Damage monitoring method for stone wall structure

Abstract

The present invention relates to the field of protection against rockfall disasters, and discloses a multi-level energy dissipation buffer system, a design method, and a rock retaining wall structure damage monitoring method, which are used to improve the impact resistance of protection projects and monitor the health status of rock retaining wall structures during project operation. In the early stage of the construction of the rockfall protection project, the present invention first lays vegetation on the unstable slope surface; secondly, by setting up a rock retaining wall structure; during the operation of the rockfall protection project, firstly, numerical simulation methods are used to carry out simulation calculations for different working conditions of potential rockfall disasters impacting the rock retaining wall structure, and by defining damage factors, the vulnerable position and degree of vulnerability of the rock retaining wall structure under the impact load of rockfall are identified; then, according to the vulnerable position and degree of vulnerability data of the rock retaining wall calculated by the numerical simulation software, rapid local detection can be carried out on site to more accurately determine the degree of damage to the rock retaining wall structure. The present invention is suitable for rockfall protection and health detection of protection projects.

Description

Technical Field

[0001] The invention relates to the field of protection against rockfall disasters, and in particular to a method for monitoring damage of a rock-blocking wall structure. Background Art

[0002] Rolling stone disaster refers to the dynamic evolution process in which individual rocks move rapidly downward along the slope after the surface of the geological body becomes unstable, and pose a direct threat to human activities or engineering structures within the range of their movement. Rolling stone disasters have now become the third largest secondary mountain disaster after landslides and debris flows. They are characterized by sudden occurrence, strong randomness, and unpredictability, and are accompanied by complex energy transformation. Rolling stone disasters usually develop in the high mountain canyon areas of the Hengduan Mountains and the eastern edge of the Qinghai-Tibet Plateau, involving many provinces (cities, regions) such as Sichuan, Tibet, and Hubei, and are widely distributed. According to statistics from the National Bureau of Statistics, from 2018 to 2019, a total of 2,096 collapse and rolling stone disasters occurred in my country, accounting for 22.91%, seriously affecting the lives and property safety of the people.

[0003] At present, the protection measures against rockfall disasters are divided into active protection and passive protection. Among them, stone retaining walls and sheds are widely used in mountainous anti-rockfall projects as the main passive protection measures. However, most traditional stone retaining wall structures are made of concrete, which have pain points such as high rigidity, poor site suitability, and limited impact resistance. Further research is needed to make the stone retaining wall structure achieve the effect of "combining rigidity and flexibility" to improve the impact resistance of the structure.

[0004] In addition, when a rockfall disaster occurs, the huge impact force generated by the rockfall hitting the structure often causes considerable damage to the stonewall structure, affecting the normal operation of the structure. In order to quickly maintain the damaged structure and restore the structure's resistance to rockfall impact, engineering and technical personnel often use displacement, acceleration and other sensor instruments on the stonewall for effective monitoring. Once the structure is damaged, the data collected by the monitoring instrument will be used for early warning, and repair work can be carried out on site in time. However, the current research on damage monitoring of rockwall structures impacted by rockfall is still in the preliminary research stage. Most of the structural damage judgments are based on the displacement, acceleration and other characteristic parameters of the structure surface for comprehensive judgment. Further research is needed to truly reflect the changes in the structure before and after the rockfall impact, including the need for further accurate identification of the damage location and the need for quantitative evaluation of the degree of damage.

[0005] Therefore, how to design a stone wall protection system that is both rigid and flexible, has significant energy consumption effects, and incorporates ecological and environmental protection concepts in accordance with local conditions, and how to propose a more accurate stone wall structure damage monitoring method are technical problems that need to be urgently solved by engineering and technical personnel in this field. Summary of the invention

[0006] The technical problem to be solved by the present invention is: to propose a multi-level energy dissipation buffer system, a design method and a stone-blocking wall structure damage monitoring method, to improve the impact resistance of the protection project through the multi-level protection of the multi-level energy dissipation buffer system against rolling stone disasters, and to provide technical support for the health monitoring of the stone-blocking wall structure during the operation of the project through the stone-blocking wall structure damage monitoring method.

