CN115058993A

CN115058993A - Rockfall prevention method, flexible blocking structure, design method of flexible blocking structure and construction method of flexible blocking structure

Info

Publication number: CN115058993A
Application number: CN202210724809.3A
Authority: CN
Inventors: 王涛; 杨堉果; 范琳琳
Original assignee: Sichuan Communication Surveying and Design Institute Co Ltd
Current assignee: Sichuan Communication Surveying and Design Institute Co Ltd
Priority date: 2022-06-24
Filing date: 2022-06-24
Publication date: 2022-09-16

Abstract

The invention relates to the technical field of rockfall protection, in particular to a rockfall prevention method, a flexible blocking structure, a design method and a construction method of the rockfall prevention structure, wherein a plurality of protection ropes are oppositely penetrated through an upright post at a flat part of a protection area to form a flexible rockfall wall of which the distance is smaller than the diameter of a rockfall block, at least one end part of each protection rope is movably connected with a friction block after passing through the upright post, and the flexible rockfall wall can enable the protection ropes to pull the friction blocks to relatively move under the action of rockfall impact; the invention reduces the impact force of falling rocks by using the friction energy consumption mode of the friction blocks and the ground, and the function of the flexible stone blocking wall can be recovered by recovering the friction blocks to the original positions after the falling rocks are removed, so that the friction blocks do not need to be replaced, and the maintainability is good.

Description

Anti-rock falling method, flexible retaining structure, design method of flexible retaining structure and construction method of flexible retaining structure

Technical Field

The invention relates to the technical field of rockfall protection, in particular to a rockfall prevention method, a flexible blocking structure, a design method and a construction method of the flexible blocking structure.

Background

The passive protection system is characterized in that a fence type flexible blocking net mainly made of a steel wire rope net is arranged at a corresponding position on a slope and used for blocking falling rocks on the slope so as to avoid damaging protected objects. The passive protection system is an effective and economic method for a high and steep side slope with concentrated collapse rockfall occurring regions and high frequency or large difficulty in slope construction operation; the main advantage of passive protection systems compared to active protection systems is that the cleaning work is simple or does not require cleaning.

Compared with a rigid reinforced concrete blocking structure, the flexible blocking net has excellent deformation buffering performance in the aspect of falling rock protection. The existing flexible blocking net mainly comprises a high-strength metal flexible net piece, a support column, a support rope, an anchor pulling rope, an energy consumption device and a corresponding fixed foundation; the flexible blocking net is supported by a plurality of support columns, and is connected with the support columns or slope body anchoring points through support ropes, and meanwhile, in order to improve the protection safety coefficient, an anchor pulling rope is often needed to be connected with the tops of the support columns and anchor rods positioned on the upper side of the slope so as to resist overturning; energy dissipation elements are arranged on supporting ropes or anchor pulling ropes connected with the flexible protective net and used for buffering falling rock impact on the protective net, and kinetic energy of stones is mainly dissipated by the flexible blocking net and an additional energy dissipation device. Such as patent document CN 201821047166.9. The protective structure is provided with a plurality of ropes on the slope-facing side of the flexible blocking net to ensure the stability; however, to domatic complicated, the rockfall square number is big, and rockfall is mostly under the condition of sharp stratum, should not lay too much rope at the side of meeting the slope, and the easy direct pressure of rockfall weight leads to the rope to make the direct inefficacy of blocking net structure because of the pressure-bearing is too big on the rope otherwise, and the rope blocks easily that the rockfall falls into the effective interception region of flexible blocking net.

Moreover, the existing protective structures often need to replace or repair the energy consuming device after bearing a single impact; particularly, when the elastic element is used as an energy dissipation component, such as a tension spring structure in patent application No. CN202122201481.0, the flexible blocking net mainly depends on the elastic energy dissipation component to prolong the rock falling impact time and reduce the peak impact force, so as to avoid the structure from being instantaneously damaged, and convert the rock falling energy by using the elastic potential energy; however, the elastic energy dissipation component has very limited elastic buffering capacity, short buffering action time and low energy conversion rate, and once the tensile capacity of the elastic energy dissipation component cannot bear the rockfall energy, the elastic element cannot be recovered after being stretched and cannot be reused. The conventional energy consumption device is usually replaced only by entrusting a maintenance department to a professional company or self-contained accessories and professionals, the time window before replacement is long, and a passive protection system cannot provide due protection capability in the period, so that great threat is caused to highway operation; even, due to excessive rockfall impact, the anchor pulling rope may be directly broken, and anchoring construction on the slope needs to be performed again. Therefore, the existing passive protection system is generally troublesome to maintain and repair and low in protection energy level.

Disclosure of Invention

The invention aims to: aiming at the problems that the maintainability of a passive protection system in the prior art is poor and energy dissipation elements of the passive protection system need to be replaced again after bearing single rockfall impact, the invention provides a rockfall prevention method, a flexible blocking structure, a design method and a construction method of the flexible blocking structure.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method for preventing falling rocks is characterized in that a plurality of protection ropes are oppositely penetrated through a stand column at the flat position of a protection area to form a flexible stone blocking wall, the distance between the flexible stone blocking wall and the stone falling block is smaller than the diameter of the falling rocks, at least one end part of each protection rope is movably connected with a friction block after passing through the stand column, and the flexible stone blocking wall can enable the protection ropes to pull the friction blocks to relatively move under the impact action of the falling rocks. The flexible stone blocking wall can be formed by arranging protection ropes with the distance smaller than the diameter of a rockfall in parallel or by hanging fine and dense protection nets with the gaps smaller than the diameter of the rockfall between the protection ropes.

According to the rockfall prevention method provided by the invention, the flexible stone blocking wall is arranged at the flat part of the protection area, and a rope does not need to be arranged on the slope-facing side of the stone blocking wall for anchoring, so that an anchor rod is prevented from being arranged on a slope, and the rockfall prevention method is convenient to construct and is safer and more reliable; also avoided simultaneously falling rocks along the slope directly gliding and assault flexible blocking stone wall on, through setting up flexible blocking stone wall in the smooth department of protective area, falling rocks after through long distance friction loss, probably directly stops in blocking stone wall in front, also probably strikes blocking stone wall through jump, rolling mode, compares and sets up perpendicularly and does not need too much to bear falling rocks gravity in the mode blocking stone wall on slope. Furthermore, the protection rope is connected with the upright column in a sliding mode, penetrates out of the upright column and then is connected with the friction block, the protection rope bulges towards the far slope side under the action of falling rock impact, the friction block is drawn to slide to do work, falling rock impact energy is consumed in a friction energy consumption mode between the friction block and the ground, the function of the flexible stone blocking wall can be recovered by recovering the friction block to the original position after the falling rock is removed, the friction block does not need to be replaced, and the maintainability is good.

