CN115198793A - Side slope open cut tunnel supporting structure and construction method thereof - Google Patents

Side slope open cut tunnel supporting structure and construction method thereof Download PDF

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Publication number
CN115198793A
CN115198793A CN202210801564.XA CN202210801564A CN115198793A CN 115198793 A CN115198793 A CN 115198793A CN 202210801564 A CN202210801564 A CN 202210801564A CN 115198793 A CN115198793 A CN 115198793A
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open cut
cut tunnel
side slope
tunnel lining
slope
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CN115198793B (en
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周和祥
吴沛沛
姚裕春
周成
李宁
叶世斌
刘宇罡
胡世兴
曾永红
龚建辉
肖昌睿
李伯根
杜猛
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China Railway Eryuan Engineering Group Co Ltd CREEC
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China Railway Eryuan Engineering Group Co Ltd CREEC
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    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D29/00Independent underground or underwater structures; Retaining walls
    • E02D29/045Underground structures, e.g. tunnels or galleries, built in the open air or by methods involving disturbance of the ground surface all along the location line; Methods of making them
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D17/00Excavations; Bordering of excavations; Making embankments
    • E02D17/20Securing of slopes or inclines
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D17/00Excavations; Bordering of excavations; Making embankments
    • E02D17/20Securing of slopes or inclines
    • E02D17/207Securing of slopes or inclines with means incorporating sheet piles or piles
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22Piles
    • E02D5/34Concrete or concrete-like piles cast in position ; Apparatus for making same
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22Piles
    • E02D5/34Concrete or concrete-like piles cast in position ; Apparatus for making same
    • E02D5/46Concrete or concrete-like piles cast in position ; Apparatus for making same making in situ by forcing bonding agents into gravel fillings or the soil
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02ATECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A10/00TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE at coastal zones; at river basins
    • Y02A10/23Dune restoration or creation; Cliff stabilisation

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  • Mining & Mineral Resources (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
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  • General Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Pit Excavations, Shoring, Fill Or Stabilisation Of Slopes (AREA)

Abstract

The invention relates to side slope open cut tunnel support, in particular to a side slope open cut tunnel support structure and a construction method thereof. According to the side slope open cut tunnel supporting structure, side slopes can be prevented from collapsing when excavation foundation pits are excavated and open cut tunnel lining is constructed; the foundation pit excavation and open cut tunnel lining is more convenient. Concrete protective bodies are poured above the open cut tunnel lining, and the open cut tunnel lining can be protected. The guide sliding body and the debris flow materials are discharged from the upper side of the open cut tunnel lining, so that the open cut tunnel structure is protected from landslide and front impact of debris flow, the construction is simple, economic and reasonable, and the application prospect is wide.

Description

Side slope open cut tunnel supporting structure and construction method thereof
Technical Field
The invention relates to a side slope open cut tunnel support, in particular to a side slope open cut tunnel support structure and a construction method thereof.
Background
The land is wide in breadth and varied in terrain, more than 70% of the land is mountainous, hilly and plateau, and the geological conditions are complex, so that landslide, debris flow and other geological disasters are frequent. With the large-scale construction of traffic engineering, many railway and highway lines inevitably pass through landslide and debris flow areas (the surface of a side slope is a covering soil layer, and the lower part of the covering soil layer is bedrock), such as Sichuan-Tibet railways, sichuan-Tibet highways and the like. Although the scale of the high and steep slope shallow landslide and slope debris flow is relatively small, the treatment difficulty is very high due to the characteristics of steep terrain and high position, at present, the method is usually reinforced by adopting a mode of multi-row anti-slide piles and multi-stage anchor cables, and the method has the advantages of large engineering quantity, difficulty in construction, long construction period and poor economy.
Disclosure of Invention
The invention aims to: aiming at the problems of large quantity of reinforcement measures, difficult construction, long construction period and poor economy in the prior high and steep side slope shallow landslide and slope debris flow areas in the background technology, the side slope open cut tunnel supporting structure and the construction method thereof are provided.
In order to achieve the purpose, the invention adopts the technical scheme that:
the utility model provides a side slope open cut tunnel supporting construction, is including setting up the open cut tunnel lining cutting on the side slope, be provided with the high pressure jet grouting reinforcement body in the soil layer of open cut tunnel lining cutting top side slope, open cut tunnel lining cutting top is provided with the concrete protection body, the open cut tunnel lining cutting is kept away from the sub-unit connection of top side slope one end has and is used for supporting the bored concrete pile of open cut tunnel lining cutting, concrete protection body top is provided with the water conservancy diversion slope in the same direction as the side slope direction, the soil layer under the top side slope includes first overburden layer and is located the basement rock of first overburden layer lower part, the one end of high pressure jet grouting reinforcement body is passed first overburden layer and stretch into in the basement rock.
According to the side slope open cut tunnel supporting structure, a high-pressure jet grouting reinforcement body is arranged in a side slope soil layer above a open cut tunnel lining, one end of the high-pressure jet grouting reinforcement body penetrates through the first covering soil layer and extends into the bedrock, so that a pre-reinforcement effect can be achieved on an upper side slope, and the side slope is prevented from collapsing when an excavation foundation pit is excavated to construct the open cut tunnel lining; meanwhile, the high-pressure rotary spraying reinforcing body is moderate in strength and can be broken by an excavator, and excavation construction of the foundation pit is not influenced, so that open cut tunnel lining construction in excavation construction of the foundation pit is more convenient. Concrete protective bodies are poured above the open cut tunnel lining, and the open cut tunnel lining can be protected. The top of the concrete protection body is provided with a guide slope along the slope direction, so that the concrete protection body can play a role in dredging landslide and debris flow, and can guide landslide and debris flow substances to be discharged from the upper side of the open cut tunnel lining when disasters of shallow landslide and slope debris flow occur. The lower part of one end, far away from the upper side slope, of the open cut tunnel lining is connected with a cast-in-situ bored pile for supporting the open cut tunnel lining, and the open cut tunnel lining can be supported and fixed.
The open cut tunnel lining, the concrete protective body, the high-pressure rotary spraying reinforcing body and the cast-in-situ bored pile form an engineering whole fixed on the side slope bedrock together, when a shallow landslide and slope debris flow disaster occurs on a covering soil layer on the upper portion of a side slope, the sliding body and debris flow substances can be guided to be discharged from the upper portions of the high-pressure rotary spraying reinforcing body and the open cut tunnel lining, and the open cut tunnel structure is protected from the positive impact of the landslide and the debris flow.
The structure can ensure the safe operation of railway lines in open cut tunnel lining when disasters such as shallow landslide, slope debris flow and the like occur, and has the advantages of simple construction, economy, reasonability and wide application prospect.
Preferably, a steel guide pipe is further arranged in the soil layer of the upper side slope, one end of the steel guide pipe penetrates through the first soil covering layer and extends into the bedrock, all the steel guide pipes are arranged along the length direction of the open cut tunnel lining, the steel guide pipe is positioned above the high-pressure jet grouting reinforcement body, a reinforcing mesh is laid on the upper surface of the concrete protection body, and the reinforcing mesh is connected with the steel guide pipes.