[0007] To solve the above problems, the technical solution adopted by the present invention is:

[0008] First, the present invention provides a multi-stage energy dissipation buffer system, including vegetation and a stone wall structure, wherein the vegetation is laid on the slope surface of an unstable slope, and the stone wall structure is arranged at the bottom of the unstable slope; the stone wall structure includes a concrete wall and a composite cushion layer, and the composite cushion layer includes a first soft buffer layer, a hard buffer layer and a second soft buffer layer from front to back. Among them, the soft buffer layer and the hard buffer layer in the present invention are relative, and in implementation, as long as the stiffness of the hard buffer layer is greater than the stiffness of the first soft buffer layer and the second soft buffer layer. The addition of a hard buffer layer can help reduce the effective depth of the rolling stone penetrating into the first soft buffer layer and the second soft buffer layer, and provide stiffness to protect the stone wall structure from direct penetration of the rolling stone.

[0009] Furthermore, the first soft buffer layer can be a sand layer, the second soft buffer layer can be a foam plastic layer, and the hard buffer layer can be a steel plate layer. Sand is easy to obtain and has good deformation characteristics, and foam plastic is lightweight, highly resilient, and has good buffering performance, which can greatly reduce and disperse the impact force generated by rolling stones impacting the stone wall structure, while saving construction costs. The steel plate has the advantages of high strength and good toughness, and provides rigidity guarantee for protecting the stone wall structure from direct penetration of rolling stones.

[0010] Secondly, the present invention further provides a corresponding multi-stage energy dissipation buffer system design method for the above multi-stage energy dissipation buffer system, comprising the following steps:

[0011] Planting vegetation on unstable slopes;

[0012] A rock-blocking wall structure is set at the bottom of the unstable slope; wherein the rock-blocking wall structure includes a concrete wall and a composite cushion layer, the composite cushion layer is located at the front end of the concrete wall, and the composite cushion layer includes a first soft buffer layer, a hard buffer layer and a second soft buffer layer from front to back. wherein the first soft buffer layer is a sand layer, the second soft buffer layer is a foam plastic layer, and the hard buffer layer is a steel plate layer.

[0013] Furthermore, the specific steps of laying vegetation include:

[0014] Based on the survey data from previous drone aerial surveys and manual field investigations, we first carried out an evaluation of the stability and hazard of dangerous rock masses, and classified the dangerous rock masses on unstable slopes according to their stability and hazard, so as to obtain information on the types and distribution patterns of dangerous rock masses on unstable slopes. Subsequently, based on the classified distribution range of dangerous rock masses, we laid vegetation that suited the local soil conditions on the slope surface of the unstable slope, and arranged the density of vegetation in a targeted manner according to the classified hazard level of the dangerous rock masses.

[0015] Furthermore, before setting the stone wall structure, the following steps are also included:

[0016] Based on the existing geological information and survey data, and using the rockfall trajectory simulation software as the foundation, simulation work was carried out on the possible collapse and rockfall disasters caused by unstable slopes to obtain the falling position and flight trajectory of the rocks; and the impact force of the rocks was calculated according to engineering specifications to provide a design basis for the arrangement of the height, thickness and width of the stone retaining wall structure.

[0017] Finally, the present invention also provides a method for monitoring damage of a stone wall structure, which is applied to the stone wall structure in the above-mentioned multi-stage energy dissipation buffer system, and the damage monitoring method comprises the following steps:

[0018] S1. During the operation of the rockfall protection project, based on the on-site investigation data, numerical simulation methods were first used to carry out simulation calculations for different working conditions of potential rockfall disasters impacting the rockfall wall structure, and by defining damage factors, the vulnerable locations and degrees of the rockfall wall structure under the impact load of rockfall were roughly identified;

[0019] S2. Based on the vulnerable locations and damage degree data of the stone retaining wall structure calculated by numerical simulation software, ultrasonic non-destructive testing methods are used on site to conduct rapid local testing regularly to more accurately identify the damage degree of the stone retaining wall structure.

[0020] Furthermore, step S1 specifically includes:

[0021] Firstly, according to the size and location of the dangerous rock mass obtained in the previous investigation, and combined with the size and location information of the multi-level rock-blocking wall structure, the numerical model of the rolling stone impact multi-level rock-blocking wall system under different working conditions was established using finite element numerical simulation software;

[0022] Then the constitutive model and parameters are selected for the materials involved in the numerical model;

[0023] The damage factor is defined from the perspective of energy loss, and the strain energy density of the damaged concrete material is calculated based on the defined damage factor. Furthermore, based on the uniaxial tension and compression constitutive relationship of concrete, the variation law of the damage variable and the tensile or compressive strain of concrete is calculated.

