CN209873819U - Prevention and control structure of ultrahigh steep rock slope system - Google Patents

Abstract

A prevention and control structure for an ultra-high and steep rock slope system, including a natural slope and an engineering slope arranged sequentially from top to bottom. An excavation influence area is set at the inner bottom of the natural slope, and the excavation influence area is located at the front of the engineering slope. Above, the plane range of the excavation affected area is equal to the plane range of the project slope, and the height is 1/10 to 1/5 of the project slope height, and pre-stressed anchor cables are used for pre-anchoring. One or several passive protective nets are installed in the natural slope to prevent small-scale dangerous rocks randomly existing on the entire slope. The slope of the project is excavated in steps. The slope surface of each step project is prevented by hanging net shotcrete. The utility model controls the upper natural slope and the lower engineering slope system, and controls the stress and strain in the affected area of the slope excavation through the active prestress of the anchor cable in advance, prevents the plastic yield zone from further developing to the upper part, and avoids the lower engineering Adverse effects of slope excavation on the upper natural slope.

Description

A system prevention and control structure for ultra-high and steep rocky slopes

technical field

The invention relates to the field of slope engineering prevention and control, in particular to an ultra-high and steep rock slope system prevention structure and method.

Background technique

Slope is a geological body with air condition on the surface of the crust, which is composed of slope top, slope surface, slope foot and rock and soil mass at a certain depth below it. According to the height characteristics of slopes, slopes with a slope height of less than 10m are low slopes, 10m to 30m are medium and low slopes, 30m to 70m are medium slopes, 70m to 150m are high slopes, and 150m to 300m are super high slopes. Slopes above 300m are ultra-high slopes; according to the steepness and gentleness of slopes, those with slopes below 10° are gentle slopes, 10°-30° are slopes, 30°-45° are medium slopes, and 45°-60° are medium slopes. ° is a steep slope, 60°～75° is a steep slope, 75°～90° is an upright slope, and more than 90° is an inverted slope; according to the composition of the slope, it is divided into soil, sand, gravel, block stone, and boulder The soil slope is composed of rock mass with fragmented or fragmented structure, and the rock slope is composed of rock mass with block structure, layered structure, and mosaic fragmented structure.

According to the cause of formation, slopes can be divided into two types: natural slopes and engineering slopes. The naturally existing slopes formed by natural forces are called natural slopes, and the slopes formed by artificial excavation and reconstruction or affected by engineering are called engineering slopes. Generally speaking, there is still a certain height of natural slope above the artificial excavation and reconstruction engineering slope, and the two are interdependent and mutually restrictive, forming a complete slope together. The problem of mutual interference between high and steep rock engineering slopes and their upper natural slopes is particularly prominent. At present, there is a lack of systematic prevention and control methods for ultra-high and steep rocky slopes. The traditional slope prevention and control has the following problems:

1. Excavation of ultra-high and steep rock engineering slopes causes deformation or even instability of the upper natural slope

The height of ultra-high and steep rock slopes is generally hundreds of meters or even more than one thousand meters. In order to arrange the structure of buildings, the engineering slope formed by manual excavation is generally located in the lower part of the slope, and there may be more than a hundred meters or even several kilometers in the upper part. 100 meters of natural slope. Since a large amount of rock mass outside the slope is excavated by the engineering slope, it is equivalent to excavating the support body at the lower part of the slope, which affects the integrity of the slope, which not only adversely affects the stability of the engineering slope, but also affects the upper part of the engineering slope. The overall stability of the natural slope has also had a very negative impact. The traditional super-high and steep rock slope prevention and control structures and methods are generally only for the prevention and control of engineering slopes, without systematic consideration of the overall stability of the upper natural slope of the engineering slope, which may lead to deformation or instability of the upper natural slope, and then threaten The safety of the slope of the lower part of the project may cause incalculable losses to the project.

2. The local stability of the ultra-high and steep rocky natural slope affects the safety of the underlying engineering slope

The local stability of super-high and steep rocky natural slopes is also prominent. There may be local hazards such as blocks or dangerous rocks on it. Under the action of natural factors such as unloading, weathering, and rainfall, rolling and falling rocks may occur. Because the super-high and steep slope is not only high and steep, but also the lower part is the engineering slope. Once the blocks or dangerous rocks on the natural slope roll down or fall from the height, it will directly threaten the construction period and operation of the lower engineering slope. Long-term personnel, equipment and related building safety.