A side slope open cut tunnel supporting construction, the steel pipe is located high pressure spouts with solid top soon, and high pressure spouts with solid can play good supporting role to the steel pipe of top soon, simultaneously, the steel pipe sets up on high pressure spouts with solid, can spout with solid and play good guard action to high pressure soon. The reinforcing mesh is laid on the surface layer of the concrete protective body, so that the reinforcing mesh can reinforce the concrete protective body, the concrete protective body is prevented from being damaged when the concrete protective body slides on a slope and mud stone flows, the reinforcing mesh is firmly welded with the steel guide pipe, and the integrity of the structure can be enhanced; and ensure the smooth transition between the steel conduit and the guide slope; the top of the concrete protection body is provided with a guide slope along the slope direction, so that the concrete protection body can play a role in dredging landslide and debris flow, and can guide landslide and debris flow materials to be discharged from the steel guide pipe and the top of the open cut tunnel lining when disasters of shallow landslide and slope debris flow occur.
Preferably, the diversion slope and the upper slope form a continuous side slope, and the steel guide pipe, the high-pressure jet grouting reinforcement body, the open cut tunnel lining, the concrete protection body, the reinforcing mesh and the diversion slope form a dredging system at the upper part of the side slope open cut tunnel together.
Preferably, the concrete protective body is laterally abutted against the high-pressure jet grouting reinforcement body.
Preferably, a foundation pit is excavated on the side slope, the open cut tunnel lining is arranged in the foundation pit, and backfill concrete is filled between the open cut tunnel lining and the side wall of the foundation pit close to the side slope below.
Preferably, an intersection point of a soil-rock interface between a first covering soil layer and the bedrock and the uppermost high-pressure jet grouting reinforcement body is taken as a junction point, a vertical surface passing through the junction point is taken as an interface, the interface is arranged along the length direction of the open cut tunnel structure, a part of the first covering soil layer located at the upstream of the interface is defined as a first covering soil layer, and a part of the first covering soil layer located at the downstream of the interface is defined as a second covering soil layer;
the side slope open cut tunnel supporting structure is designed according to the following steps:
A1. calculating the remaining sliding force of the first covering soil layer acting on the second covering soil layer by adopting a broken line sliding surface method;
A2. calculating the shearing resistance N of the high-pressure rotary spraying reinforcing body per linear meter along the line direction by using the reinforcing length of the high-pressure rotary spraying reinforcing body along the direction of the soil-rock interface, and calculating the resultant force F of the downward sliding force of the high-pressure rotary spraying reinforcing body along the line direction, wherein the downward sliding force of the upper covering soil layer and the upper covering soil layer along the direction of the soil-rock interface is borne by the high-pressure rotary spraying reinforcing body per linear meter along the line direction;
A3. obtaining a shearing resistance safety coefficient Ka of the high-pressure rotary-jetting reinforcement body based on the shearing resistance N of each linear meter of the high-pressure rotary-jetting reinforcement body and the resultant force F of each linear meter of the high-pressure rotary-jetting reinforcement body along the line direction, wherein the resultant force F of the downward sliding force of the upper covering soil layer part and the covering soil layer part along the direction of the soil-rock interface;
A4. whether the shear-resistant safety coefficient Ka of the high-pressure rotary-spraying reinforcement body meets Ka is more than or equal to K, if not, modifying the reinforcement length of the high-pressure rotary-spraying reinforcement body in the step A2 along the direction of the soil-rock interface, and repeating the steps A2-A4 until the shear-resistant safety coefficient Ka of the high-pressure rotary-spraying reinforcement body meets Ka is more than or equal to K, wherein K is the allowable shear-resistant safety coefficient of the high-pressure rotary-spraying reinforcement body;
A5. and when the shearing-resistant safety coefficient Ka of the high-pressure jet grouting reinforced body meets the condition that Ka is more than or equal to K, carrying out bearing capacity detection calculation on the bored pile.
Through the design method, the design of the high-pressure rotary spraying reinforcing body can be simply and effectively completed, and theoretical stress support is provided for the side slope open cut tunnel supporting structure.
Preferably, the shear-resistant safety coefficient Ka of the high-pressure jet grouting reinforced body in the step A3 is as follows:
Figure BDA0003737968740000041
in the formula: ka-high pressure jet grouting reinforcement body shear resistance safety factor, V-along the line direction each linear meter of one cover soil layer act on two cover soil layer on the remaining sliding force tangential component force, unit: kN/m; t-normal component force of remaining slip force acting on the second part of the cover layer every linear meter of the cover layer along the line direction, unit: kN/m; g-dead weight of two soil covering layers per linear meter along the line direction, unit: kN/m;
Figure BDA0003737968740000042
-angle between earth-rock interface and horizontal direction, τ -shear strength of high pressure jet grouting reinforcement, unit: kPa; l-high pressure jet grouting reinforcement body reinforces length, unit along the direction of the soil-rock interface: and m is selected.
The application also discloses a construction method for the side slope open cut tunnel supporting structure, which comprises the following steps:
s1, determining a position A of the open cut tunnel lining to be constructed;
s2, constructing a high-pressure rotary spraying reinforcement body in a side slope soil layer above the position A, and enabling the front end of the high-pressure rotary spraying reinforcement body to enter a bedrock;
s3, after the high-pressure jet grouting reinforcement body is solidified, constructing steel guide pipes on the top of the high-pressure jet grouting reinforcement body, arranging all the steel guide pipes along the length direction of the open cut tunnel lining, and performing grouting reinforcement after the steel guide pipes are inserted in place;
s4, excavating a soil body at the position A to the inverted arch bottom surface elevation of the open cut tunnel lining to form a foundation pit;
s5, constructing the cast-in-situ bored pile at the lower part of one end, far away from the upper side slope, of the open cut tunnel lining;
s6, pouring the open cut tunnel lining, and connecting the open cut tunnel lining with a cast-in-situ bored pile;
s7, pouring the concrete protection body, pouring a flow guide slope with the direction consistent with that of the slope on the upper portion of the concrete protection body, laying a reinforcing mesh on the surface layer of the concrete protection body, and firmly connecting the reinforcing mesh with the steel guide pipe;
and S8, backfilling concrete in the foundation pit.