[0024] Based on the definition of the material constitutive model, the numerical calculation of the stone rolling impact on the stone retaining wall structure under different working conditions is carried out by dividing the grid, setting the boundary conditions and load conditions. After the calculation is completed, the tensile or compressive damage range of the stone retaining wall structure under different working conditions is obtained through the post-processing function of the numerical simulation software.

[0025] Furthermore, the damage factor is defined according to the following formula:

[0026]

[0027] Where D is the damage factor of concrete material; W0 is the strain energy density of undamaged concrete material; W ε is the strain energy density of damaged concrete material.

[0028] Furthermore, step S2 specifically includes:

[0029] The tensile or compressive damage range of the rock-blocking wall structure under different rock-rolling impact conditions is calculated by numerical simulation software, and a corresponding data cloud platform is further constructed to store and call the vulnerable data of the rock-blocking wall structure;

[0030] At the completion of the rockfall protection project, an ultrasonic detector was used to detect the vulnerable parts of the rockfall wall structure in turn to obtain the initial ultrasonic wave velocity C at the vulnerable parts. 0n and the initial ultrasonic amplitude T 0n ;

[0031] During the operation of the rockfall protection project, once a rockfall disaster occurs, it is discovered in time through satellite remote sensing and the deployment of wireless sensors on unstable slopes. Then, based on the data information on the vulnerable position and degree of vulnerability of the rockfall wall in the data cloud platform, an ultrasonic detector is used to detect the vulnerable position of the rockfall wall after the rockfall disaster occurs, and the ultrasonic wave velocity C of the damage at the vulnerable position is obtained. 1n and the damaging ultrasonic amplitude T 1n ;

[0032] The ultrasonic wave velocity is defined as the damage variable to characterize the damage characteristics of the concrete inside the stone wall under the impact load of rolling stones:

[0033]

[0034] Where: D cn is the damage degree at different positions on the stone wall; C 1n is the velocity of the damage ultrasonic wave at different positions on the stone wall; C 0n is the initial post-ultrasonic wave velocity at different positions on the stone wall;

[0035] The change of ultrasonic amplitude is used as the characteristic parameter of concrete damage, and the ultrasonic wave velocity parameter is used as an auxiliary parameter to jointly evaluate the damage degree of the main structure of the stone retaining wall under the impact load of rolling stones.

[0036] The beneficial effects of the present invention are:

[0037] 1. The multi-stage energy dissipation buffer system and its design method proposed by the present invention have the following beneficial effects:

[0038] (1) By laying vegetation on unstable slopes, not only can the energy dissipation be achieved step by step during the movement of the rolling stones, but it can also stabilize the slope and protect the slope, and improve the ecological appearance;

[0039] (2) By setting up a sand-steel plate-foam plastic composite cushion in front of the stone retaining wall, it can provide a good buffering effect for the structure and provide a strong guarantee for the structure to be protected from serious damage caused by the impact of rolling stones.

[0040] 2. The beneficial effects of the stone wall structure damage monitoring method proposed by the present invention include:

[0041] (1) In the early stage of the operation of the rock-blocking wall structure protection project, the stress state of the structure under different rock-rolling impact conditions was simulated by using finite element numerical simulation software to obtain the vulnerable range of the main structure of the rock-blocking wall, providing data support for the subsequent accurate detection of the damage of the rock-blocking wall structure after rock-rolling impact, greatly saving the time and cost of detecting the damage of the rock-blocking wall structure;

[0042] (2) By conducting ultrasonic nondestructive testing at different vulnerable locations of the stone wall before and after the impact of the rolling stones, the degree of damage to the stone wall structure can be accurately and quantitatively evaluated, making it easier for maintenance personnel to carry out timely repairs. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A flow chart of a multi-stage energy dissipation buffer system and a damage monitoring method provided by an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of the structure of a multi-stage energy dissipation buffer system provided in an embodiment of the present invention;

[0045] Figure 3 An implementation diagram of a stone wall structure damage monitoring method provided by an embodiment of the present invention;

[0046] Figure 4 A model diagram of a rock-rolling impact stone-blocking wall structure provided in an embodiment of the present invention;

[0047] Figure 5 A compressive damage diagram of the main structure of the stone-blocking wall provided by an embodiment of the present invention under the impact load of rolling stones;

[0048] Figure 6 A tensile damage diagram of the main structure of the stone retaining wall provided in an embodiment of the present invention under the impact load of rolling stones.