At present, for the prevention and control of ultra-high and steep rock slopes, conventional structures and methods generally only control engineering slopes, and do not systematically consider the mutual interference between the lower engineering slope and the upper natural slope, and the excavation of the lower engineering slope may cause other problems. The upper natural slope is deformed or even unstable, and the local stability of the upper natural slope may affect the safety of the lower engineering slope during construction and operation, and may cause immeasurable losses to personnel, equipment and engineering safety. In view of this situation, a system prevention and control structure and method for ultra-high and steep rocky slopes are developed.

Contents of the invention

In order to solve the above problems, the present invention provides an ultra-high and steep rock slope system prevention and control structure, which better solves the problems of mutual interference between the upper natural slope and the lower engineering slope, which are difficult to solve by conventional prevention and control methods.

The technical scheme adopted in the present invention is: a method for preventing and controlling a super-high and steep rocky slope system, comprising the following steps:

A. Prevention and control of hazards existing in natural slopes:

Natural slope pumice or dangerous stone removal;

Prevention and control of random dangerous rocks on natural slopes: For small-scale dangerous rocks that randomly exist on the entire slope, one or several passive protective nets are selected for prevention and control;

B. Prevention and control of the excavation affected area in the natural slope: before the excavation of the engineering slope, the plane range and height of the excavation affected area in the natural slope shall be determined according to the excavation layout and height of the engineering slope, and the excavation affected area shall be prestressed Anchor cables are pre-anchored;

C. Engineering slope excavation: After the upper natural slope and the prevention and control construction of the excavation affected area are all completed, the lower engineering slope excavation construction will start; the engineering slope should meet the self-stabilization ability, and the engineering slope will be excavated in steps .

D. Engineering side slope support: The engineering side slope support is followed by the excavation of the side slope. After the excavation of the side slope of each step is completed, the slope surface shall be prevented and controlled immediately; according to the engineering side slope structure and rock mass quality conditions 1-2 rows of prestressed anchor cables are used for prevention and control of the first-level slope; for the local instability of the block on the slope, mortar anchors or prestressed anchors or prestressed anchor cables are used for reinforcement.

Preferably, in the step A, the pumice on the natural slope surface is removed manually, and the small-scale dangerous rock is removed by blasting.

Further, in the step A, the prevention and control of the hazards existing in the natural slope also includes:

Local block prevention and control of natural slopes: reinforcement of local unfavorable geological bodies existing in natural slopes;

Prevention and control of local rock mass fragmentation areas on natural slopes: Active protection nets are used for prevention and control of local rock mass fragmentation areas on natural slopes.

Preferably, in the step A, the lowermost passive protection net is arranged at the junction of the natural slope and the engineering slope.

As a preference, in the step B, the plane range (projected range in the horizontal plane) of the excavation-influenced area is equal to the plane range of the engineering slope, and the height of the excavation-affected area is generally 1/10 to 1/5 of the height of the engineering slope .

As a preference, in the step C, the engineering slope excavation slope ratio is not steeper than the rock formation slope ratio.

Preferably, in the step C, the engineering slope is generally excavated in steps, the height of the steps is generally 15m-30m, and a 2m-3m wide horseway is set.

As a preference, in the step D, after the excavation of the side slope of each step section is completed, the slope surface is immediately prevented by spraying concrete with hanging nets.

A prevention and control structure for a super-high and steep rock slope system, comprising a natural slope and an engineering slope arranged sequentially from top to bottom, characterized in that: the inner bottom of the natural slope is provided with an excavation affected area, and the excavation The excavation affected area is located directly above the project slope, and the plane range of the excavated affected area is equal to the plane range of the project slope, and the height is 1/10 to 1/5 of the height of the project slope, and pre-stressed anchor cables are used for pre-anchoring;

The natural slope is equipped with one or several passive protective nets for preventing and controlling small-scale dangerous rocks that randomly exist on the entire slope, and mortar anchors or anchor piles or prestressed anchors for reinforcing local unfavorable geological bodies or prestressed anchor cables, and active protection nets used to prevent local rock mass fracture areas;

The slope of the project is excavated in steps, and the height of the steps is 15m-30m, and a 2m-3m wide horseway is set up. The slope is prevented and controlled by 1-2 rows of prestressed anchor cables; mortar anchors or prestressed anchors or prestressed anchor cables for reinforcing local unfavorable geological bodies are arranged in the slope of the project.

