阅读说明：本技术 一种用于粘性土层管幕顶进的反力墙结构及施工方法 (Reaction wall structure for jacking cohesive soil layer pipe curtain and construction method ) 是由 袁齐虎 杨仲杰 安刚建 王叶斌 袁正璞 王尹 杨新安 富巨烨 余坤 余松 李路恒 于 2021-08-19 设计创作，主要内容包括：本发明提供一种用于粘性土层管幕顶进的反力墙结构及施工方法,反力墙包括隧道顶底板管幕反力墙和隧道侧墙管幕反力墙；两个隧道侧墙管幕反力墙设置于工作井后侧墙的两侧,用于对侧墙管幕进行顶进,隧道顶底板管幕反力墙设置于工作井的后侧墙处上沿,以对顶层管幕进行顶进,隧道顶底板管幕反力墙设置于工作井的后侧墙处下沿,用于对底层管幕进行顶进；采用板桩式作为反力墙主体结构,施工安装方便、工程造价低,隧道顶底板管幕反力墙由钢板桩和钢面板组成,隧道侧墙管幕反力墙由灌注桩和钢面板,有足够的强度和刚度,能保证结构在管幕顶进期间不被破坏,且能有效降低顶进反力作用下压缩回弹量,减小千斤顶有效冲程的损耗,提高顶进效率。(The invention provides a reaction wall structure for jacking a pipe curtain of a cohesive soil layer and a construction method, wherein the reaction wall comprises a tunnel top bottom plate pipe curtain reaction wall and a tunnel side wall pipe curtain reaction wall; the two tunnel side wall pipe curtain reaction walls are arranged on two sides of the rear side wall of the working well and used for jacking the side wall pipe curtains, the tunnel top bottom plate pipe curtain reaction wall is arranged on the upper edge of the rear side wall of the working well so as to jack the top layer pipe curtain, and the tunnel top bottom plate pipe curtain reaction wall is arranged on the lower edge of the rear side wall of the working well and used for jacking the bottom layer pipe curtain; the plate pile type reaction wall main body structure is adopted, construction and installation are convenient, construction cost is low, the tunnel top bottom plate pipe curtain reaction wall is composed of steel plate piles and steel panels, the tunnel side wall pipe curtain reaction wall is composed of cast-in-place piles and steel panels, and has enough strength and rigidity, so that the structure can be guaranteed not to be damaged during pipe curtain jacking, the compression resilience amount under the jacking reaction effect can be effectively reduced, the loss of the effective stroke of a jack is reduced, and jacking efficiency is improved.)

1. A reaction wall structure for jacking a cohesive soil layer pipe curtain is characterized in that the reaction wall comprises a tunnel top bottom plate pipe curtain reaction wall and a tunnel side wall pipe curtain reaction wall;

two tunnel side wall pipe curtain reaction wall sets up in the both sides of side wall behind the working well, tunnel side wall pipe curtain reaction wall is used for advancing in the top to side wall pipe curtain, tunnel side wall pipe curtain reaction wall includes:

the cast-in-place piles are arranged in undisturbed soil of the working well, and are distributed in parallel along the rear side wall of the working well to form a main body of the tunnel side wall pipe curtain reaction wall;

the steel panels are sequentially arranged on the cast-in-place pile according to the jacking sequence of the side wall pipe curtains of the tunnel, and the steel panels are arranged on one side of the cast-in-place pile corresponding to the jacking direction of the pipe curtains and used for arranging jacks;

the tunnel top and bottom plate pipe curtain reaction wall is arranged at the upper edge of the rear side wall of the working well and used for jacking the top layer pipe curtain; or the tunnel top and bottom plate pipe curtain reaction wall is arranged at the lower edge of the rear side wall of the working well and used for jacking the bottom pipe curtain;

tunnel top bottom plate pipe curtain counterforce wall includes:

the lower end of each steel sheet pile is anchored in undisturbed soil in the working well, and a plurality of steel sheet piles are distributed in parallel along the rear side wall of the working well so as to form a main body of the tunnel top and bottom plate pipe curtain reaction wall;

and the steel panel is arranged on one side of the steel sheet pile corresponding to the pipe curtain jacking direction and used for arranging a jack.

2. The counterforce wall structure for pipe curtain jacking of the cohesive soil layer as claimed in claim 1, wherein the length of the steel sheet pile is not less than 6m, and the depth of anchoring in undisturbed soil is not less than 4 m.

3. The counterforce wall structure for pipe curtain jacking of the cohesive soil layer as claimed in claim 1, wherein the burial depth of the cast-in-place pile is greater than the burial depth of the bottom pipe curtain by 4m, and the cast-in-place pile is gradually broken downwards along with the jacking sequence of the pipe curtain of the side wall of the tunnel.