According to the construction method for the side slope open cut tunnel supporting structure, the high-pressure jet grouting reinforcement body is constructed in the side slope soil layer above the position A, the front end of the high-pressure jet grouting reinforcement body enters the bedrock, the high-pressure jet grouting reinforcement body can play a role in pre-reinforcing the upper side slope, and the side slope is prevented from collapsing when a foundation pit is excavated and used for open cut tunnel lining;
after the high-pressure rotary spraying reinforcing body is solidified, constructing steel guide pipes at the top of the high-pressure rotary spraying reinforcing body, arranging all the steel guide pipes along the length direction of the open cut tunnel lining, inserting the steel guide pipes in place, and then performing grouting reinforcement, wherein the high-pressure rotary spraying reinforcing body can well support the steel guide pipes above the high-pressure rotary spraying reinforcing body, and meanwhile, the steel guide pipes are arranged on the high-pressure rotary spraying reinforcing body, so that the high-pressure rotary spraying reinforcing body can be well protected;
and constructing the cast-in-situ bored pile on the lower part of one end of the open cut tunnel lining, which is far away from the upper side slope, pouring the open cut tunnel lining, and connecting the open cut tunnel lining with the cast-in-situ bored pile. So that the cast-in-situ bored pile plays a role in supporting and fixing the open cut tunnel lining;
concrete protective bodies are poured above the open cut tunnel lining, so that the open cut tunnel lining can be protected;
the reinforcing mesh is laid on the surface layer of the concrete protective body, so that the concrete protective body can be reinforced, the concrete protective body is prevented from being damaged when a landslide and mud stone flow pass, the reinforcing mesh is firmly welded with the steel conduit, and the integrity of the structure can be enhanced; and ensure the smooth transition between the steel conduit and the guide slope; the top of the concrete protection body is provided with a guide slope along the slope direction, so that the concrete protection body can play a role in dredging landslide and debris flow, and can guide landslide and debris flow materials to be discharged from the steel guide pipe and the top of the open cut tunnel lining when disasters of shallow landslide and slope debris flow occur.
The open cut tunnel lining, the concrete protective body, the high-pressure rotary spraying reinforcing body and the cast-in-situ bored pile form an engineering whole fixed on the side slope bedrock together, when a shallow landslide and slope debris flow disaster occurs on a covering soil layer on the upper portion of a side slope, the sliding body and debris flow substances can be guided to be discharged from the upper portions of the high-pressure rotary spraying reinforcing body and the open cut tunnel lining, and the open cut tunnel structure is protected from the positive impact of the landslide and the debris flow.
According to the side slope open cut tunnel supporting structure constructed by the construction method, when disasters such as shallow landslide, slope debris flow and the like occur, safe operation of railway lines in open cut tunnel lining can be guaranteed, and the side slope open cut tunnel supporting structure is simple, economical and reasonable in construction and wide in application prospect.
Preferably, in step S1, the length of the section to be constructed as the open cut tunnel supporting structure is determined according to the development conditions of the landslide and the debris flow on the slope of the line and in combination with the line position.
Preferably, in step S2, the front end of the high-pressure jet grouting reinforced body enters the bedrock to be more than or equal to 0.5m.
Preferably, in the step S2, the steel guide pipes are arranged along a line, the distance between every two adjacent steel guide pipes is less than or equal to 20cm, the intersection angle of the axis of the steel guide pipe (1) and the horizontal line is 20-30 degrees, and the inserted bedrock is more than or equal to 2m.
Preferably, in step S4, the soil body at the excavation position a reaches the elevation of the bottom surface of the open cut tunnel lining inverted arch, and the part of the high-pressure jet grouting reinforcement body at the excavation surface position is correspondingly cut in the excavation process, so as to finally form the foundation pit.
The high-pressure rotary spraying reinforcing body is moderate in strength, easy to break and cut and free of influence on excavation construction of the foundation pit, and construction of open cut tunnel lining of excavation construction of the foundation pit is more convenient.
In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:
1. according to the side slope open cut tunnel supporting structure, the high-pressure jet grouting reinforcement body is arranged in the side slope soil layer above the open cut tunnel lining, so that the upper side slope can be pre-reinforced, and the side slope is prevented from collapsing when the excavation foundation pit is used for lining the open cut tunnel; meanwhile, the high-pressure rotary spraying reinforcing body is moderate in strength and can be broken by an excavator, and excavation construction of the foundation pit is not influenced, so that open cut tunnel lining construction in excavation construction of the foundation pit is more convenient. Concrete protective bodies are poured above the open cut tunnel lining, and the open cut tunnel lining can be protected. The top of the concrete protection body is provided with a guide slope along the slope direction, so that the concrete protection body can play a role in dredging landslide and debris flow, and can guide landslide and debris flow substances to be discharged from the upper side of the open cut tunnel lining when disasters of shallow landslide and slope debris flow occur. The lower part of one end, far away from the upper side slope, of the open cut tunnel lining is connected with a bored pile for supporting the open cut tunnel lining, the open cut tunnel lining can be supported and fixed, the open cut tunnel lining, the concrete protective body, the high-pressure rotary jet reinforcing body and the bored pile jointly form an engineering whole fixed on the side slope bedrock, when a shallow landslide and a slope debris flow disaster happen to a soil covering layer on the upper portion of a side slope, landslide and debris flow substances can be guided to be discharged from the high-pressure rotary jet reinforcing body and the upper part of the open cut tunnel lining, the open cut tunnel structure is protected from the landslide and the front impact of the debris flow, the structure can guarantee the safe operation of railway lines in the open cut tunnel lining when the shallow landslide, the slope debris flow and other disasters happen, and the construction is simple, economic and reasonable, and the application prospect is wide.
2. According to the construction method for the side slope open cut tunnel supporting structure, the high-pressure jet grouting reinforcement body is constructed in the side slope soil layer above the position A, the front end of the high-pressure jet grouting reinforcement body enters the bedrock, the high-pressure jet grouting reinforcement body can play a pre-reinforcement role on the upper side slope, and the side slope is prevented from collapsing when the excavated foundation pit is used for constructing the open cut tunnel lining; after the high-pressure rotary spraying reinforcing body is solidified, constructing steel guide pipes at the top of the high-pressure rotary spraying reinforcing body, arranging all the steel guide pipes along the length direction of the open cut tunnel lining, inserting the steel guide pipes in place, and then performing grouting reinforcement, wherein the high-pressure rotary spraying reinforcing body can well support the steel guide pipes above the high-pressure rotary spraying reinforcing body, and meanwhile, the steel guide pipes are arranged on the high-pressure rotary spraying reinforcing body, so that the high-pressure rotary spraying reinforcing body can be well protected; and constructing the cast-in-situ bored pile at the lower part of one end of the open cut tunnel lining, which is far away from the upper side slope, then pouring the open cut tunnel lining, and connecting the open cut tunnel lining with the cast-in-situ bored pile. So that the cast-in-situ bored pile plays a role in supporting and fixing the open cut tunnel lining; concrete protective bodies are poured above the open cut tunnel lining, so that the open cut tunnel lining can be protected; the reinforcing mesh is laid on the surface layer of the concrete protective body, so that the reinforcing mesh can reinforce the concrete protective body, the concrete protective body is prevented from being damaged when the concrete protective body slides on a slope and mud stone flows, the reinforcing mesh is firmly welded with the steel guide pipe, and the integrity of the structure can be enhanced; and ensure the smooth transition between the steel conduit and the guide slope; the top of the concrete protection body is provided with a guide slope along the slope direction, so that the concrete protection body can play a role in dredging landslide and debris flow, and can guide landslide and debris flow materials to be discharged from the steel guide pipe and the top of the open cut tunnel lining when disasters of shallow landslide and slope debris flow occur. The open cut tunnel lining, the concrete protective body, the high-pressure rotary spraying reinforcing body and the bored pile jointly form an engineering whole body fixed on the foundation rock of the side slope, and when shallow landslide and slope debris flow disasters occur on the upper covering soil layer of the side slope, the sliding body and debris flow substances can be guided to be discharged from the high-pressure rotary spraying reinforcing body and the open cut tunnel lining, so that the open cut tunnel structure is protected from the positive impact of the landslide and the debris flow. According to the side slope open cut tunnel supporting structure constructed by the construction method, when disasters such as shallow landslide, slope debris flow and the like occur, safe operation of railway lines in open cut tunnel lining can be guaranteed, and the side slope open cut tunnel supporting structure is simple, economical and reasonable in construction and wide in application prospect.