Preferably, the engineering slope should meet self-stabilization capability, and the slope ratio of excavation is not steeper than that of rock formation.

Further, four passive protective nets are arranged in the natural slope, and the lowermost passive protective net is arranged at the junction of the natural slope and the engineering slope, and the height difference between adjacent passive protective nets is 100m to 150m. The height of each passive protective net is 5m.

The beneficial effects obtained by the present invention are: the prevention and control structure and method of the ultra-high and steep rock slope system of the present invention are popularized and applied in the prevention and control of the ultra-high and steep slopes and other parts of the water inlet of the power station on the right bank of the Wudongde Hydropower Station in the Jinsha River. It has solved the problem of mutual interference between the upper natural slope and the lower engineering slope, which is difficult to solve by conventional prevention and control methods. The super-high and steep rock slope system prevention and control structure and method of the present invention have the following outstanding advantages:

(1) The upper natural slope and the lower engineering slope are systematically prevented and controlled, and the prevention and control effect is comprehensive and thorough. By first adopting "high prevention and pre-reinforcement" on the upper natural slope, prevent and control the local block or dangerous rocks and other dangerous sources in the upper natural slope, and pre-reinforce the engineering slope excavation affected area in the natural slope , which completely avoids the mutual interference between the upper natural slope and the lower engineering slope; in addition, "stable excavation and suitable protection" is adopted for the lower engineering slope, and the engineering slope has basic self-stabilization ability by controlling the excavation slope ratio, and Proper protection of the engineering slope ensures the overall stability of the engineering slope.

(2) Pre-anchoring for the affected area of natural slope excavation, taking precautions and precise prevention and control. By adopting the "pre-reinforcement" method for the excavation-affected area of the natural slope, the reinforcement range is 1/10-1/5 of the slope height of the project, and the affected area of the excavation of the slope is controlled by the pre-stressed anchor cable actively applied in advance. stress and strain, prevent the further development of the plastic yield zone to the upper part, and completely avoid the adverse effects of the excavation of the lower engineering slope on the upper natural slope.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Reference signs: 1. Natural slope, 2. Engineering slope, 3. Excavation affected area, 4. Passive protective net, 5. Partial rock crushing area, 6. Partial block, 7. Hanging net shotcrete, 8. Prestressed anchor cables for natural slopes, 9. Prestressed anchor cables for excavation affected areas, 10. Prestressed anchor cables for engineering slopes, 11. Mortar anchors or anchor piles for natural slopes, 51. Active protection nets, s, slope ground line, m, slope excavation line.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the prevention and control structure and method of the ultra-high and steep rock slope system of the present invention, its core is to adopt the concept of system prevention and control of "high prevention and consolidation, stable excavation and suitable protection", and adopt " The prevention and control methods of "high defense" and "pre-consolidation", and the prevention and control methods of "stable excavation" and "suitable protection" are adopted for the slope of the lower part of the project. The following are respectively elaborated:

(1) High defense

"High defense" refers to the prevention and control of dangerous sources such as blocks or dangerous rocks that exist locally on the upper natural slope. According to the scale and distribution characteristics of blocks and dangerous rocks, targeted prevention and control methods are adopted: remove small pumice or dangerous rocks; use mortar anchors, anchor piles or prestressed anchors for larger blocks (cable) for reinforcement (for blocks less than 100 cubic meters, mortar bolts are used for reinforcement, for blocks of 100 to 500 cubic meters, anchor piles are used for reinforcement, and for blocks larger than 500 cubic meters, prestressed anchor cables are used for reinforcement); Active protective nets are used to prevent and control the local rock mass fragmentation area on the slope; passive protective nets are used to prevent and control small-scale dangerous rocks randomly existing on the entire slope, and the lowest passive protective net is set on the adjacent parts of natural slopes and engineering slopes .

(2) Pre-solidification

"Pre-reinforcement" refers to the pre-reinforcement of the area affected by engineering slope excavation within the natural slope. In order to prevent the excavation of the engineering slope from affecting the stability of the natural slope above, before the excavation of the engineering slope, the excavation affected area near the junction of the natural slope and the engineering slope is pre-anchored, and the reinforcement range is the height of the engineering slope 1/10-1/5 of that, the reinforcement measure is to use prestressed anchor cables for anchorage, through the prestressed anchor cables actively applied in advance, to control the stress and strain in the area affected by slope excavation, and to prevent the further development of the plastic yield zone to the upper part In order to prevent the excavation of the lower engineering slope from affecting the stability of the upper natural slope.