According to the invention, through adjusting the balance weight of the friction block and the sliding distance of the friction block, the friction acting of the friction block is matched with the falling rock impact energy, so that the purpose of energy consumption can be realized, the friction block can be repeatedly used, the adjustment and maintenance are convenient, the protection energy level is high, and the effect is expected.

As a preferred embodiment, the friction block is arranged on the inclined surface, and the flexible stone blocking wall can overcome the gravity of the friction block and work by friction force simultaneously under the action of falling rock impact.

As a preferred embodiment, at least one end of the protective rope is connected with the elastic buffer, the flexible stone blocking wall can stretch the elastic buffer firstly under the action of falling stone impact to reduce peak impact force so as to avoid instantaneous damage of the structure, and then the friction block is pulled to move relatively to consume impact energy. The both ends of protection rope are best symmetry setting, and elastic buffer and clutch blocks are all connected gradually to the both ends of protection rope promptly.

According to the invention, the friction block consumes energy, the elastic buffer buffers instant impact force, the elastic buffer is prevented from resisting falling rock impact at the cost of material failure, multiple replacement of energy consumption elements is avoided, the falling rock protection energy level is improved, and the environment adaptability is high.

The invention provides a flexible retaining structure for implementing the method for preventing falling rocks, and the specific scheme is as follows: the flexible blocking structure comprises a group of upright post walls, protection ropes are arranged between the upright post walls in a parallel penetrating mode, the protection ropes between the upright post walls are used for blocking falling rocks, the protection ropes are connected with the upright post walls in a sliding mode, and the free ends of the protection ropes are connected with friction blocks used for balancing weights.

According to the flexible blocking structure provided by the invention, the falling rocks can be blocked in a friction energy consumption mode by reasonably adjusting the balance weight of the friction block and the distance between the friction block and the upright post wall, the structure is simple, the protection capability can be adjusted according to the actual working condition, and the flexible blocking structure can be well suitable for the falling rocks protection with high energy level; and maintenance is simple, and after the friction block shifts because of falling rock impact every time, the next impact can be continuously borne through mechanical reset, namely the friction block has good reusability, and the protection rope can improve the impact resistance through thickness adjustment and material replacement, and the maintainability is high. The flexible blocking structure has good applicability and popularization and application values.

It should be noted that the setting quantity of the protection ropes and the arrangement distance between the protection ropes can be reasonably selected according to the rockfall jump height and the rockfall block diameter, so that the protection ropes can intercept large rockfall, the protection nets can be further hung on the protection ropes, all the protection ropes are connected into a whole combined action, the effect of intercepting broken stones is achieved, and the specific setting is adjusted according to the requirements of practical application scenes.

As a preferred embodiment, the upright post wall is provided with a pulley assembly, the pulley assembly comprises a vertical pulley and a transverse pulley, the arc surface section of the vertical pulley is arranged in a crossed manner corresponding to the arc surface section of the transverse pulley, the transverse pulley is used for supporting the protection rope, and the vertical pulley is used for bearing the protection rope. The transverse pulleys and the vertical pulleys have a guiding function on the protection rope, so that the abrasion of the protection rope is reduced; under the impact of falling rocks, the protective rope that wears to establish on the horizontal pulley can pass through and accept on the cambered surface section of vertical pulley.

As a preferred embodiment, the upright column wall is provided with a channel for the protective rope to penetrate through, the pulley assembly is positioned in the middle of the channel, and two ends of the channel are in gradually-changed and enlarged shapes, such as a conical hole, a horn-shaped hole and the like; or, pulley assemblies are respectively arranged at the inlet and the outlet of the channel, so that the protection rope is prevented from contacting with the corner of the upright column wall, and abrasion is reduced.

In a preferred embodiment, the friction blocks are located away from the slope side relative to the stud wall.

As a preferred embodiment, the free end of each protective rope is correspondingly connected with one friction block, and all the friction blocks positioned on the same side of the upright post wall are arranged in parallel on a plane, so that the adaptability is good. Each friction block can be set to the same structure and have the anchor point of the same height, also can adjust the shape, volume, height, anchorage ground position etc. that correspond the friction block according to the actual demand that the protection rope was shocked resistance.

As a preferred embodiment, the free end of the protective rope is provided with an elastic buffer, and the elastic buffer is connected with a friction block to improve the protective energy level of the flexible retaining structure.

As a preferred embodiment, the upright post wall is provided with a protection part at the backer side, the size of the longitudinal section of the protection part from the backer side to the far-mountain side is gradually increased, the size of the cross section of the protection part is gradually increased from top to bottom in a small-to-large manner, the frontal impact area is reduced, falling rocks are conveniently guided to fall into a protection rope intercepting area, the damage degree of the upright post wall is reduced, and therefore structural failure is avoided; and set up like this and can make the focus of stand wall to the rear lower side, stability of shocking resistance is better. The protection part is an integral structure of the upright post wall, and the protection part is a front end structure which is close to the mountain side relative to the protection rope on the upright post wall.

As a preferred embodiment, the anchor rod is arranged in the column wall and connected with a stable stratum, so that the structural stability of the column wall is enhanced.

In a preferred embodiment, the friction block is positioned on the inclined ground, and the plane position of the friction block is lower than that of the upright column wall, so that the friction force is increased.

As a preferred embodiment, the friction block is a concrete block, has high structural strength and rigidity, and is not easy to damage.

On the other hand, the invention provides a design method based on the retaining structure, which comprises the following steps:

determining the construction position of the blocking structure;

according to the position height of a rockfall area to be protected by the blocking structure, acquiring impact energy of the rockfall at the position reaching the blocking structure;

according to the calculated falling rock impact energy, on the basis that the falling rock impact energy can be converted into the friction block to generate friction work, the relationship between the friction block counter weight and the distance between the friction block and the upright column wall is obtained according to the law of energy conservation, and the parameter design of the friction block counter weight or the distance between the friction block and the upright column wall is obtained.