Drawings
Fig. 1 is a schematic structural view of a side slope open cut tunnel supporting structure of the present invention.
FIG. 2 is a schematic diagram illustrating a step of applying a high-pressure jet grouting reinforcement body in a construction method for a side slope open cut tunnel supporting structure according to the present invention;
fig. 3 is a schematic diagram illustrating a step of constructing a cast-in-situ bored pile according to the present invention in a construction method for a side slope open cut tunnel supporting structure;
fig. 4 is a schematic diagram illustrating steps of constructing open cut tunnel lining in a construction method for a side slope open cut tunnel supporting structure according to the present invention;
fig. 5 is a design schematic diagram of a side slope open cut tunnel supporting structure of the invention.
An icon: 1-a steel conduit; 10-bedrock; 11-upper side slope; 12-foundation pit; 13-lower side slope; 14-high pressure jet grouting pile machine; 15, a rotary drilling rig; 2-high pressure rotary spraying to strengthen the body; 3-drilling a cast-in-place pile; 4-open cut tunnel lining; 5-concrete protection; 6-reinforcing mesh; 7-guiding slope; 8-backfilling concrete; 9-covering a soil layer; 91-covering a soil layer part; 92-covering soil layer two; 93-earth-rock interface; 94-interface.
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
As shown in fig. 1 to 4, the open cut tunnel supporting structure for side slopes in this embodiment includes a open cut tunnel lining 4 disposed on a side slope, a high-pressure jet grouting reinforcement body 2 is disposed in a soil layer of a side slope 11 above the open cut tunnel lining 4, a concrete protection body 5 is disposed above a top of the open cut tunnel lining 4, the open cut tunnel lining 4 is far away from a lower portion of one end of the upper side slope 11 and is connected with a bored pile 3 for supporting the open cut tunnel lining 4, a diversion slope 7 along the side slope direction is disposed at the top of the concrete protection body 5, the soil layer below the upper side slope 11 includes a first cover soil layer 9 and a bedrock 10 located below the first cover soil layer 9, and one end of the high-pressure jet grouting reinforcement body 2 passes through the first cover soil layer 9 and extends into the bedrock 10.
In the open cut tunnel supporting structure for the side slope according to the embodiment, a high-pressure jet grouting reinforcement body 2 is arranged in a soil layer of an upper side slope 11 of an open cut tunnel lining 4, one end of the high-pressure jet grouting reinforcement body 2 penetrates through a first covering soil layer 9 and extends into a bedrock 10, so that a pre-reinforcement effect can be achieved on the upper side slope 11, and the side slope is prevented from collapsing when a foundation pit 12 is excavated and used as the open cut tunnel lining 4; meanwhile, the high-pressure jet grouting reinforcement body 2 is moderate in strength and can be broken by an excavator, excavation construction of the foundation pit 12 is not affected, and the excavation construction of the foundation pit 12 for the open cut tunnel lining 4 is more convenient. Concrete protective bodies 5 are poured above the open cut tunnel linings 4, and the open cut tunnel linings 4 can be protected. The top of the concrete protection body 5 is provided with a guide slope 7 along the side slope direction, which can play a role in dredging landslide and debris flow, and can guide landslide and debris flow substances to be discharged from the upper side of the open cut tunnel lining 4 when disasters of shallow landslide and slope debris flow occur. The lower part of one end of the open cut tunnel lining 4, which is far away from the upper side slope 11, is connected with a cast-in-situ bored pile 3 for supporting the open cut tunnel lining 4, so that the open cut tunnel lining 4 can be supported and fixed.
The open cut tunnel lining 4, the concrete protective body 5, the high-pressure rotary spraying reinforcing body 2 and the cast-in-situ bored pile 3 form an engineering whole fixed on the side slope bedrock together, when a shallow landslide and slope debris flow disaster occurs on a covering soil layer on the upper portion of a side slope, the sliding body and debris flow substances can be guided to be discharged from the upper portion of the high-pressure rotary spraying reinforcing body 2 and the open cut tunnel lining 4, and the open cut tunnel structure is protected from the front impact of the landslide and the debris flow.
The structure can ensure the safe operation of railway lines in the open cut tunnel lining 4 when disasters such as shallow landslide, slope debris flow and the like occur, and has the advantages of simple construction, economy, reasonability and wide application prospect.
On the basis of the above, it is further preferable that one end of the high-pressure jet-grouting reinforcement body 2 passes through the overburden 9 and extends into the bedrock 10.
On the basis, in a further preferable mode, a steel guide pipe 1 is further arranged in a soil layer of the upper side slope 11, one end of the steel guide pipe 1 penetrates through a first soil covering layer 9 and extends into a bedrock 10, all the steel guide pipes 1 are arranged along the length direction of the open cut tunnel lining 4, the steel guide pipe 1 is located above the high-pressure rotary spraying reinforcement body 2, a reinforcing mesh 6 is laid on the upper surface of the concrete protection body 5, and the reinforcing mesh 6 is connected with the steel guide pipe 1.
The diversion slope 7 and the upper slope 11 form a continuous slope, and the steel guide pipe 1, the high-pressure jet grouting reinforcement body 2, the open cut tunnel lining 4, the concrete protection body 5, the reinforcing mesh 6 and the diversion slope 7 form a dredging system at the upper part of the open cut tunnel of the slope together.
In the slope open cut tunnel supporting structure of the embodiment, the steel conduit 1 is located above the high-pressure jet grouting reinforcement body 2, the high-pressure jet grouting reinforcement body 2 can play a good supporting role for the steel conduit 1 above, and meanwhile, the steel conduit 1 is arranged above the high-pressure jet grouting reinforcement body 2 and can play a good protection role for the high-pressure jet grouting reinforcement body 2. The reinforcing mesh 6 is laid on the surface layer of the concrete protection body 5, so that the concrete protection body 5 can be reinforced, the concrete protection body 5 is prevented from being damaged when landslide and mud stone flow pass, the reinforcing mesh 6 and the steel conduit 1 are firmly welded, and the integrity of the structure can be enhanced; and ensure the smooth transition between the steel guide pipe 1 and the guide slope 7; the top of the concrete protection body 5 is provided with a guide slope 7 along the slope direction, which can play a role in dredging landslide and debris flow, and can guide the landslide and debris flow substances to be discharged from the upper side of the steel guide pipe 1 and the open cut tunnel lining 4 when a disaster of shallow landslide and slope debris flow occurs.
On the basis of the above, in a further preferred manner, the concrete protection body 5 abuts against the high-pressure jet grouting reinforcement body 2 from the side.