(3) steady digging

"Stable excavation" means to make the project slope have basic self-stabilization ability by controlling the excavation slope ratio, and should avoid areas with large faults and weak layers, and special attention should be paid to slopes with unfavorable slope structures such as forward slopes. Downward slope means that the inclination of the rock formation is consistent with the slope aspect of the side slope. The excavation slope of the side slope should be controlled so that the excavation slope is not steeper than the slope of the rock formation layer, so as to avoid excavation causing the layered rock mass on the downside slope to be cut off, resulting in engineering edge Poe has instability problems of his own.

(4) suitable for care

"Suitable protection" refers to proper protection of the engineering slope after excavation. In order to prevent the integrity of the rock mass of the excavated engineering slope from further deteriorating under the action of weathering, the side slope surface is prevented by hanging net shotcrete; according to the engineering slope structure and rock mass quality conditions, the or multi-level slopes, use 1 to 2 rows of prestressed anchor cables for prevention and control; for the relaxation and unloading problems after excavation of engineering slopes and local instability problems such as existing blocks, mortar anchors or prestressed anchors are used (cable) for reinforcement.

A method for preventing and controlling an ultra-high and steep rocky slope system of the present invention, specifically adopts the following steps:

1. Removal of pumice or dangerous rocks on natural slopes: pumice on natural slopes is removed manually, and small-scale dangerous rocks are removed by blasting.

2. Local block prevention and control of natural slopes: Carry out comprehensive and detailed geological identification of natural slopes, investigate in detail local unfavorable geological bodies such as blocks existing in natural slopes, and use mortar anchors, Anchor piles or prestressed anchor rods (cables) and other methods for reinforcement.

3. Prevention and control of local rock mass crushing areas on natural slopes: For local rock mass crushing areas on natural slopes, active protection nets are used for prevention and control.

4. Prevention and control of random dangerous rocks on natural slopes: For small-scale dangerous rocks that randomly exist on the entire slope, one or several passive protective nets are selected for prevention and control according to the height of the slope and the energy level of the passive protective net. Set at the junction of natural slope and engineering slope.

5. Prevention and control of excavation-affected areas in natural slopes: Before excavation of engineering slopes, determine the plane range and height of excavation-influenced areas in natural slopes according to the excavation layout and height of engineering slopes. The plane range is generally slightly larger than the engineering side The height of the slope is generally 1/10 to 1/5 of the height of the project slope, and the prevention and control measures for the excavation affected area are pre-anchored with prestressed anchor cables.

6. Engineering slope excavation: After the upper natural slope and the prevention and control construction of the excavation affected area are all completed, the lower engineering slope excavation will start. The excavation slope ratio of the project slope is not steeper than that of the rock formation, and the slope can meet the basic self-stabilization ability. The slope of the project is generally excavated in steps, the height of the steps is generally 15m~30m, and the width of 2m~3m is set up.

7. Engineering side slope support: The engineering side slope support is followed by the excavation of the side slope. After the excavation of the side slope of each step section is completed, the slope surface is immediately prevented and controlled by hanging net shotcrete; according to the structure of the side slope of the project According to the quality conditions of the rock mass, 1 to 2 rows of prestressed anchor cables are used for prevention and control of first-level slopes or multi-level slopes; for local instability problems such as blocks on the slope, mortar anchors or prestressed anchors are used. Anchor (cable) for reinforcement.

Let's take a real project as an example to illustrate:

The elevation of the top of the ultra-high and steep slope at the right bank of a hydropower station is 1530m, the elevation of the bottom plate of the inlet is 910m, and the elevation of the top of the opening line of the project slope is 1060m. The total height of the slope above the bottom plate of the intake is 620m, the height of the upper natural slope is 470m, and the height of the lower engineering slope is 150m. The problems such as mutual interference between the upper natural slope and the lower engineering slope are very prominent, and the above problems are successfully solved by adopting the prevention method of the present invention. The concrete implementation of this method is introduced below:

1. Removal of pumice or dangerous rocks on natural slopes: pumice on natural slopes is removed manually, and small-scale dangerous rocks are removed by blasting.

2. Local block prevention and control of natural slopes: Carry out comprehensive and detailed geological identification of natural slopes. Through detailed investigation, it is found that there are 25 blocks in natural slopes, of which 8 blocks are L = 6m mortar bolts for prevention and control, 9 blocks using L=12m anchor piles are used for prevention and control, and 1000kN@6m×6m, L=30m prestressed anchor cables are used for prevention and control of 8 blocks.