As a preferred embodiment, the weight M of the pad and the horizontal distance L of the pad from the stud wall are obtained by the following relationship:

ML≥KE/(2μ+gtanα)，E=mgh；

wherein M is the mass of the rock, mu is the friction coefficient between the friction block and the ground, M is the mass of the friction block, L is the horizontal distance from the friction block to the upright column wall, g is the gravity acceleration, h is the height difference from the initial position to the position where the rock impacts the protection rope, K is the design safety coefficient, E is the falling rock impact energy, and alpha is the included angle between the slope surface of the motion path of the friction block and the horizontal plane.

The invention provides a construction method based on the retaining structure, which comprises the following steps:

determining the construction position of the blocking structure, determining the arrangement interval of the upright post walls according to the falling rock impact range, and constructing the upright post walls;

the protection ropes are oppositely penetrated between the upright post walls, the end parts of the protection ropes are connected with the friction blocks after penetrating through the upright post walls, and the protection ropes are sequentially connected with the friction blocks from near to far from the opposite side slope side from bottom to top.

As a preferred embodiment, the construction method further includes a step of hanging a steel wire mesh between the protection ropes.

In a preferred embodiment, before the stud wall is constructed, the construction ground is leveled, and the stud wall is vertically arranged.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. the invention reduces the impact force of falling rocks by using the friction energy consumption mode of the friction blocks and the ground, and the function of the flexible stone blocking wall can be recovered by recovering the friction blocks to the original position after the falling rocks are removed, so that the structure is not damaged in the energy consumption process, the friction blocks are not required to be replaced, the flexible stone blocking wall has good reusability and good maintainability.

2. According to the invention, the friction block is enabled to perform friction work to consume falling rock impact energy by adjusting the friction block counter weight and the friction block sliding distance, the adjustment and maintenance are convenient, the buffering capacity is adjustable, the protection energy level is high, and the effect is expected.

3. The invention adopts the protection rope to intercept the falling rocks, the thickness of the protection rope can be adjusted, and the material can be replaced to adapt to different falling rock impact forces, thereby obviously improving the maintainability of the stone blocking structure.

4. According to the invention, the vertical pulleys and the transverse pulleys are arranged in a crossed manner, so that the device can be used for guiding the protection rope and bearing the steering direction of the protection rope, the stress concentration at the turning part of the protection rope is small, and the friction and the abrasion can be obviously reduced.

5. The invention has simple structure, clear stress path, better applicability and popularization and application value.

Drawings

Fig. 1 is a schematic elevational view of a flexible retaining structure according to example 2.

Fig. 2 is a schematic elevational view of another flexible retaining structure of example 2.

Fig. 3 is a schematic plan view of the flexible retaining structure of example 2.

Fig. 4 is a side view of the flexible retaining structure of example 2.

Fig. 5 is a schematic plan view of the flexible stone barrier wall of example 2 impacted by falling rocks.

Fig. 6 is a schematic structural view of the pulley assembly with the protective rope inserted therein.

Fig. 7 is an elevation view of the flexible stone blocking wall in the embodiment 3, when the pulley assemblies are arranged on the through holes of the upright column wall.

Fig. 8 is a side view of the flexible stone barrier wall of example 3 (friction blocks omitted).

Fig. 9 is a schematic plan view of a flexible stone barrier wall according to example 3.

Fig. 10 is an elevation view of the flexible stone barrier wall of example 4.

Fig. 11 is a schematic view of the pulley assembly arrangement of embodiment 4.

FIG. 12 is a schematic structural view showing that the protective rope is connected with the friction block through the elastic buffer in embodiment 5.

Fig. 13 is a schematic structural view of a stud wall in embodiment 6.

Fig. 14 is a top view of fig. 13.

FIG. 15 is a flow chart of a design of a flexible retaining structure.

An icon: 1-falling rocks; 2-a friction block; 3-protective ropes; 4-column walls; 5-vertical pulleys; 6-a transverse pulley; 7-an elastic buffer; 8-anchor rod.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

A method for preventing falling rocks is characterized in that a plurality of protection ropes are oppositely penetrated through a stand column at a slope toe leveling position of a protection area to form a flexible stone blocking wall with the distance smaller than the diameter of a falling rock block, at least one end part of each protection rope is movably connected with a friction block after passing through the stand column, and the flexible stone blocking wall can enable the protection ropes to pull the friction blocks to relatively move under the action of falling rock impact. The flexible stone blocking wall can be formed by arranging protective ropes with the distance smaller than the diameter of a rockfall, and can also be formed by hanging fine protective nets with the gaps smaller than the diameter of the rockfall between the protective ropes.

According to the method for preventing falling rocks provided by the embodiment, the flexible stone blocking wall is arranged at the flat part of the protection area, and a rope does not need to be arranged on the slope-facing side of the stone blocking wall for anchoring, so that anchor rods are prevented from being arranged on the slope, and the method is convenient to construct and is safer and more reliable; meanwhile, the falling rocks are prevented from directly sliding down along the slope and impacting the flexible stone blocking wall, the flexible stone blocking wall is arranged at the flat part of the protection area, the falling rocks can directly stop in front of the stone blocking wall after long-distance friction loss, and the falling rocks can also impact the stone blocking wall in a jumping and rolling mode, so that the stone blocking wall does not need to bear the gravity of the falling rocks more than the stone blocking wall vertically arranged on the slope; furthermore, the protection rope is connected with the stand column in a sliding mode and penetrates out of the stand column to be connected with the friction block, the protection rope bulges towards the far slope side under the action of falling rock impact and pulls the friction block to slide to do work, falling rock impact energy is consumed in a mode of sliding friction between the friction block and the ground, the function of the flexible stone blocking wall can be recovered by recovering the friction block to the original position after the falling rock is removed, the friction block does not need to be replaced, and the maintainability is good. The friction block should have sufficient strength and rigidity.

According to the invention, by adjusting the balance weight of the friction block and the sliding distance of the friction block, the friction acting of the friction block is matched with the rockfall impact energy, so that the purpose of energy consumption can be realized, the adjustment and maintenance are convenient, the protection energy level is high, and the effect is expected.

