on the basis of covering the measured trajectory width, eliminating the blind area of protection caused by the randomness of trajectory distribution, and avoiding material waste caused by excessive lengthening.

[0090] Compared with the prior art, the existing method relies on artificial experience to estimate the length of the protective net, does not consider the spatial distribution characteristics of the rolling stone and rockfall trajectory, and is prone to local protection deficiency or overall redundancy. The present application accurately quantifies the lateral distribution range of the trajectory through numerical simulation, and dynamically adjusts the additional length according to the safety level, so that the length of the protective net meets the coverage and economic requirements at the same time.

[0091] Through the above technical scheme, the present application solves the problem of unreasonable length design of the protective net along the elevation in the traditional method, accurately calculates the lateral coverage range of the trajectory through dynamic analysis of the spatial distribution characteristics of the rolling stone and rockfall movement path, and adds a scientifically quantified safety length based on the safety level of the building, so that the length of the protective net can completely intercept the rolling stone and rockfall, and avoid resource waste caused by redundant arrangement, significantly improving the reliability and economy of the super-high and steep slope protection system.

[0092] The present application further proposes that the safety length is determined by looking up the building safety level-safety length table.

[0093] The safety length refers to the protective extension of the flexible protective net based on the lateral distribution length of the trajectory, which can be realized through the corresponding relationship table established in advance in the engineering specification. The table divides the building safety level into 1 to 5 levels, and each level corresponds to different additional length values. The building safety level-safety length table refers to the database recording the corresponding relationship between buildings of different importance and protective extension, which can store the mapping relationship between safety level and additional length in the form of a two-dimensional matrix. By inputting the safety level of the building, the corresponding safety length parameter can be output. For example, the safety level of the protected building is 1-2, and the value of △L is 50m; the safety level of the building is 3-4, and the value of △L is 25m; the safety level of the building is 5, and the value of △L is 10m.

[0094] Specifically, when determining the length of the flexible protective net, first, the safety level classification of the building to which the project belongs is obtained, then the safety level-safety length corresponding table prepared in advance is queried, and the additional protection range value corresponding to the level is extracted. The lateral distribution length of the trajectory is superimposed with the safety length obtained by looking up the table to form the final protective net arrangement length. This dynamic adjustment mechanism based on safety level automatically expands the length of the protective net corresponding to important buildings, and smaller additional length is used for ordinary buildings, achieving accurate matching of the protection range and safety requirements of the project.

[0095] Through the technical scheme, the problem that the arrangement length of the protective net along the elevation does not match the actual demand is effectively solved. By quantifying the corresponding relationship between the safety length and the building grade, the risk of the rolling stone and the rockfall falling over the net due to the insufficient additional length is avoided, and the material waste caused by the excessive expansion is prevented, so that the balance between the protection effect and the economy is achieved.

[0096] It should be understood that the particular order or hierarchy of steps in the processes disclosed is an example. Based upon design preferences, it should be understood that the particular order or hierarchy of steps in the processes can be rearranged while remaining within the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

[0097] In order to make the description of the present disclosure more detailed and complete, the above describes the illustrative description for the embodiments and specific examples of the present application; but this is not the only form of implementing or using the specific examples of the present application. The embodiments include the features of the specific examples and the method steps and their order for constructing and operating the specific examples. However, other specific examples can also be used to achieve the same or equivalent functions and step orders.

[0098] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. The contents not described in detail in the specification belong to the prior art known to those skilled in the art.

Claims

1. A design method of flexible protection system for high and steep slope environment, characterized in that: the number of flexible protection nets is determined based on the parameters of high and steep slope terrain and the parameters of flexible protection net; the arrangement position of each flexible protection net is determined according to the movement trajectory of rolling and falling rock; the height of flexible protection net is determined based on the arrangement position of flexible protection net; the length of each flexible protection net is determined according to the envelope line of projection range of bouncing trajectory of rolling and falling rock; the flexible protection system for high and steep slope environment is designed based on the number of flexible protection nets, the arrangement position, the height and the length of each flexible protection net; the number of flexible protection nets is determined based on the parameters of high and steep slope terrain and the parameters of flexible protection net, including: the vertical height from the falling point of rolling and falling rock to the top of opening line of slope of protected building is determined based on the parameters of high and steep slope terrain; the mass of rolling and falling rock is calculated according to the structural plane of rolling and falling rock; the energy level of single flexible protection net is determined based on the material strength and structure of flexible protection net; the number of flexible protection nets is determined according to the vertical height, the mass of rolling and falling rock and the energy level of single flexible protection net; the arrangement position of each flexible protection net is determined according to the movement trajectory of rolling and falling rock, including: all possible movement trajectories of rolling and falling rock are calculated by using numerical simulation software, and the vertexes of all movement trajectories are extracted to form the envelope line of maximum bouncing height of rolling and falling rock; the elevations of several lowest bouncing points are selected as the arrangement positions of each flexible protection net in the order of bouncing height from small to large; the height of flexible protection net is determined by the following formula: the length of each flexible protection net is determined according to the envelope line of projection range of bouncing trajectory of rolling and falling rock, including: all possible movement trajectories of rolling and falling rock are calculated by using numerical simulation software, and the vertical projection range of all movement trajectories on slope surface is extracted to establish the trajectory slope surface coverage area; the trajectory lateral distribution length corresponding to the elevation of arrangement position of each flexible protection net is extracted from the trajectory slope surface coverage area, and the length of flexible protection net is determined based on the trajectory lateral distribution length; the number of flexible protection nets is determined by the following formula: the number safety factor is determined by looking up the building safety level-number safety factor table; the height safety factor is determined by looking up the building safety level-height safety factor table; the length of flexible protection net is determined by the following formula: the safety length is determined by looking up the building safety level-safety length table. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ； H 柔i is the height of the i-th flexible protective screen; H 弹i is the height at which the i-th flexible protective screen is arranged; k2 is a height safety factor; R is the maximum diameter of the rolling or falling rock; α is the slope angle of the arrangement position of the flexible protective screen; and β is the angle between the flexible protective screen and the slope. ​ ​ ​ 2. The design method of flexible protection system for high-steep slope in high-steep environment according to claim 1, characterized in that, ​ ； Wherein, n is the number of flexible protective net; INT is the integer function; k1 is the number of safety factor; m is the mass of rockfall; g is the acceleration of gravity; h is the vertical height; J r is the energy level of single flexible protective net.

3. The design method of flexible protection system for high-steep slope in high-steep environment according to claim 2, characterized in that: ​ 4. The design method of flexible protection system for high-steep slope in high-steep environment according to claim 1, characterized in that: ​ 5. The design method of flexible protection system for high steep slope in high steep environment according to claim 1, characterized in that, ​ ； Wherein, B 柔i is the length of the i-th flexible protective screen; B 轨i is the track transverse distribution length of the elevation corresponding to the arrangement position of the i-th flexible protective screen; and ΔL is the safety length.

6. The design method of flexible protection system for high-steep slope in high-steep environment according to claim 5, characterized in that: ​

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