On the basis, in a further preferable mode, a foundation pit 12 is excavated on the side slope, the open cut tunnel lining 4 is arranged in the foundation pit 12, and backfill concrete 8 is filled between the open cut tunnel lining 4 and the side wall, close to the side slope 13 below, of the foundation pit 12.
Taking landslide and debris flow areas as examples, specifically, referring to fig. 1, the high and steep slope open cut tunnel supporting structure described in this embodiment is used for supporting an open cut tunnel structure, and comprises an open cut tunnel lining 4, a steel conduit 1 arranged above the open cut tunnel lining 4, a high-pressure jet grouting reinforcement body 2, a concrete protection body 5 and other guiding and protecting structures; and the cast-in-situ bored pile 3 arranged below the open cut tunnel lining 4 supports a fixed structure. Firstly, excavating a mechanical construction platform, and pre-reinforcing a cover soil layer 9 above a open cut tunnel lining 4 obliquely by adopting a mechanical high-pressure jet grouting method to form a high-pressure jet grouting reinforced body 2, wherein steel guide pipes 1 are arranged at the top of the reinforced body 2 side by side along the line direction, grouting holes are arranged at the periphery and the end part close to the steel guide pipes 1, the steel guide pipes 1 are inserted into a foundation rock 10 and are subjected to grouting reinforcement, the open cut tunnel lining 4 is fixed on the foundation rock 10 through drilling grouting piles 3, a concrete protective body 5 is poured above the open cut tunnel lining 4, a diversion slope 7 along the slope direction is arranged at the top of the concrete protective body 5, a reinforcing mesh 6 is laid on the surface of the concrete protective body 5 for reinforcement, and the reinforcing mesh 6 and the steel guide pipes 1 are welded firmly. The structure can guarantee the safe operation of railway lines when disasters such as shallow landslide, slope debris flow and the like occur, and has the advantages of simple construction, economy, reasonability and wide application prospect.
Example 2
As shown in fig. 5, the slope open cut tunnel supporting structure described in embodiment 1 can be designed by the design method described in this embodiment, and the design calculation steps are as follows:
A1. calculating the remaining sliding force of the first covering soil layer 91 acting on the second covering soil layer 92 by adopting a broken line sliding surface method;
A2. calculating the shearing resistance N of the high-pressure rotary spraying reinforcing body 2 per linear meter along the line direction by using the reinforcing length of the high-pressure rotary spraying reinforcing body 2 along the direction of the soil-rock interface 93, and calculating the resultant force F of the downward sliding force of the high-pressure rotary spraying reinforcing body 2 per linear meter along the line direction along the direction of the soil-rock interface 93, wherein the resultant force F of the downward sliding force of the first part 91 of the upper covering soil layer and the second part 92 of the covering soil layer along the direction of the soil-rock interface 93 is born by the high-pressure rotary spraying reinforcing body 2 per linear meter along the line direction;
A3. obtaining the shearing resistance safety coefficient Ka of the high-pressure rotary-jetting reinforcement body 2 based on the shearing resistance N of the high-pressure rotary-jetting reinforcement body 2 per linear meter and the resultant force F of the downward sliding force of the upper covering soil layer part 91 and the covering soil layer part 92 along the direction of the soil-rock interface 93 borne by the high-pressure rotary-jetting reinforcement body 2 per linear meter along the line direction;
A4. whether the shear-resistant safety coefficient Ka of the high-pressure rotary spraying reinforcement body 2 meets Ka is more than or equal to K, if not, modifying the reinforcement length of the high-pressure rotary spraying reinforcement body 2 along the direction of the soil-rock interface 93 in the step A2, and repeating the steps A2-A4 until the shear-resistant safety coefficient Ka of the high-pressure rotary spraying reinforcement body 2 meets Ka is more than or equal to K, wherein K is the allowable shear-resistant safety coefficient of the high-pressure rotary spraying reinforcement body 2;
A5. and when the shearing-resistant safety coefficient Ka of the high-pressure jet grouting reinforced body 2 meets the condition that Ka is more than or equal to K, carrying out bearing capacity calculation on the cast-in-situ bored pile 3.
Through the design method, the design of the high-pressure rotary spraying reinforcing body 2 can be simply and effectively completed, and theoretical stress support is provided for the side slope open cut tunnel supporting structure.
Specifically, the shear-resistant safety coefficient Ka of the high-pressure jet grouting reinforced body 2 in the step A3 is as follows:
Figure BDA0003737968740000121
in the formula: ka-high pressure jet grouting reinforcement body 2 shear resistance factor of safety, V-the remaining slip force tangential component force, unit, acting on the second portion 92 of the overburden layer every linear meter of the first portion 91 of the overburden layer along the line direction: kN/m; t-remaining normal component of slip force acting on the second part 92 of the overburden layer 91 per linear meter of the overburden layer 91 along the line direction, unit: kN/m; g-the dead weight of the second part 92 of the soil covering layer of each linear meter along the line direction, unit: kN/m;
Figure BDA0003737968740000122
angle of earth-rock interface 93 to horizontal, τ -shear strength of high pressure jet reinforced body 2, unit: kPa; l-high pressure jet grouting reinforcement body 2 reinforces length, unit along the direction of the soil-rock interface 93: and m is selected.
A detailed preferred mode:
1. high-pressure rotary spraying reinforced body shear strength checking calculation method
Suppose that: the thrust of the soil covering layer above the open cut tunnel structure is completely borne by the high-pressure jet grouting reinforcement body, and the structural strength of the open cut tunnel structure is taken as a safety margin. The intersection point of the soil-rock interface 93 between the first overburden 9 and the bedrock 10 and the uppermost high-pressure jet grouting reinforcement body 2 is taken as a junction point, a vertical surface passing through the junction point is taken as an interface 94, the interface 94 is arranged along the length direction of the open cut tunnel structure, the part of the first overburden 9 located at the upstream of the interface 94 is defined as a first overburden part 91, and the part of the first overburden 9 located at the downstream of the interface 94 is defined as a second overburden part 92.
Calculating the remaining sliding force of the first covering soil layer 91 acting on the second covering soil layer 92 by adopting a broken line sliding surface method;
calculating the resultant force F of the sliding force of the upper covering soil layer part 91 and the covering soil layer part 92 along the direction of the soil-rock interface 93 born by the high-pressure rotary spraying reinforcement body 2 along the line direction every linear meter:
Figure BDA0003737968740000131
in the formula: f is the resultant force of the gliding force of each linear meter of the first part 91 of the soil covering layer and the second part 92 of the soil covering layer along the direction of the soil-rock interface 93, unit: kN/m; v-remaining tangential component of slip force per linear meter of one part 91 of the overburden layer acting on the second part 92 of the overburden layer along the line direction, unit: kN/m; t-remaining normal component of slip force acting on the second part 92 of the overburden layer 91 per linear meter of the overburden layer 91 along the line direction, unit: kN/m; g-the dead weight of the second part 92 of the soil covering layer per linear meter along the line direction, unit: kN/m;
Figure BDA0003737968740000132
the angle of the earth-rock interface 93 to the horizontal.