Further, in this embodiment, preferably, two ends of the protection rope respectively movably penetrate through the upright post, and the two sides are correspondingly connected with the friction blocks; the friction blocks are arranged on the inclined surface, the advancing resistance of the friction blocks can be increased by adopting modes of slope placing, foundation pit excavation and the like on two sides of the flexible stone blocking wall, so that the energy consumption of falling rocks is increased, and the flexible stone blocking wall can overcome the gravity of the friction blocks and apply work and the friction force to apply work simultaneously under the action of falling rocks impact; or the end part of the protective rope penetrating through the upright post is connected with the elastic buffer, so that the flexible stone blocking wall can firstly enable the elastic buffer to act and then pull the friction block to move relatively under the action of falling stone impact. On the basis of friction energy consumption of the friction blocks, the impact energy of falling rocks under different working conditions can be further adapted through multiple modes, the environment adaptability is improved, the energy protection level is improved, and the stability and safety performance of slope protection are ensured. Optionally, one end of the protective rope can be anchored, and the other end of the protective rope can movably penetrate through the upright post to be connected with the friction block.

Example 2

Based on embodiment 1, this embodiment provides a flexible retaining structure for implementing the above-mentioned rock fall prevention method. As shown in fig. 1-5, the flexible retaining structure is mainly composed of three parts, namely a protective rope 3, a column wall 4 and a friction block 2, specifically:

in the embodiment, two upright column walls 4 are preferably arranged, the groups of the upright column walls 4 are arranged in a straight line facing the side slope, the upright column walls 4 are arranged at a gentle position, the self-stability capability of the upright column walls 4 is utilized to keep the structure of the system stable, the materials can adopt a reinforced concrete structure, and the embedding requirement of the reinforced concrete structure refers to the specification of the retaining wall. The stand wall 4 sets up the trompil, and trompil quantity is unanimous with the protection rope row number, and protection rope 3 wears to establish through 4 trompils of stand wall, connects the both ends respectively and is used for the clutch blocks 2 of counter weight, forms the netted stone structure that blocks of level between stand wall 4. Determining the number of the protective ropes 3 and the vertical arrangement distance according to the block diameter and the impact force of the rockfall 1 to be protected, wherein the minimum distance is not smaller than 20 cm; in order to prevent small-diameter broken stones, a fine protective net can be further hung on the protective ropes 3 between the upright post walls 4 to improve the intercepting effect, and specific settings are selected according to actual application scenes as shown in fig. 2. The protective rope 3 in the embodiment preferably adopts a steel wire rope with the tensile strength of 1870Mpa, has high structural strength and strong toughness, is not easy to damage, and can also adopt an unbonded steel strand with the tensile strength of 1860 Mpa; the friction blocks 2 are of a hexahedral concrete structure, and two ends of each steel wire rope are respectively connected with one steel wire rope to form a group; the upright column wall 4 is of a reinforced concrete structure, has high structural strength and high rigidity, can be a long and narrow columnar body, is deeply buried at the bottom and is connected with a stable bottom layer in an anchoring manner, can also be of a right-angled terrace structure and the like, has good anti-overturning performance, can be cast-in-place constructed and prefabricated and formed in a field, and is specifically arranged according to the scale energy level selection of 1 falling rock.

The protective rope 3 is connected with the upright post wall 4 in a sliding mode, and the protective rope 3 is pulled and tightened through the friction blocks 2 on the two sides. Each protective rope 3 is preferably correspondingly connected with a group of friction blocks 2, and the friction blocks 2 on the same side of two sides of the upright post wall 4 are placed on the ground side by side. The stressed steel wire rope deforms to pull the friction block to move, and the friction block which is not impacted keeps in place.

After the falling rocks 1 impact the steel wire rope net, the counterweight friction blocks 2 on the two sides are drawn, and the purpose of consuming the impact energy of the falling rocks 1 is achieved by the sliding of the friction blocks 2; in the process, the steel wire rope can slide relative to the upright post wall 4 to adapt to deformation, the steel wire rope mainly applies transverse thrust (parallel to the falling rock impact direction) to the upright post wall 4 for supporting the flexible stone blocking structure, the transverse thrust is small, longitudinal force (parallel to the sliding direction of the protective rope) on the steel wire rope is basically offset by a friction block, and the upright post wall has large enough self-stability capacity, high supporting strength and good stability. Through 2 counter weights of reasonable setting clutch blocks and sliding distance for 1 initial to stop motion impacting the wire rope net of falling rocks, relative movement can take place and stop motion before 4 striking stand walls with the construction face for clutch blocks 2. The retaining structure can effectively avoid the problem that energy consumption parts are out of work and need to be replaced again, the energy consumption process is not damaged to the structure, after the retaining structure in the embodiment is impacted by falling rocks 1, the friction block 2 can be restored to the original position by using an excavator or a bulldozer, namely, the function of flexibly intercepting the falling rocks 1 by the retaining structure is completely restored, and the maintenance time is short.

Above-mentioned retaining structure has better expansion function: when the actual falling rocks 1 are large in scale and the protective capability of the flexible wall of the blocking structure is insufficient, the protective capability can be increased by increasing the counter weight of the friction block 2 and adjusting a single steel wire rope with a single hole into a plurality of steel wire ropes; the ground of the friction section can be made into an outward tilting type, so that the friction energy consumption capability is increased, the adaptability is strong, and the adjusting performance is good. Moreover, the thickness, the length and the material of the protective rope 3 in the retaining structure can be adjusted to adapt to different falling stone 1 impact forces, and the maintainability of the retaining structure is obviously improved.

Example 3

Based on embodiment 2, the protection rope 3 is in rigid contact with the pillar wall 4 after being impacted by the falling rocks 1 and forms a turning angle at the end of the penetrating channel, and in order to reduce the wear degree of the steel wire rope, as shown in fig. 6 to 9, in this embodiment, a pulley assembly is arranged in the penetrating channel of the pillar wall 4 through which the protection rope 3 penetrates and is used for receiving the protection rope 3, so as to prevent the protection rope 3 from directly contacting with the rough hole surface of the pillar wall 4. The setting height of the pulley component is matched with the height of the corresponding protective rope 3.