[0049] The numbers in the figure are: 1 is rolling stone, 2 is vegetation, 3 is sand layer, 4 is steel plate layer, 5 is foam plastic layer, and 6 is concrete wall. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings and figures in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] The embodiment of the present invention provides a multi-stage energy dissipation buffer system design method and a damage monitoring method based on a stone wall structure, such as Figure 1 As shown, the following steps are included:

[0052] S101. In the early stage of the construction of the rockfall protection project, vegetation adapted to local soil conditions shall be laid on the potentially unstable slopes around the protection project.

[0053] In specific implementation, step S101 may specifically include: first, based on the survey data of previous drone aerial surveys and manual field investigations, an evaluation of the stability and hazard of dangerous rock masses is carried out, and the stability and hazard of dangerous rock masses on unstable slopes are divided, so as to obtain information such as the types and distribution patterns of dangerous rock masses on unstable slopes formed during the construction of transportation projects such as roads and railways; then, based on the divided distribution range of dangerous rock masses, vegetation adapted to local soil conditions is laid on the slope surface of the unstable slope, and the density of vegetation is arranged in a targeted manner according to the divided hazard level of the dangerous rock masses, which can not only reduce the impact energy during the movement of landslides and rolling stones, but also achieve the effect of consolidating soil and protecting slopes.

[0054] Specifically, in the early stage of the construction of the rockfall protection project, the basic geological information of the unstable slope can be obtained by using drone aerial surveys and manual field surveys. On this basis, the stability and hazard evaluation of the dangerous rock mass on the slope is carried out in a qualitative or quantitative manner according to the existence form of the dangerous rock mass, and the characteristics and hazard analysis images of the dangerous rock mass are established based on the evaluation results.

[0055] Subsequently, vegetation of different densities and suitable for local growth is laid on the slope surface according to the distribution range and degree of hazard of dangerous rock masses. For example, if there are dangerous rock masses with a greater degree of hazard in a certain area of ​​the unstable slope, relatively dense vegetation can be laid within the distribution range of the dangerous rock masses to minimize the kinetic energy accumulated by the dangerous rock masses during movement. If there are dangerous rock masses in a certain area of ​​the unstable slope and the degree of hazard is relatively small, vegetation can be laid relatively loosely within its influence range, which can achieve both a beautiful greening effect and a buffering effect.

[0056] S102. A rock retaining wall structure is set at the bottom of the unstable slope, wherein the rock retaining wall structure includes a concrete wall and a composite cushion layer composed of sand-steel plate-foam plastic, and the composite cushion layer is located at the front end of the concrete wall.

[0057] In the specific implementation, step S102 may specifically include: (1) setting up a rock retaining wall structure, based on the existing geological data and survey data, and using the Rocfall rock rolling trajectory simulation software, to simulate the collapse and rock rolling disasters that may be caused by unstable slopes, and obtain data such as the falling position and flight trajectory of the rock rolling; and calculate the impact force of the rock rolling according to relevant specifications, so as to provide a design basis for the arrangement of the height, thickness and width of the rock retaining wall; (2) laying a composite cushion layer composed of sand, steel plate and foam plastic. On the basis of laying out the main structure of the rock retaining wall, a composite cushion layer composed of sand, steel plate and foam plastic of a certain thickness is laid in front of the rock retaining wall. By combining the convenient material acquisition and good deformation characteristics of sand and the light weight, high resilience and good cushioning performance of foam plastic, the impact force generated by the rock rolling impacting the rock retaining wall structure can be greatly reduced, while saving construction costs; the addition of steel plates can help reduce the effective depth of the rock rolling penetrating into the sand and foam plastic, and provide rigidity guarantee for protecting the rock retaining wall structure from direct penetration of the rock rolling.

[0058] S103. During the operation of the rockfall protection project, based on the on-site investigation data, numerical simulation methods are first used to carry out simulation calculations for different working conditions of potential rockfall disasters impacting the rockfall wall structure. By defining damage factors, the vulnerable locations and degree of vulnerability of the rockfall wall structure under the impact load of rockfall can be roughly identified.