3, high-pressure rotary spraying reinforcing body 2 in every linear meter along the line direction, wherein the shear force N is as follows:
N=τL
in the formula: n-along the line direction every linear meter high pressure jet grouting reinforcement body 2 shear resistance, unit: kN/m; τ — shear strength of high pressure jet grouting reinforcement 2, unit: kPa; l-high pressure jet grouting reinforcement body 2 reinforces length, unit along the direction of the soil-rock interface 93: and m is selected.
Figure BDA0003737968740000133
In the formula: the Ka-high pressure jet grouting reinforcement body 2 shear-resistant safety coefficient should not be less than 1.5;
[K] the shearing-resistant safety factor is 1.5 for the high-pressure rotary spraying reinforcing body 2.
3. Detection and calculation of bearing capacity of cast-in-situ bored pile 3
The rock-entering depth of the cast-in-situ bored pile 3 is not less than 2m, and the pile foundation bearing capacity of the cast-in-situ bored pile 3 is detected according to the most adverse condition, namely the pile foundation bears the dead weight of the 1/2 open cut tunnel structure.
The vertical bearing capacity calculation of the 3 pile foundations of the bored pile meets the following requirements:
N k ≤R
N k =N h d
N h =N 1 +N 2 +N 3 +N 4
in the formula, N k Under the standard combined action of load effect, the vertical force born by the pile foundation of the single cast-in-situ bored pile 3 is expressed in the unit: kN; n is a radical of hydrogen h Under the standard combination action of load effect, the dead weight of the open cut tunnel structure per linear meter along the line direction is as follows: kN/m; d-the spacing of bored pile 3 along the line direction, unit: m; r-3 vertical bearing capacity characteristic value, unit of single bored pile: kN;
N 1 -lining of open cut tunnel of every linear meter along the line direction line with a self weight of 4, unit: kN/m; n is a radical of hydrogen 2 -the weight per linear meter of the concrete protection body 5 along the line direction, unit: kN/m; n is a radical of 3 -the weight per linear meter of reinforcing mat 6 along the line direction, unit: kN/m; n is a radical of hydrogen 4 -guiding slope 7 dead weight per linear meter along the line direction, unit: kN/m;
R=Q uk /K
in the formula Q uk -vertical ultimate standard value of bearing capacity, unit, for a single bored pile 3: kN can be calculated according to the technical specification of the building pile foundation by combining geological conditions. K is a safety coefficient, and K =2 is taken.
Example 3
As shown in fig. 2 to 4, a construction method for a side slope open cut tunnel support structure according to embodiment 1 or 2 includes the following steps:
s1, determining a position A of the open cut tunnel lining 4 to be constructed;
s2, constructing a high-pressure rotary spraying reinforcement body 2 in a soil layer of the side slope 11 above the position A, and enabling the front end of the high-pressure rotary spraying reinforcement body 2 to enter a bedrock 10;
s3, after the high-pressure jet grouting reinforcement body 2 is solidified, constructing steel guide pipes 1 at the top of the high-pressure jet grouting reinforcement body 2, arranging all the steel guide pipes 1 along the length direction of the open cut tunnel lining 4, and performing grouting reinforcement after the steel guide pipes 1 are inserted in place;
s4, excavating soil at the position A to the elevation of the bottom surface of the inverted arch of the open cut tunnel lining 4 to form a foundation pit 12;
s5, constructing the cast-in-situ bored pile 3 at the lower part of one end, far away from the upper side slope 11, of the open cut tunnel lining 4;
and S6, pouring the open cut tunnel lining 4, and connecting the open cut tunnel lining 4 with the cast-in-situ bored pile 3.
And S7, pouring the concrete protection body 5, pouring a flow guide slope 7 with the direction consistent with that of the slope on the upper portion of the concrete protection body 5, paving a reinforcing mesh 6 on the surface layer of the concrete protection body 5, and firmly connecting the reinforcing mesh 6 with the steel guide pipe 1.
And S8, backfilling concrete in the foundation pit 12.
In the open cut tunnel supporting structure for the side slope, according to the embodiment, the high-pressure jet grouting reinforcement body 2 is constructed in the soil layer of the upper side slope 11 at the position A, the front end of the high-pressure jet grouting reinforcement body 2 enters the bedrock 10, and the high-pressure jet grouting reinforcement body 2 can pre-reinforce the upper side slope 11 and prevent the side slope from collapsing when the excavation foundation pit 12 is constructed to serve as the open cut tunnel lining 4;
after the high-pressure jet grouting reinforcement body 2 is solidified, constructing steel guide pipes 1 at the top of the high-pressure jet grouting reinforcement body 2, arranging all the steel guide pipes 1 along the length direction of the open cut tunnel lining 4, inserting the steel guide pipes 1 in place, and then performing grouting reinforcement, wherein the high-pressure jet grouting reinforcement body 2 can well support the steel guide pipes 1 above, and meanwhile, the steel guide pipes 1 are arranged on the high-pressure jet grouting reinforcement body 2 and can well protect the high-pressure jet grouting reinforcement body 2;
and constructing the cast-in-situ bored pile 3 on the lower part of one end of the open cut tunnel lining 4 far away from the upper side slope 11, then casting the open cut tunnel lining 4, and connecting the open cut tunnel lining 4 with the cast-in-situ bored pile 3. So that the cast-in-situ bored pile 3 plays a role in supporting and fixing the open cut tunnel lining 4;
a concrete protective body 5 is poured above the open cut tunnel lining 4, so that the open cut tunnel lining 4 can be protected;
the reinforcing mesh 6 is laid on the surface layer of the concrete protection body 5, so that the concrete protection body 5 can be reinforced, the concrete protection body 5 is prevented from being damaged when landslide and mud stone flow pass, the reinforcing mesh 6 and the steel conduit 1 are firmly welded, and the integrity of the structure can be enhanced; and ensure the smooth transition between the steel guide pipe 1 and the guide slope 7; the top of the concrete protection body 5 is provided with a guide slope 7 along the slope direction, which can play a role in dredging landslide and debris flow, and can guide the landslide and debris flow substances to be discharged from the upper side of the steel guide pipe 1 and the open cut tunnel lining 4 when a disaster of shallow landslide and slope debris flow occurs.
The open cut tunnel lining 4, the concrete protective body 5, the high-pressure rotary jet reinforced body 2 and the bored pile 3 jointly form an engineering whole body fixed on a side slope bed rock, and when shallow landslide and slope debris flow disasters occur on a covering soil layer on the upper portion of a side slope, the sliding bodies and debris flow substances can be guided to be discharged from the upper portion of the high-pressure rotary jet reinforced body 2 and the open cut tunnel lining 4, so that the open cut tunnel structure is protected from the front impact of the landslide and the debris flow.
According to the side slope open cut tunnel supporting structure constructed by the construction method, when disasters such as shallow landslide and slope debris flow occur, safe operation of railway lines in the open cut tunnel lining 4 can be guaranteed, and the side slope open cut tunnel supporting structure is simple, economical and reasonable in construction and wide in application prospect.
On the basis, in a further preferable mode, in step S1, the length of the section to be constructed as the open cut tunnel supporting structure is determined according to the development conditions of the landslide and the debris flow on the slope of the line and by combining the line position.