Specifically, as shown in fig. 6, the pulley assembly includes a vertical pulley 5 (with an axis set vertically) and a horizontal pulley 6 (with an axis set horizontally) which are arranged in a staggered manner, the arc-shaped sections of the vertical pulley 5 are arranged in a cross manner corresponding to the arc-shaped sections of the horizontal pulley 6, and the steel wire rope slides along the vertical pulley 5 or the horizontal pulley 6 after being stressed; the axis of rotation both ends of horizontal pulley 6 and the axis of rotation both ends of vertical pulley 5 are all pre-buried in the 4 concrete of stand wall, and horizontal pulley 6 is used for supporting protection rope 3, and vertical pulley 5 sets up in the side slope side of keeping away from of protection rope 3 for block protection rope 3, horizontal pulley 6 and vertical pulley 5 still have the guide effect. Under the impact action of the falling stones 1, the protection ropes 3 which are originally positioned on the cambered surface sections of the transverse pulleys 6 can roll to the cambered surface sections of the vertical pulleys 5 along the cambered surfaces, the motion tracks of the protection ropes 3 are smoothly accepted, and the friction is small.

Referring to fig. 7, the pulley assembly in this embodiment is disposed in the middle of the channel, and the vertical pulley 5 and the horizontal pulley 6 are disposed in close proximity; further, the exit end and the entry end that upright post wall 4 wore to establish the passageway all are the gradual change and enlarge the shape from inside to outside, like toper trompil or tubaeform trompil etc. avoid sharp-pointed right angle, can better adapt to 3 turns of protection rope, reduce 3 wearing and tearing of protection rope. Optionally, a plurality of transverse pulleys 6 and a plurality of vertical pulleys 5 may be alternately arranged in the passage in the upright column wall 4, or pulleys with other arrangement angles may be additionally arranged according to actual conditions.

The protection rope 3 wears to locate on horizontal pulley 6, and two upright walls 4 that the both ends of protection rope 3 worn out the outside respectively are connected with clutch blocks 2 again, and every protection rope 3 corresponds and connects a set of clutch blocks 2. As shown in fig. 8, the friction blocks 2 closest to the slope side are aligned with the upright post walls 4 side by side, and the friction blocks 2 of the other groups are arranged far away from the slope side relative to the upright post walls 4, so that the connecting line between the anchoring end of the friction block 2 and the threading outlet end of the upright post walls 4 and the connecting line between the upright post walls 4 form an obtuse angle, and the included angle between the anchoring end of the friction block and the connecting line is matched with the vertical pulley 5 arranged at the far mountain side of the protection rope 3, thereby being beneficial to reducing the abrasion degree of the steel wire rope in the protection process.

Considering that the falling rocks 1 are hit on the wire rope net in a bouncing and rolling manner due to the reasons of landforms, the shapes of the falling rocks 1 and the like when the falling rocks arrive at the blocking structure, the probability that the bottom protection ropes 3 are directly impacted is smaller, in the embodiment, the protection ropes 3 at the bottom layer are preferably connected with the friction blocks 2 closest to the side slope, and the protection ropes 3 are correspondingly and sequentially connected with the rest friction blocks 2 from bottom to top, so that the friction blocks 2 correspondingly connected with the protection ropes 3 with concentrated upper stress have longer-distance sliding work, the friction energy consumption effect is more remarkable, and the blocking structure is more reasonable in stress. As shown in fig. 9, it is assumed that four layers of protection ropes 3 are arranged on the stud wall 4, the bottommost layer (as the first layer) of protection ropes 3 is connected with the friction blocks 2a1 and B1, the upper layer (i.e., the second layer) of protection ropes 3 is connected with the friction blocks 2a2 and B2, the upper layer (i.e., the third layer) of protection ropes 3 is connected with the friction blocks 2A3 and B3, and the top layer (i.e., the fourth layer) of protection ropes 3 is connected with the friction blocks 2a4 and B4.

Example 4

Compared with embodiment 3, as shown in fig. 10, in the flexible blocking structure provided by this embodiment, a set of pulley assemblies is respectively disposed at the entrance and exit sides of the upright column wall 4 through which the protection rope 3 passes, so as to receive the protection rope 3, and prevent the protection rope 3 from directly contacting with the rough hole surface of the upright column wall 4. The setting height of the pulley component is matched with the height of the corresponding protective rope 3.

Specifically, as shown in fig. 11, each pulley assembly includes two vertical pulleys 5 and one transverse pulley 6, the two vertical pulleys 5 are respectively and oppositely disposed at two ends of the transverse pulley 6, the arc-shaped sections of the vertical pulleys 5 are disposed in a cross manner corresponding to the arc-shaped sections of the transverse pulley 6, an included angle of 90 degrees is preferably formed between the rotation axis of the vertical pulley 5 and the rotation axis of the transverse pulley 6, and the rolling directions of the vertical pulleys 5 and the transverse pulley 6 are the same as the stretching direction of the protection rope 3; the transverse pulley 6 and the two vertical pulleys 5 are packaged in a packaging shell, and a hole for the protective rope 3 to go in and out is reserved on the packaging shell. The pulley assemblies are prefabricated into finished products, so that construction is facilitated, and the abrasion-proof construction of the upright column wall 4 is simplified. Wherein, the transverse pulley 6 in the pulley assembly is used for supporting the protection rope 3 and blocking the protection rope 3, and the transverse pulley 6 and the vertical pulley 5 also have guiding function.

During the installation, wear to establish exit side, the entrance side of protection rope 3 with loose pulley assembly installation or pre-buried in stand wall 4, the discrepancy hole on the loose pulley assembly packaging shell with 3 wear to establish the position with protection rope and correspond to set up the 6 positions of horizontal pulley below 3 corresponding to protection rope.

The friction blocks 2 on the same side of the retaining structure can be respectively arranged on the mountain leaning side and the mountain far side relative to the position of the upright column wall 4. The friction block 2 connected with the protective rope 3 with concentrated stress on the middle layer is arranged side by side with the upright post wall 4, the anchoring height of the friction block 2 is consistent with the arrangement height of the protective rope 3 connected with the friction block, so that the protective rope 3 linearly draws the friction blocks 2 at two ends, the force transmission loss is small, the friction block 2 can be effectively drawn to perform friction energy consumption, and the damage probability of the protective rope 3 is reduced; the other protective ropes 3 are connected in sequence. The protection rope 3 that all the other clutch blocks 2 are connected can be through 5 abrasionproof losses of the vertical pulley in both sides in the loose pulley assembly, and each clutch block 2 can set up to the same specification size.