[0059] In the specific implementation, step S103 may specifically include: firstly, according to the size and position of the dangerous rock mass actually investigated in the early stage, and in combination with the size and position information of the multi-level rock retaining wall structure, a numerical model of the rolling stone impact multi-level rock retaining wall system under different working conditions is established using finite element numerical simulation software;

[0060] Then, the constitutive model and parameters of the materials involved in the numerical model, such as rolling stones, sand, and foam plastics, were selected. The main structure of the stone wall is mostly made of concrete. In order to accurately describe the dynamic behavior and damage characteristics of the concrete structure under the impact load of rolling stones, the concrete plastic damage model was selected for description. Among them, the damage factor is defined from the perspective of energy loss:

[0061]

[0062] Where D is the damage factor of concrete material; W0 is the strain energy density of undamaged concrete material; W ε is the strain energy density of the damaged concrete material. Based on the definition of the damage factor, the Simpson integral method is used to calculate the strain energy density of the damaged concrete material, and further based on the uniaxial tension and compression constitutive relationship of concrete, the variation law of the damage variable D and the tensile or compressive strain of concrete is calculated.

[0063] Among them, according to GB50010-2010 "Concrete Structure Design Code", the tension and compression constitutive equations of concrete are:

[0064] When x≤1,

[0065] y=α a x+(3-2α a )x 2 +(α a -2)x 3 (2)

[0066] When x>1,

[0067]

[0068] Where:

[0069] αa—is the parameter value of the rising section of the uniaxial compressive stress-strain curve;

[0070] α d —Parameter value of the descending section of the uniaxial compressive stress-strain curve;

[0071] f c — is the uniaxial compressive strength of concrete;

[0072] ε c —For f c The corresponding peak compressive strain of concrete.

[0073] When x≤1,

[0074] y=1.2x-0.2x 6 (6)

[0075] When x>1,

[0076]

[0077] Where:

[0078] α t — is the parameter value of the descending section of the uniaxial tensile stress-strain curve;

[0079] f t — is the uniaxial tensile strength of concrete;

[0080] ε t —For f t The corresponding peak tensile strain of concrete.

[0081] Based on the definition of the material constitutive model, the numerical calculation of the rockfall impact on the rock retaining wall structure under different working conditions is carried out by dividing the grid, setting boundary conditions and load conditions. After the calculation is completed, the tensile or compressive damage range of the rock retaining wall structure under different working conditions can be obtained through the post-processing function of the numerical simulation software.

[0082] S104. Subsequently, based on the vulnerable position and vulnerability data of the stone retaining wall calculated by the numerical simulation software, ultrasonic non-destructive testing methods can be used on-site to conduct rapid local testing and more accurately determine the degree of damage to the stone retaining wall structure.

[0083] In specific implementation, step S104 may specifically include calculating the tensile or compressive damage range of the rock retaining wall structure under different rock rolling impact conditions through numerical simulation software, and further constructing a corresponding data cloud platform to store and call the vulnerable data of the rock retaining wall structure.

[0084] When the rolling stone protection project is completed, an ultrasonic detector can be used to detect the vulnerable parts of the stone wall structure in turn to obtain the initial ultrasonic wave velocity C at the vulnerable parts. 0n and the initial ultrasonic amplitude T 0n .

[0085] During the operation of the rockfall protection project, once a rockfall disaster occurs, it can be discovered in time through satellite remote sensing and the deployment of wireless sensors on unstable slopes. Then, based on the data information on the vulnerable position and degree of vulnerability of the rockfall wall in the data cloud platform, an ultrasonic detector can be used to detect the vulnerable position of the rockfall wall after the rockfall disaster occurs, and the ultrasonic wave velocity C of the damage at the vulnerable position can be obtained. 1n and the damaging ultrasonic amplitude T 1n .

[0086] The ultrasonic wave velocity is defined as the damage variable to characterize the damage characteristics of the concrete inside the stone wall under the impact load of rolling stones:

[0087]

[0088] Where:

[0089] D cn — is the degree of damage at different locations on the stone wall;

[0090] C 1n — is the damage ultrasonic wave velocity at different positions on the stone wall;

[0091] C 0n — is the initial post-ultrasonic wave velocity at different positions on the stone wall.