3. Prevention and control of local rock mass crushing areas of natural slopes: For local rock mass crushing areas of natural slopes, GPS2 type active protection nets are used for prevention and control. The active protection nets cover the entire rock mass crushing area and extend beyond its boundaries to stabilize rock mass Not less than 1m.

4. Prevention and control of random dangerous rocks on natural slopes: For small-scale dangerous rocks that randomly exist on the entire slope, according to the height of the slope and the energy level of the passive protective net, a total of 4 RXI-100 passive protective nets are arranged from top to bottom, respectively Arranged near the elevations of 1500m, 1300m, 1150m, and 1060m, the lowest passive protection net is set at the junction of the natural slope and the engineering slope.

5. Prevention and control of the excavation affected area in the natural slope: the plane range of the excavated affected area is consistent with the project slope, the height is 1/5 of the project slope height, the elevation range is 1060m~1090m, and the excavated affected area is arranged at 1000kN@5m ×5m, L=40m prestressed anchor cable.

6. Engineering slope excavation: After the upper natural slope and the prevention and control construction of the excavation affected area are all completed, the lower engineering slope excavation will start. The excavation slope ratio of transverse slope and oblique slope is 1:0.1, generally a 3m wide horse track is set every 15m; the excavation slope ratio of the forward slope section is 1:0.3, and a 3m wide horse track is generally set every 15m.

7. Engineering side slope support: After the excavation of each level of engineering side slope is completed, the side slope support shall be carried out in time. There are 2 rows on the top of the horse trail at all levels L=9m locking bolts, 5 rows in single-stage slope L=6m system bolt. Set 2 rows of 2000kN＠4.5m×4.5m for each level of slope, L＝40m system anchor cable, hang net shotcrete 12cm on the slope surface, and the parameters of the steel mesh are

It took 30 months to excavate and support the ultra-high and steep slope at the water inlet of the power station on the right bank of the hydropower station. During the construction process, there were no safety accidents, and neither the natural slope nor the engineering slope had obvious deformation, and the prevention and control effect was remarkable.

The basic principles and main structural features of the present invention have been shown and described above. The present invention is not limited by the above examples, and without departing from the spirit and scope of the present invention, the present invention also has various changes and improvements, and these changes and improvements all fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (5)

1. The utility model provides an ultra-high cliff matter slope system prevents and treats structure, includes the natural side slope and the engineering side slope that from top to bottom set gradually, its characterized in that: an excavation influence area is arranged at the bottom in the natural side slope and is positioned right above the engineering side slope; the plane range of the excavation affected area is equal to the plane range of the engineering side slope, the height is 1/10-1/5 of the height of the engineering side slope, and pre-anchoring is carried out by adopting a pre-stressed anchor cable;

one or a plurality of passive protective nets for preventing and controlling small-scale dangerous stones randomly existing on the whole slope are arranged in the natural slope;

the engineering side slope is excavated in terraces, the height of each terrace is 15-30 m, a berm with the width of 2-3 m is arranged, the engineering side slope surface of each stage of terrace is prevented and controlled by adopting net hanging and concrete spraying, and the engineering side slope surface of each stage of engineering is prevented and controlled by adopting 1-2 rows of prestressed anchor cables; and a mortar anchor rod or a pre-stressed anchor cable for reinforcing the local poor geologic body is arranged in the engineering side slope.

2. The ultra-high-steep rocky slope system control structure according to claim 1, wherein: the engineering side slope should meet the self-stability capability, and the excavation slope ratio is not steeper than the rock stratum slope ratio.

3. The ultra-high-steep rocky slope system control structure according to claim 1 or 2, wherein: four passive protective nets are arranged in the natural side slope, and the passive protective net at the lowest part is arranged at the junction part of the natural side slope and the engineering side slope.

4. The ultra-high-steep rocky slope system control structure according to claim 3, wherein: the height difference between the adjacent passive protective nets is 100 m-150 m, and the height of each passive protective net is 5 m.

5. The ultra-high-steep rocky slope system control structure according to claim 1, wherein: and mortar anchor rods or anchor bar piles or prestressed anchor rods or prestressed anchor cables for reinforcing local poor geologic bodies and an active protective net for preventing and controlling local rock mass crushing areas are arranged in the natural side slope.