4. The counterforce wall structure for pipe curtain jacking of the cohesive soil layer as claimed in claim 1, wherein a guide hole corresponding to the steel sheet pile is preset in undisturbed soil to guide the steel sheet pile to be anchored.

5. A reaction wall construction method for tube sheet jacking of cohesive soil layer, using the reaction wall structure for tube sheet jacking of cohesive soil according to claims 1 to 4, comprising:

step S1, respectively constructing at least two cast-in-place piles on two sides of the rear side wall of the working well, wherein the cast-in-place piles are arranged in the undisturbed soil of the working well and are distributed in parallel along the rear side wall of the working well to form a main body of the tunnel side wall pipe curtain reaction wall;

step S2, arranging steel sheet piles on the upper edge of the rear side wall of the working well, anchoring the lower ends of the steel sheet piles in undisturbed soil in the working well, and distributing a plurality of steel sheet piles in parallel along the rear side wall of the working well to form a main body of the tunnel top bottom plate pipe curtain reaction wall;

step S3, arranging a steel panel on one side of the steel sheet pile corresponding to the jacking direction of the pipe curtain, arranging a jack on the steel panel, and sequentially jacking the pipe curtain on the top layer through the jack;

step S4, after the top layer pipe curtain is jacked, removing the steel panel, pulling out the steel sheet pile, and excavating a working well;

step S5, sequentially jacking side wall pipe curtains along with excavation of a working well, sequentially arranging steel panels on the cast-in-place piles according to the jacking sequence of the side wall pipe curtains of the tunnel, arranging jacks on the steel panels, and sequentially jacking the side wall pipe curtains through the jacks, wherein the steel panels are arranged on one sides of the cast-in-place piles corresponding to the jacking direction of the pipe curtains;

step S6, along with the jacking of the side wall pipe curtain after the excavation of the working well, steel sheet piles are arranged on the lower edge of the rear side wall of the working well, the lower ends of the steel sheet piles are anchored in the undisturbed soil in the working well, and a plurality of steel sheet piles are distributed in parallel along the rear side wall of the working well to form a main body of the tunnel top bottom plate pipe curtain reaction wall;

step S7, arranging a steel panel on one side of the steel sheet pile corresponding to the jacking direction of the pipe curtain, arranging a jack on the steel panel, and sequentially jacking the pipe curtain at the bottom layer by the jack;

and step S7, after the bottom layer pipe curtain is jacked, removing the steel panel and pulling out the steel sheet pile to finish the pipe curtain jacking construction.

6. The method of claim 5, wherein the steel sheet pile has a length of not less than 6m and a depth of not less than 4m when anchored in undisturbed soil.

7. The method for constructing a reaction wall for jacking a pipe curtain of a cohesive soil layer as recited in claim 5, wherein the depth of burial of said cast-in-place pile is greater than the depth of burial of the pipe curtain of the bottom layer by 4m, and said cast-in-place pile is successively broken down in the sequence of jacking the pipe curtain of the side wall of the tunnel.

8. The method as claimed in claim 5, wherein a hole is formed in the undisturbed soil to guide the steel sheet pile to be anchored.

9. The method of claim 5, wherein the area of any one of the steel panels is 2 times larger than the cross-sectional area of the corresponding pipe screen.

10. The method of claim 5, wherein during excavation of the working well, the upper edge of the undisturbed soil on the side away from the pipe-roof advancing direction is flush with the upper edge of the reaction wall.

Technical Field

The invention belongs to the technical field of urban roads penetrated under tunnels, and particularly relates to a reaction wall structure for jacking a pipe curtain of a cohesive soil layer and a construction method.

Background

When an urban road is constructed, the road inevitably penetrates important buildings (structures) downwards, and in order to ensure the normal traffic of the existing road and the structural safety of the existing buildings (structures), a pipe curtain method is often adopted to support the space penetrating a tunnel downwards. The reaction force of the jack during jacking of the pipe curtain is usually provided by a reaction wall, and the reaction wall is a structure for providing reaction force for the jack during jacking of the pipe curtain and is sometimes called a backseat, a back or a back wall. Common counterforce walls include gravity backs, reinforced concrete backs, sheet pile backs and the like. The gravity type back is convenient to construct and low in construction cost, but cannot provide enough counter force; the jacking force provided by the reinforced concrete type back is heavier than that provided by a heavy-duty back, but the reinforced concrete type back is higher in manufacturing cost, fixed in position and large in required space, and a constructed tunnel lining is often used as a counter-force structure in actual engineering and is mainly used for jacking a large box culvert; the sheet pile type back is usually composed of high-strength steel plates, has high rigidity, simple construction and lower manufacturing cost, and can provide enough jacking counter force for jacking the pipe curtain.