[0092] The change of ultrasonic amplitude can be used as a characteristic parameter of concrete damage, and the ultrasonic wave velocity parameter can be used to jointly evaluate the damage degree of the main structure of the stone wall under the impact load of rolling stones. The damage degree D of the stone wall structure at different positions under the impact load of rolling stones obtained based on the evaluation cn .

[0093] It should be noted that since the above-mentioned multi-stage energy dissipation buffer system case description provided in the embodiment of the present invention needs to be designed and explained according to the specific slope conditions, the specific embodiment is not mentioned in the embodiment of the present invention. Figure 2 Shown is a schematic structural diagram of a multi-stage energy dissipation buffer system.

[0094] The following is an example of a rolling stone impacting a multi-level stone wall structure to describe in detail the damage monitoring method based on the stone wall structure provided by the embodiment of the present invention. Figure 3 The implementation idea diagram of this method is as follows:

[0095] like Figure 4 As shown in the figure, it is assumed that a spherical rolling stone with a radius of 0.8m hits a multi-level stone retaining wall structure at a speed of 40.0m / s. The stone retaining wall structure consists of four parts: (1) Sand cushion layer: the upper width of the sand cushion layer is 0.2m, the lower width is 0.8m, the height is 3.0m, and the longitudinal length is 10.0m; (2) Steel plate layer: the steel plate thickness is 4.0mm, the height is 3.0m, and the longitudinal length is 10.0m; (3) EPE foam plastic layer: the EPE foam plastic thickness is 0.1m, the height is 3.0m, and the longitudinal length is 10.0m; (4) Stone retaining wall main structure (i.e. concrete wall): the upper width of the stone retaining wall main structure is 1.0m, the lower width is 2.0m, the height is 3.0m, and the longitudinal length is 10.0m.

[0096] On the basis of establishing the above-mentioned rolling stone impact multi-level stone retaining wall structure, material parameter assignment is performed. Among them, the rolling stone is considered to be a rigid body with a density of 2500kg / m 3 The sand cushion layer adopts the Drucker-Prager model, and the density is considered to be 2000kg / m3 , the internal friction angle is 48°, the elastic modulus is 0.039 GPa, and the Poisson's ratio is 0.3; the steel plate adopts an elastic-plastic model and the density is considered to be 7850 kg / m 3 , elastic modulus is 200GPa, Poisson's ratio is 0.3; EPE foam plastic adopts Low Density Foam model, density is 25kg / m 3 , elastic modulus is 0.27MPa, Poisson's ratio is 0.13; the main structure of the stone wall adopts the concrete plastic damage model, considering the density of 2390kg / m 3 , the elastic modulus is 31.5 GPa, and the Poisson's ratio is 0.2.

[0097] Through material assignment, meshing, contact setting and load boundary condition setting are further performed, and finally numerical simulation calculations are carried out.

[0098] like Figure 5 and Figure 6 , is the damage calculation result of the multi-stage rock retaining wall structure under a single working condition. From the figure, we can clearly identify the tensile and compressive damage positions and damage degrees of the main structure of the rock retaining wall under this rock rolling impact condition. The main manifestation is that there are more obvious damages at the center of the rock rolling impact and near the bottom of the rock retaining wall. Therefore, the ultrasonic detection instrument can be focused on the above-mentioned positions for targeted detection.

[0099] Furthermore, during the completion of the stone wall structure, an ultrasonic testing instrument is placed at the above-mentioned vulnerable parts to perform measurements in the initial state, and the initial ultrasonic wave velocity C is obtained. 0n and the initial ultrasonic amplitude T 0n .

[0100] Furthermore, during the operation of the rockfall protection project, once a rockfall disaster occurs, it can be discovered in time through satellite remote sensing means and wireless sensors arranged on unstable slopes. Then, ultrasonic detectors are used to detect damage at the same vulnerable parts, and the damage ultrasonic wave velocity C at the vulnerable parts is obtained. 1n and the damaging ultrasonic amplitude T 1n .

[0101] Furthermore, the above-mentioned damage discriminant formula based on ultrasonic wave velocity changes is used to carry out quantitative evaluation of stone-blocking wall structure damage. The change in ultrasonic amplitude can assist ultrasonic wave velocity parameters in jointly evaluating the degree of damage to the main structure of the stone-blocking wall under the impact load of rolling stones.