Under 1 impact action of falling rocks, the protection rope 3 that is in on the cambered surface section of horizontal pulley 6 can roll to the cambered surface section of the vertical pulley 5 of any side of pulley assembly along the cambered surface on the outlet side of stand wall 4, and the smooth motion track of accepting protection rope 3, the damage of turn department is little.

Alternatively, the prefabricated pulley assembly can be provided with only one vertical pulley 5 and one transverse pulley 6; when the protective rope is installed or embedded at two ends of the upright post wall 4, the vertical pulleys 5 are arranged at the far mountain side of the protective rope 3.

Example 5

Further, this embodiment is further improved on the basis of embodiment 2, as shown in fig. 12, and the main difference is that the flexible retaining structure provided in this embodiment is provided with an elastic buffer 7 at the free end of the protective rope 3 for reducing the peak impact force, the elastic buffer 7 is connected to the friction block 2, and the friction block 2 is used as an energy consuming device for consuming the rock fall impact energy, so as to increase the protection grade of the retaining structure; the elastic buffer 7 can be an extension spring, and can be replaced by other buffer devices, such as a pressure reducing ring in CN 202022174263.8. Specifically, the method comprises the following steps:

the flexible retaining structure provided by the embodiment comprises a plurality of protective ropes 3, a group of upright post walls 4, a plurality of groups of friction blocks 2 and a plurality of elastic buffers 7. Upright post wall 4 sets up relatively, wears to be equipped with many protection ropes 3 between the upright post wall 4 side by side, and protection rope 3 forms the flexible protection network that is used for intercepting rockfall 1, and protection rope 3 and upright post wall 4 sliding connection, protection rope 3 wear out and connect elastic buffer 7 behind upright post wall 4, and elastic buffer 7 can dismantle connection clutch blocks 2. The friction blocks 2 correspondingly connected with each protection rope 3 are stacked along the down-slope direction, the friction block 2 group closest to the side of the side slope is arranged in parallel and aligned with the upright post wall 4, the friction blocks 2 of the other groups are arranged opposite to the upright post wall 4 and far away from the side slope, so that the connecting line between the anchoring end of the friction block 2 and the threading outlet end of the upright post wall 4 and the connecting line between the upright post walls 4 form an obtuse angle; correspondingly, in order to reduce the abrasion degree of the steel wire rope in the protection process, at least two pulleys are pre-embedded in a passage of the upright column wall 4 penetrating through the protection rope 3, the rotation direction of the pulleys is consistent with the arrangement direction of the protection rope 3, at least one pulley is used for supporting the protection rope 3, and one pulley can be used for guiding the protection rope 3 to incline forwards and stretch due to impact, so that the abrasion between the pulley and the upright column wall 4 is reduced; the included angle formed between the rotating shafts of the adjacent pulleys can be used for the protective rope 3 to penetrate through. The exit end and the entry end of the upright post wall 4 penetrating the channel are both set to be smooth cambered surfaces, so that the sharp corner is prevented from increasing abrasion.

When the falling rocks 1 impact the steel wire rope net, the steel wire ropes firstly stretch the elastic buffer 7, if the impact energy of the falling rocks 1 is small enough, the protection purpose of buffering the impact of the falling rocks 1 can be achieved after the first-stage energy consumption of the elastic buffer 7, and a maintainer can directly replace the failed elastic buffer 7 on the protection rope 3 without influencing a stone blocking structure between the upright post walls 4; if the impact energy of the falling rocks 1 is large enough, after the peak impact force is reduced through the elastic buffer 7, the energy is consumed through the second-stage friction of the traction friction block 2, the protection level is high, and the falling rocks impact can be better adapted.

Example 6

As a specific embodiment, the stud wall 4 of the above examples 2-5 is also designed to resist the impact of falling rocks 1. Specifically, as shown in fig. 8, 10, 13, and 14, the front end of the upright post wall 4 on the side of the mountain is formed in a gentle slope shape, and the gentle slope shape gradually converges from the middle to both sides. Specifically, the stud wall 4 includes a protection portion, and the protection portion is arranged from small to large in a gradually-changing manner from the longitudinal section of the backer side to the longitudinal section of the distal side, and the cross sectional dimension of the protection portion is gradually increased from top to bottom. On 1 striking to upright post wall 4 of falling rock, upright post wall 4 can be with the inboard reposition of redundant personnel direction of falling rock 1, avoids 1 front striking upright post wall 4 of falling rock to cause the damage. An anchor rod 8 is obliquely arranged in the upright column wall 4 along the gentle slope, and the anchor rod 8 is obliquely connected with a stable stratum to strengthen the anti-overturning capability of the upright column wall 4.

Alternatively, the planar shape of the stud wall 4 may also be trapezoidal, triangular, or the like.

Example 7

Based on the flexible retaining structure provided in embodiment 2, this embodiment provides a design method of the above retaining structure. Specifically, as shown in fig. 2 and fig. 15, the method includes the following steps:

step one, acquiring data information such as falling rock impact range, falling rock block diameter, falling rock energy and the like to be protected according to a geological survey report. Determining whether a steel wire mesh is additionally arranged on the steel wire rope or not according to the particle size of the block stone: the falling rocks are mainly large blocks, if the diameter of the falling rocks is larger than 0.3m, a steel wire mesh is not additionally installed, otherwise, the falling rocks are additionally installed.

And secondly, selecting a proper construction position according to the site terrain conditions, acquiring the motion track information between the falling rocks and the flexible stone blocking wall, such as the rolling gradient, the rolling path/height, the falling rock jumping height at the position of the stone blocking wall and the like, and calculating the falling rock impact force at the position where the blocking net is supposed to be arranged.

Selecting to arrange a stand column wall on a gentle and stable ground; the position of the stone blocking wall and the distance between the upright post walls are determined according to the falling stone impact range, the height of the flexible stone blocking wall (namely the arrangement height of the steel wire ropes) is determined according to the falling stone jumping height of the position of the stone blocking wall, and the vertical distance between the steel wire ropes and the number of the steel wire ropes are determined by combining the falling stone impact force and the falling stone block diameter, so that the specific setting scheme of the blocking structure is comprehensively obtained, the size of the flexible stone blocking wall formed between the upright post walls can be adapted to the falling stone impact range, and the falling stones are effectively blocked.