In the pipe curtain jacking process, the reaction wall is required to be stable, once the reaction wall is damaged, the jacking engineering is suspended, and even jacking track deviation is caused, so that deviation rectification control cannot be performed. Meanwhile, aiming at the technical problems that in some areas, cohesive force is high when a cohesive soil stratum is not disturbed, foundation bearing capacity is high (about 220 KPa), how a sheet pile type reaction wall is stably anchored in a soil body and how the reaction wall is not damaged when a steel pipe curtain is jacked in, jacking efficiency is fully improved, and jacking progress of the steel pipe curtain is ensured, the method is urgently needed to be solved by technical personnel in the field.

Therefore, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a simple and stable reaction wall.

In order to achieve the above purpose, the invention provides the following technical scheme:

a reaction wall structure for jacking a cohesive soil layer pipe curtain is disclosed, wherein the reaction wall comprises a tunnel top bottom plate pipe curtain reaction wall and a tunnel side wall pipe curtain reaction wall;

two tunnel side wall pipe curtain reaction wall sets up in the both sides of side wall behind the working well, tunnel side wall pipe curtain reaction wall is used for advancing in the top to side wall pipe curtain, tunnel side wall pipe curtain reaction wall includes:

the cast-in-place piles are arranged in undisturbed soil of the working well, and are distributed in parallel along the rear side wall of the working well to form a main body of the tunnel side wall pipe curtain reaction wall;

the steel panels are sequentially arranged on the cast-in-place pile according to the jacking sequence of the side wall pipe curtains of the tunnel, and the steel panels are arranged on one side of the cast-in-place pile corresponding to the jacking direction of the pipe curtains and used for arranging jacks;

the tunnel top and bottom plate pipe curtain reaction wall is arranged at the upper edge of the rear side wall of the working well and used for jacking the top layer pipe curtain; or the tunnel top and bottom plate pipe curtain reaction wall is arranged at the lower edge of the rear side wall of the working well and used for jacking the bottom pipe curtain;

tunnel top bottom plate pipe curtain counterforce wall includes:

the lower end of each steel sheet pile is anchored in undisturbed soil in the working well, and a plurality of steel sheet piles are distributed in parallel along the rear side wall of the working well so as to form a main body of the tunnel top and bottom plate pipe curtain reaction wall;

and the steel panel is arranged on one side of the steel sheet pile corresponding to the pipe curtain jacking direction and used for arranging a jack.

In the reaction wall structure for pushing up the tube curtain of the cohesive soil layer, preferably, the length of the steel sheet pile is not less than 6m, and the depth of the steel sheet pile anchored in undisturbed soil is not less than 4 m.

In the reaction wall structure for pushing up the tube sheet of the cohesive soil layer as described above, preferably, the depth of burial of the cast-in-place pile is greater than the depth of burial of the tube sheet of the bottom layer by 4m, and the cast-in-place pile is successively broken down in accordance with the pushing-in sequence of the tube sheet of the tunnel side wall.

In the reaction wall structure for pushing up the tube sheet in the cohesive soil layer, preferably, a guide hole corresponding to the steel sheet pile is preset in undisturbed soil to guide the steel sheet pile to be anchored.

A reaction wall construction method for pushing a tube sheet into a cohesive soil layer, the reaction wall construction method using the reaction wall structure for pushing a tube sheet into a cohesive soil layer, the reaction wall construction method comprising:

step S1, respectively constructing at least two cast-in-place piles on two sides of the rear side wall of the working well, wherein the cast-in-place piles are arranged in the undisturbed soil of the working well and are distributed in parallel along the rear side wall of the working well to form a main body of the tunnel side wall pipe curtain reaction wall;

step S2, arranging steel sheet piles on the upper edge of the rear side wall of the working well, anchoring the lower ends of the steel sheet piles in undisturbed soil in the working well, and distributing a plurality of steel sheet piles in parallel along the rear side wall of the working well to form a main body of the tunnel top bottom plate pipe curtain reaction wall;

step S3, arranging a steel panel on one side of the steel sheet pile corresponding to the jacking direction of the pipe curtain, arranging a jack on the steel panel, and sequentially jacking the pipe curtain on the top layer through the jack;

step S4, after the top layer pipe curtain is jacked, removing the steel panel, pulling out the steel sheet pile, and excavating a working well;

step S5, sequentially jacking side wall pipe curtains along with excavation of a working well, sequentially arranging steel panels on the cast-in-place piles according to the jacking sequence of the side wall pipe curtains of the tunnel, arranging jacks on the steel panels, and sequentially jacking the side wall pipe curtains through the jacks, wherein the steel panels are arranged on one sides of the cast-in-place piles corresponding to the jacking direction of the pipe curtains;

step S6, along with the jacking of the side wall pipe curtain after the excavation of the working well, steel sheet piles are arranged on the lower edge of the rear side wall of the working well, the lower ends of the steel sheet piles are anchored in the undisturbed soil in the working well, and a plurality of steel sheet piles are distributed in parallel along the rear side wall of the working well to form a main body of the tunnel top bottom plate pipe curtain reaction wall;

step S7, arranging a steel panel on one side of the steel sheet pile corresponding to the jacking direction of the pipe curtain, arranging a jack on the steel panel, and sequentially jacking the pipe curtain at the bottom layer by the jack;

and step S7, after the bottom layer pipe curtain is jacked, removing the steel panel and pulling out the steel sheet pile to finish the pipe curtain jacking construction.