[0102] The multi-stage energy dissipation buffer system, design method and stone wall structure damage monitoring method provided by the present invention are introduced in detail above. In this article, specific examples are used to illustrate the principle and implementation method of the damage monitoring method in the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for monitoring damage of a rock-block wall structure, the method for monitoring damage of the rock-block wall structure being applied to a rock-block wall structure, the rock-block wall structure comprising a concrete wall and a composite cushion layer, the composite cushion layer being located at the front end of the concrete wall; the composite cushion layer comprising a first soft buffer layer, a hard buffer layer and a second soft buffer layer in sequence from front to back, characterized in that: The damage monitoring method comprises the following steps: S1. During the operation of the rockfall protection project, based on the on-site investigation data, numerical simulation methods are first used to carry out simulation calculations for different working conditions of potential rockfall disasters impacting the rockfall wall structure, and by defining damage factors, the vulnerable position and degree of the rockfall wall structure under the impact load of rockfall are roughly identified; specifically, the following steps are included: Firstly, according to the size and location of the dangerous rock mass obtained in the previous investigation, and combined with the size and location information of the multi-level rock-blocking wall structure, the numerical model of the rolling stone impact multi-level rock-blocking wall system under different working conditions was established using finite element numerical simulation software; Then the constitutive model and parameters are selected for the materials involved in the numerical model; The damage factor is defined from the perspective of energy loss, and the strain energy density of the damaged concrete material is calculated based on the defined damage factor. Furthermore, based on the uniaxial tension and compression constitutive relationship of concrete, the variation law of the damage variable and the tensile or compressive strain of concrete is calculated. On the basis of defining the material constitutive model, numerical calculations of the rockfall impacting the rock retaining wall structure under different working conditions are carried out by dividing the grid, setting boundary conditions and load conditions. After the calculations are completed, the tensile or compressive damage range of the rock retaining wall structure under different working conditions is obtained through the post-processing function of the numerical simulation software. S2. Based on the vulnerable locations and damage degree data of the stone retaining wall structure calculated by numerical simulation software, ultrasonic non-destructive testing methods are used on site to conduct rapid local testing regularly to more accurately identify the damage degree of the stone retaining wall structure.

2. The method for monitoring damage of a stone wall structure according to claim 1, characterized in that: The damage factor is defined as follows: Where D is the damage factor of concrete material; W0 is the strain energy density of undamaged concrete material; W ε is the strain energy density of damaged concrete material.

3. The method for monitoring damage of a stone wall structure according to claim 1 or 2, characterized in that: Step S2 specifically includes: The tensile or compressive damage range of the rock-blocking wall structure under different rock-rolling impact conditions is calculated by numerical simulation software, and a corresponding data cloud platform is further constructed to store and call the vulnerable data of the rock-blocking wall structure; At the completion of the rockfall protection project, an ultrasonic detector was used to detect the vulnerable parts of the rockfall wall structure in turn to obtain the initial ultrasonic wave velocity C at the vulnerable parts. 0n and the initial ultrasonic amplitude T 0n ; During the operation of the rockfall protection project, once a rockfall disaster occurs, an ultrasonic detector is used to detect the vulnerable position of the rockfall wall after the rockfall disaster according to the data information of the vulnerable position and degree of vulnerability of the rockfall wall in the data cloud platform, and the ultrasonic wave velocity C of the damage at the vulnerable position is obtained. 1n and the damaging ultrasonic amplitude T 1n ; The ultrasonic wave velocity is defined as the damage variable to characterize the damage characteristics of the concrete inside the stone wall under the impact load of rolling stones: Where: D cn is the damage degree at different positions on the stone wall; C 1n is the velocity of the damage ultrasonic wave at different positions on the stone wall; C 0n is the initial post-ultrasonic wave velocity at different positions on the stone wall; The change of ultrasonic amplitude is used as the characteristic parameter of concrete damage, and the ultrasonic wave velocity parameter is used as an auxiliary parameter to jointly evaluate the damage degree of the main structure of the stone retaining wall under the impact load of rolling stones.

4. The method for monitoring damage of a stone wall structure according to claim 1 or 2, characterized in that: The first soft buffer layer of the stone-blocking wall structure is a sand layer, the second soft buffer layer is a foam plastic layer, and the hard buffer layer is a steel plate layer.

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