And step three, configuring friction blocks according to the number of the steel wire ropes, wherein two ends of each steel wire rope are respectively connected with one friction block, and the balance weight of each friction block is determined by calculation according to the impact force borne by the steel wire rope. Wherein the design safety factor K of the steel wire rope and the friction block counterweight is 2.0.

The falling rock protection model is simplified, the falling rock is assumed to be a regular rock body, the slope gradient of the slope is basically consistent, the slope body does not generate plastic deformation and elastic deformation, and according to the law of energy conservation, in the process that the falling rock rolls from a high position to the position of the stone blocking wall, gravitational potential energy is converted into energy such as kinetic energy and rotational energy. At the position of the stone blocking wall, the calculation formula of the falling rock impact energy can refer to relevant specification requirements, such as:

energy calculation: total kinetic energy = kinetic + rotational energy, i.e. E =1/2mv ₀ ² +1/2Iw ² ；

Wherein, m-rock mass (kg), v ₀ Rock pre-impact velocity (m/s), I-moment of inertia (kgm) when rock rolls ² ) W-angular velocity(s) of rock rotation before impact ^-1 ）。

The formula can be simplified as: e ≈ 1.2 × 1/2mv ₀ ² ；m=δV；

Wherein m-rock mass (kg), δ -density of rock (kg/m) ³ ) V-volume of rock (m) ³ ）。

Therefore, can be formed by E = mgh ≈ 1.2 × 1/2mV ₀ ² Obtaining the instantaneous velocity v when the rock impacts the steel wire rope ₀ (ii) a And h is the height difference from the initial position of the falling rocks to the position of the stone blocking wall.

In the process from the time of falling rock impacting a steel wire rope to the time of stopping the movement of the falling rock, the kinetic energy of the falling rock is converted into the kinetic energy of the steel wire rope to pull friction blocks at two sides to slide towards the position of a vertical column wall to do work (other energy exchange modes in the middle process are negligible), in order to consume the falling rock impact energy by utilizing the friction block friction work mode as much as possible, the friction block has proper weight, so that the static friction force which can be generated between the friction block and the ground is smaller than or equal to the initial tension of the steel wire rope on the friction block, and the friction block and the vertical column wall are kept with enough safety distance to stop the movement of the falling rock before the friction block impacts the vertical column wall. And if the transmission energy loss of the steel wire rope in the middle is not counted, calculating and determining the safety distance L set by the friction block according to the maximum falling rock impact energy. Under the condition that the adjacent friction blocks are not in contact with each other, the following formula is adopted:

KE≤μ（Mgcosα）×2L/cosα+Mg×Ltanα，

obtaining ML more than or equal to KE/(2 mu + gtan alpha),

wherein K is the design safety factor, E is the falling rock impact energy, and g is the acceleration of gravity (m/s) ² ) M is the mass (kg) of the friction block, mu is the friction coefficient between the friction block and the ground, L is the horizontal distance between the friction block and the upright post, and alpha is the included angle between the slope surface of the motion path of the friction block and the horizontal plane. Meanwhile, the friction block has enough weight to prevent the steel wire rope from drawing the friction block to impact the upright column wall under the action of falling rock impact energy. According to the actual working conditions, when one parameter is determined, the other parameter can be correspondingly determined; in general, the minimum length of two ends of the steel wire rope exceeding the upright column wall is set to be 2 meters, namely L is 2 m.

Example 8

Based on any one of the embodiments 2 to 6, the present embodiment provides a construction method of the flexible retaining structure, including the following steps:

step one, treating a foundation, selecting proper gentle ground or leveling slope, and cleaning waste residues so as to construct a retaining structure;

and step two, lofting and marking, determining the setting position of the upright column wall, and erecting the prefabricated upright column wall through mechanical equipment such as a crane and the like. The height of the upright column wall is 2m-5m, a plurality of anchor rod through holes are reserved in the upright column wall, and the anchor rods are driven into a stable stratum through the anchor rod through holes and are grouted for reinforcement, so that the relation between the upright column wall and the ground is enhanced; the setting distance of the upright post wall is 3m-5 m. Meanwhile, all the friction blocks can be placed on two sides of the stone blocking wall in parallel by utilizing equipment such as an excavator, the friction blocks are of a hexahedral concrete structure, each friction block is 1t-2.5t heavy, the bottom surface is roughened and thickened, galvanized U-shaped bolts are pre-buried on the friction blocks to serve as anchoring points, and the anchoring points of all the friction blocks are arranged on the side where the upright column wall is located.

And thirdly, penetrating a plurality of protective ropes between the upright column walls, wherein the protective ropes pass through the pulley assemblies on the upright column walls from two sides respectively and penetrate out of the upright column walls to be sequentially connected with the corresponding friction blocks, the interval between every two adjacent protective ropes is 0.3-0.6 m, and two ends of each protective rope respectively extend out of the upright column walls at two sides by 2 m. Specifically, the free end of the steel wire rope is provided with a U-shaped latch, the U-shaped latch is connected with one end of the extension spring, and the other end of the extension spring is hooked on a U-shaped bolt of the friction block, as shown in fig. 12. Then the position of the friction block is adjusted to tighten the protective ropes, and a fine protective net can be hung between the protective ropes to intercept the gravels with small grain sizes.

Example 9

and step two, lofting and marking, determining the setting position of the upright post wall, and casting the upright post wall in situ. Specifically, a foundation pit with a certain depth is excavated at a corresponding position of the upright column wall, the anchor rod is inserted into the stratum, the exposed surface of the reserved part structure is bound with the structural steel bars of the upright column wall, a template is built, a through hole is reserved for penetrating, concrete is poured to form the upright column wall, and pulley assemblies are embedded on two sides of a channel for penetrating the protective rope in the upright column wall. The pulley assembly comprises a transverse pulley and a vertical pulley, the rotating shaft of the transverse pulley is transversely arranged, the rotating shaft of the vertical pulley is vertically arranged, and the cambered surface sections of the transverse pulley and the vertical pulley are respectively arranged corresponding to the protection rope. The height of the upright post wall is 2m-5m, the setting distance is 3m-5m, and the preset perforation distance is 0.3m-0.6 m.