In addition to the above, in a further preferable mode, in step S2, the front end of the high-pressure jet grouting reinforcement body 2 enters the bedrock by 10 m or more and 0.5m or more.
On the basis, in a further preferable mode, in the step S2, the steel guide pipes 1 are arranged along a line, the distance between the adjacent steel guide pipes 1 is less than or equal to 20cm, the intersection angle of the axis of the steel guide pipe (1) and the horizontal line is 20-30 degrees, and the inserted bedrock is more than or equal to 2m.
On the basis, in a further preferable mode, in step S4, the soil body at the excavation position a is cut to the elevation of the bottom surface of the inverted arch of the open cut tunnel lining 4, and the part of the high-pressure jet grouting reinforcement body 2 located at the excavation surface position is correspondingly cut in the excavation process, so as to finally form the foundation pit 12.
The high-pressure jet grouting reinforcement body 2 is moderate in strength, easy to break and cut and free of influence on excavation construction of the foundation pit 12, and construction of the open cut tunnel lining 4 in excavation of the foundation pit 12 is more convenient.
Specifically, landslide and debris flow areas are taken as examples; the construction method of the open cut tunnel supporting structure of the high and steep slope is used for supporting the open cut tunnel structure and comprises the following steps:
1. determining the length of a section needing to be constructed into a open cut tunnel supporting structure according to the development conditions of the mud-rock flow of the shallow landslide and the slope of the line and the combination of line positions;
2. the high-pressure rotary jet grouting pile machine 14 is utilized to form a high-pressure rotary jet grouting reinforcement body 2 formed by mutually engaging cement-soil columns through repeated reciprocating drilling, jetting, rotating and lifting operations, the reinforcement body is required to enter a bedrock by 10 m or more than 0.5m, and the main parameter index requirements of the reinforcement body are shown in the following table;
modulus of compression Cohesion force Internal angle of friction Compressive strength of single axis
500MPa 0.3MPa 35° 5MPa
3. After the high-pressure rotary spraying reinforcement body 2 is solidified, constructing steel guide pipes 1 on the top of the high-pressure rotary spraying reinforcement body 2, arranging the steel guide pipes 1 side by side along a line, wherein the distance between every two adjacent guide pipes is less than or equal to 20cm, the intersection angle of the steel guide pipes 1 and a horizontal line is preferably 20-30 degrees, the inserted bedrock is 10 or more than or equal to 2m, and grouting reinforcement is carried out after the steel guide pipes 1 are inserted in place;
4. excavating the soil body of the side slope to the elevation of the bottom surface of the inverted arch, carrying out necessary cutting on the high-pressure jet grouting reinforcement body 2 at the position of an excavation surface in the excavation process, and excavating section by section during excavation;
5. adopting a rotary drilling rig 15 to construct a cast-in-situ bored pile 3, chiseling pile head concrete after the cast-in-situ bored pile 3 is cast, and reserving pile top reinforcing steel bars with the length of more than or equal to 0.5m;
6. and (3) pouring the open cut tunnel lining 4 by using the trolley, and when binding the open cut tunnel lining 4 reinforcing steel bars, firmly binding the open cut tunnel lining 4 reinforcing steel bars with the pile top reinforcing steel bars of the cast-in-situ bored pile 3.
7. And pouring a concrete protection body 5 of the open cut tunnel lining 4, pouring a diversion slope 7 with the same direction as the slope on the upper part of the concrete protection body 5, paving a reinforcing mesh 6 on the surface layer of the concrete protection body 5, and firmly welding the reinforcing mesh 6 and the steel guide pipe 1.
8. And backfilling the foundation pit 12 with concrete.
The construction method has the following beneficial effects:
the high-pressure jet grouting reinforcement body 2 is applied in advance, so that the side slope can be pre-reinforced, and the side slope is prevented from slipping when the open cut tunnel lining 4 is excavated and applied;
the high-pressure rotary spraying reinforcing body 2 is moderate in strength, can be broken by an excavator, and is convenient to excavate and construct;
the high-pressure rotary spraying reinforcing body 2 can play a good role in supporting the steel guide pipe 1 above;
the steel conduit 1 is arranged on the high-pressure jet grouting reinforcement body 2, and can well protect the reinforcement body;
the concrete protection body 5 is poured above the open cut tunnel lining 4, the open cut tunnel lining 4 can be protected, the reinforcing mesh 6 is paved on the surface layer of the concrete protection body 5, the concrete protection body 5 can be reinforced, the concrete protection body 5 is prevented from being damaged when landslide and mud stone flow pass, the reinforcing mesh 6 is firmly welded with the steel conduit 1, and the integrity of the structure can be enhanced; and ensure the smooth transition between the steel guide pipe 1 and the guide slope 7;
the inclined diversion slope 7 is arranged on the concrete protection body 5, so that the concrete protection body can play a role in dredging landslide and debris flow, and can guide landslide and debris flow substances to be discharged from the upper part of the steel guide pipe 1 and the open cut tunnel structure when a shallow landslide and slope debris flow disaster occurs;
and a cast-in-situ bored pile 3 is arranged below the open cut tunnel lining 4 and can support and fix the open cut tunnel lining 4.
The open cut tunnel lining 4, the concrete protective body 5, the high-pressure rotary jet grouting reinforcing body 2 and the bored pile 3 jointly form an engineering whole fixed on a side slope bed rock 10, and when shallow landslide and slope debris flow disasters occur on a covering soil layer 9 on the upper portion of a side slope, the sliding bodies and debris flow materials can be guided to be discharged from the upper portion of the steel guide pipe 1 and the open cut tunnel structure, so that the open cut tunnel structure is protected from the front impact of landslide and debris flow.
The structure can guarantee the safe operation of railway lines when disasters such as shallow landslide, slope debris flow and the like occur, and has the advantages of simple construction, economy, reasonability and wide application prospect.
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 (10)

1. The utility model provides a side slope open cut tunnel supporting construction, its characterized in that, is including setting up open cut tunnel lining (4) on the side slope, be provided with high pressure jet grouting reinforcement body (2) in the soil layer of open cut tunnel lining (4) top side slope (11), open cut tunnel lining (4) top is provided with concrete protection body (5), open cut tunnel lining (4) are kept away from the sub-unit connection of top side slope (11) one end has and is used for supporting drilling bored concrete pile (3) of open cut tunnel lining (4), concrete protection body (5) top is provided with water conservancy diversion slope (7) along the side slope direction, the soil layer under top side slope (11) includes first overburden layer (9) and is located bedrock (10) of first overburden layer (9) lower part, the one end of high pressure jet grouting reinforcement body (2) is passed first overburden layer (9) and is stretched into in bedrock (10).
2. The side slope open cut tunnel supporting structure according to claim 1, wherein a steel guide pipe (1) is further arranged in the soil layer of the upper side slope (11), one end of the steel guide pipe (1) penetrates through a first soil covering layer (9) and extends into a bedrock (10), all the steel guide pipes (1) are arranged along the length direction of the open cut tunnel lining (4), the steel guide pipe (1) is located above the high-pressure jet grouting reinforcement body (2), a reinforcing mesh (6) is paved and connected on the upper surface of the concrete protection body (5), and the reinforcing mesh (6) is connected with the steel guide pipes (1).
3. The side slope open cut tunnel supporting structure according to claim 2, wherein the guide slope (7) and the upper slope (11) form a continuous side slope, and the steel guide pipe (1), the high-pressure jet grouting reinforcement body (2), the open cut tunnel lining (4), the concrete protection body (5), the reinforcing mesh (6) and the guide slope (7) jointly form a dredging system at the upper part of the side slope open cut tunnel.
4. A side slope open cut tunnel supporting structure according to claim 1, characterized in that the concrete protection body (5) is laterally abutted against the high pressure jet grouting reinforcement body (2).
5. The side slope open cut tunnel supporting structure according to claim 1, wherein a foundation pit (12) is dug on the side slope, the open cut tunnel lining (4) is arranged in the foundation pit (12), and backfill concrete (8) is filled between the open cut tunnel lining (4) and the side wall of the foundation pit (12) close to the side slope (13) below.
6. A side slope open cut tunnel supporting structure according to claim 2, wherein an intersection point of a soil-rock interface (93) between a first cover layer (9) and said bedrock (10) and said uppermost high-pressure jet grouting reinforcement body (2) is an intersection point, a vertical plane passing through said intersection point is an interface (94), said interface (94) is disposed along a length direction of the open cut tunnel structure, and a portion of said first cover layer (9) located upstream of said interface (94) is defined as a first cover layer portion (91), and a portion of said first cover layer (9) located downstream of said interface (94) is defined as a second cover layer portion (92);
the side slope open cut tunnel supporting structure is designed according to the following steps:
A1. calculating the residual sliding force of the first covering soil layer (91) acting on the second covering soil layer (92) by adopting a broken line sliding surface method;
A2. the shear resistance N of the high-pressure rotary spraying reinforcing body (2) per linear meter along the line direction is calculated by using the reinforcing length of the high-pressure rotary spraying reinforcing body (2) along the direction of the soil-rock interface (93), and the resultant force F of the downward sliding force of the upper soil covering layer part (91) and the soil covering layer part (92) along the direction of the soil-rock interface (93) borne by the high-pressure rotary spraying reinforcing body (2) per linear meter along the line direction is calculated by using the residual downward sliding force acted on the soil covering layer part II (92) by the soil covering layer part I (91);
A3. obtaining the shearing resistance safety coefficient Ka of the high-pressure rotary spraying reinforcement body (2) based on the shearing resistance N of the high-pressure rotary spraying reinforcement body (2) per linear meter and the resultant force F of the gliding force of the first part (91) of the upper covering layer and the second part (92) of the covering layer along the direction of the soil-rock interface (93) born by the high-pressure rotary spraying reinforcement body (2) per linear meter along the line direction;
A4. whether the shear-resistant safety coefficient Ka of the high-pressure rotary-spraying reinforcing body (2) meets Ka ≧ K or not is judged, if not, the reinforcing length of the high-pressure rotary-spraying reinforcing body (2) along the direction of the soil-rock interface (93) in the step A2 is modified, the steps A2-A4 are repeated until the shear-resistant safety coefficient Ka of the high-pressure rotary-spraying reinforcing body (2) meets Ka ≧ K, wherein [ K ] is the shear-resistant safety coefficient allowed by the high-pressure rotary-spraying reinforcing body (2);
A5. and when the shearing-resistant safety coefficient Ka of the high-pressure jet grouting reinforced body (2) meets the condition that Ka is more than or equal to K, carrying out bearing capacity calculation on the cast-in-situ bored pile (3).
7. The side slope open cut tunnel supporting structure according to claim 6, wherein the shear-resistant safety coefficient Ka of the high-pressure jet grouting reinforcement body (2) in the step A3 is specifically as follows:
Figure FDA0003737968730000031
in the formula: ka-high pressure jet grouting reinforcement body (2) safety coefficient that shears, V-along the direction of the line one (91) of each linear meter of overburden layer act on two (92) of overburden layer the remaining glide force tangential component, unit: kN/m; t-the remaining normal component of the slip force acting on the second part of the overburden (92) per linear meter of the first part of the overburden (91) along the line direction, unit: kN/m; g-dead weight of two parts (92) of each linear meter of the soil covering layer along the line direction, unit: kN/m;
Figure FDA0003737968730000032
-angle of earth-rock interface (93) to horizontal,. Tau. -shear strength of high pressure jet reinforced body (2), unit: kPa; l-high pressure jet grouting reinforcement body (2) reinforces length, unit along soil-rock interface (93) direction: and m is selected.
8. A construction method for the side slope open cut tunnel support structure according to any one of claims 1 to 7, characterized by comprising the steps of:
s1, determining a position A of the open cut tunnel lining (4) to be constructed;
s2, constructing a high-pressure rotary spraying reinforcement body (2) in a soil layer of the side slope (11) above the position A, and enabling the front end of the high-pressure rotary spraying reinforcement body (2) to enter a bedrock (10);
s3, after the high-pressure jet grouting reinforcement body (2) is solidified, constructing steel guide pipes (1) at the top of the high-pressure jet grouting reinforcement body (2), arranging all the steel guide pipes (1) along the length direction of the open cut tunnel lining (4), and performing grouting reinforcement after the steel guide pipes (1) are inserted in place;
s4, excavating soil at the position A to the inverted arch bottom surface elevation of the open cut tunnel lining (4) to form a foundation pit (12);
s5, constructing the cast-in-situ bored pile (3) at the lower part of one end, far away from the upper side slope (11), of the open cut tunnel lining (4);
s6, pouring the open cut tunnel lining (4), and connecting the open cut tunnel lining (4) with a cast-in-situ bored pile (3);
s7, pouring the concrete protection body (5), pouring a flow guide slope (7) with the direction consistent with that of the slope on the upper portion of the concrete protection body (5), laying a reinforcing mesh (6) on the surface layer of the concrete protection body (5), and firmly connecting the reinforcing mesh (6) with the steel guide pipe (1);
and S8, backfilling concrete in the foundation pit (12).
9. The construction method for the side slope open cut tunnel supporting structure according to claim 8, wherein in step S2, the front end of the high-pressure jet grouting reinforcement body (2) enters the bedrock (10) to be more than or equal to 0.5m;
and/or the presence of a gas in the gas,
in the step S2, the steel guide pipes (1) are arranged along a line, the distance between every two adjacent steel guide pipes (1) is less than or equal to 20cm, the intersection angle of the axis of each steel guide pipe (1) and a horizontal line is 20-30 degrees, and the inserted bedrock is more than or equal to 2m.
10. The construction method for the side slope open cut tunnel supporting structure according to claim 8 or 9, wherein in step S4, the soil body at the excavation position a is up to the elevation of the bottom surface of the inverted arch of the open cut tunnel lining (4), and the part of the high-pressure jet grouting reinforcement body (2) at the excavation surface position is correspondingly cut during the excavation process, so as to finally form the foundation pit (12).
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CN115419087A (en) * 2022-10-23 2022-12-02 重庆敏思岩土工程有限公司 Multilayer soil sliding rotary spraying reinforcement method

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