And step three, after the upright column walls are solidified and formed, a plurality of protective ropes are arranged between the upright column walls in a penetrating mode, the protective ropes respectively pass through the pulley assemblies on the upright column walls from two sides and then penetrate out of the upright column walls, and two ends of each protective rope respectively extend out of the upright column walls on the two sides by 2m and are respectively connected with corresponding friction blocks. The friction block weighs 1t-2.5t (ton). Digging a foundation pit at a certain position away from the upright column wall for placing a friction block, and inclining the side wall of the foundation pit; and (4) placing the friction block into the foundation pit by using mechanical equipment, and paying attention to keep the balance of the two sides of the protection rope.

As other possible implementation modes, the foundation can be set on two sides of the upright post wall for slope relief treatment, and the friction blocks are arranged on the inclined slope surface during installation. When frictional force was not enough to offset the rock fall impact force, through with the rubbing block setting realize that frictional force combines the common power consumption of gravity on the inclined plane, provide bigger retaining structure protective capacities, construction convenience is swift.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A method for preventing falling rocks is characterized in that a plurality of protection ropes are oppositely penetrated through a stand column at a slope toe leveling position of a protection area to form a flexible stone blocking wall with the distance smaller than the diameter of a falling rocks, at least one end part of each protection rope is movably connected with a friction block after passing through the stand column, and the flexible stone blocking wall can enable the protection ropes to pull the friction blocks to relatively move under the action of falling rocks impact.

2. The method for preventing falling rocks according to claim 1, wherein the friction block is arranged on the inclined surface, and the flexible stone blocking wall can overcome the gravity of the friction block to do work and the friction force to do work under the impact action of falling rocks.

3. A method as claimed in claim 1 or claim 2, wherein the protective rope has an elastic buffer attached to at least one end thereof, and the flexible barrier wall is adapted to be able to move relative to the friction block by pulling the elastic buffer and then pulling the friction block under the impact of falling rocks.

4. The utility model provides a flexible structure of blocking, its characterized in that includes a set of stand wall (4), wear to be equipped with protection rope (3) on stand wall (4) side by side, between stand wall (4) protection rope (3) are used for intercepting rockfall (1), protection rope (3) with stand wall (4) sliding connection, the clutch blocks (2) that are used for the counter weight are connected to the free end of protection rope (3).

5. A flexible retaining structure according to claim 4, wherein the upright wall (4) is provided with pulley assemblies, the pulley assemblies comprise vertical pulleys (5) and transverse pulleys (6), the positions of the arc sections of the vertical pulleys (5) corresponding to the arc sections of the transverse pulleys (6) are arranged in a cross manner, the transverse pulleys (6) are used for supporting the protection ropes (3), and the vertical pulleys (5) are used for bearing the protection ropes (3).

6. The flexible retaining structure according to claim 5, wherein the upright wall (4) is provided with a passage for the protective rope (3) to pass through, the pulley assembly is located in the middle of the passage, and two ends of the passage are gradually enlarged; or the pulley assemblies are respectively arranged at the inlet and the outlet of the channel.

7. A flexible retaining structure according to claim 4, wherein the friction blocks (2) are located away from the slope side relative to the stud wall (4).

8. A flexible retaining structure according to claim 4, wherein the free end of each protective rope (3) is connected to a corresponding friction block (2), and all the friction blocks (2) on the same side of the upright wall (4) are juxtaposed on a plane.

9. A flexible retaining structure according to claim 4, wherein the free ends of the protective rope (3) are provided with elastic bumpers (7), the elastic bumpers (7) being connected to the friction blocks (2).

10. A flexible retaining structure according to any one of claims 4 to 9, wherein the stud walls (4) are provided with guards on the side of the back, the longitudinal cross-sectional dimension of the guards increasing from the side of the back to the side of the distance, the cross-sectional dimension of the guards increasing from top to bottom.

11. A flexible retaining structure according to any one of claims 4 to 9, wherein anchor rods (8) are provided in the stud wall (4), the anchor rods (8) being connected to a stable ground formation.

12. A flexible retaining structure according to any one of claims 4 to 9, wherein the friction blocks (2) are located on inclined ground and the friction blocks (2) are located in a lower plane than the stud walls (4).

13. A flexible retaining structure according to any one of claims 4 to 9, wherein the friction blocks (2) are concrete blocks.

14. A method of designing a flexible retaining structure according to any of claims 4 to 13, comprising the steps of:

determining the construction position of the blocking structure;

according to the position height of the rock falling area to be protected by the blocking structure, acquiring the impact energy of the falling rocks (1) reaching the blocking structure;

according to the calculated falling rock impact energy, on the basis that the falling rock impact energy can be converted into friction work generated by the friction block (2), the relationship between the friction block counter weight and the distance from the friction block (2) to the upright post wall (4) is obtained according to the energy conservation law, and the parameter design of the distance from the friction block counter weight or the friction block (2) to the upright post wall (4) is obtained.

15. Method of designing according to claim 14, characterized in that the friction block counterweight M and the distance L of the friction block (2) to the stud wall (4) are obtained by the following relations:

ML≥KE/(2μ+gtanα)，E=mgh；

wherein M is the mass of the rock, mu is the friction coefficient between the friction block (2) and the ground, M is the mass of the friction block, L is the horizontal distance between the friction block (2) and the upright post wall (4), g is the gravity acceleration, h is the height difference between the initial position and the position of the rock when the rock impacts the protection rope (3), K is the design safety coefficient, E is the falling rock impact energy, and alpha is the included angle between the slope surface of the motion path of the friction block and the horizontal plane.

16. A method of constructing a flexible retaining structure according to any one of claims 4 to 13, including the steps of:

determining the construction position of the blocking structure, determining the arrangement interval of the upright post walls according to the falling rock impact range, and constructing the upright post walls (4);

to wearing protection rope (3) between stand wall (4), the tip of protection rope (3) passes and connects clutch blocks (2) behind stand wall (4), and protection rope (3) connect gradually relative side slope side from near to distant clutch blocks (2) from bottom to top.

17. The construction method according to claim 16, further comprising the step of hanging a steel wire mesh between the protection ropes (3).

18. Construction method according to claim 16 or 17, characterised in that before the stud wall (4) is constructed, the construction ground is leveled and the stud wall (4) is set vertically.