In the above method for constructing a reaction wall for pushing up a pipe-roof of a cohesive soil layer, it is preferable that the length of the steel sheet pile is not less than 6m, and the depth of anchoring in undisturbed soil is not less than 4 m.

In the method for constructing a reaction wall for pushing up a pipe curtain of a cohesive soil layer as described above, it is preferable that the depth of burial of the cast-in-place pile is greater than the depth of burial of the pipe curtain of the bottom layer by 4m, and the cast-in-place pile is successively broken down in accordance with the pushing-up sequence of the pipe curtain of the tunnel side wall.

In the above method for constructing a reaction wall for pushing a pipe curtain into a cohesive soil layer, preferably, a guide hole corresponding to the steel sheet pile is preset in undisturbed soil to guide the steel sheet pile to be anchored.

In the above reaction wall construction method for pushing up the pipe curtain of the cohesive soil layer, preferably, the area of any one of the steel panels is 2 times larger than the area of the corresponding pipe curtain cross section.

In the above reaction wall construction method for pushing up the pipe curtain of the cohesive soil layer, preferably, during excavation of the working well, the upper edge of the undisturbed soil on the side away from the pipe curtain pushing direction is flush with the upper edge of the reaction wall.

Has the advantages that: the pipe curtain reaction wall of the tunnel top and bottom plate is composed of the steel sheet piles and the steel panel, and the pipe curtain reaction wall of the tunnel side wall is composed of the cast-in-place piles and the steel panel, so that on one hand, the pipe curtain reaction wall has enough strength and rigidity, the structure can be ensured not to be damaged during the jacking of the pipe curtain, the compression rebound quantity under the action of jacking reaction force can be effectively reduced, the loss of the effective stroke of the jack is reduced, and the jacking efficiency is improved; on the other hand, the counterforce wall material is uniform in quality and flat and straight in surface, so that the uneven compression when the wall material bears larger counterforce can be avoided, the jack is eccentric, the jacking force loss is caused, and the jacking precision of the pipe curtain is improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. Wherein:

FIG. 1 is a plan view of a tube curtain reaction wall in accordance with an embodiment of the present invention;

FIG. 2 is a schematic view of the arrangement of the tube curtain reaction wall of the tunnel side wall in the embodiment of the invention;

FIG. 3 is a schematic diagram of the arrangement of the reaction wall on the top of the tunnel according to the embodiment of the invention;

fig. 4 is a schematic layout of the reaction wall at the bottom of the tunnel in the embodiment of the invention.

In the figure: 1. a working well; 2. a top tube sheet; 3. a steel panel; 4. filling piles; 5. undisturbed soil; 6. steel sheet piles; 7. a cushion layer and a slideway; 8. a side wall pipe curtain; 9. the bottom tube sheet.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.

In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are for convenience of description of the present invention only and do not require that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. The terms "connected" and "connected" used herein should be interpreted broadly, and may include, for example, a fixed connection or a detachable connection; they may be directly connected or indirectly connected through intermediate members, and specific meanings of the above terms will be understood by those skilled in the art as appropriate.

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

As shown in fig. 1-4, a reaction wall structure for jacking a pipe curtain of a cohesive soil layer comprises a tunnel top bottom plate pipe curtain reaction wall and a tunnel side wall pipe curtain reaction wall; two tunnel side wall pipe curtain reaction walls set up in the both sides of side wall behind the working well 1 for 8 carry out the top advance to side wall pipe curtains, and tunnel side wall pipe curtain reaction wall includes: the cast-in-place piles 4 are arranged in undisturbed soil 5 of the working well 1, and are distributed in parallel along the rear side wall of the working well 1 to form a main body of the tunnel side wall pipe curtain reaction wall; steel facing 3, steel facing 3 advance the order according to the top of tunnel side wall pipe curtain 8 and set gradually on bored concrete pile 4, and steel facing 3 sets up in the one side of the corresponding pipe curtain top of bored concrete pile 4 and advances the direction for arrange the jack.

The tunnel top and bottom plate pipe curtain reaction wall is arranged at the upper edge of the rear side wall of the working well 1 so as to jack the top layer pipe curtain 2; or the tunnel top and bottom plate pipe curtain reaction wall is arranged at the lower edge of the rear side wall of the working well 1 and is used for jacking the bottom pipe curtain 9; the length of the tunnel top and bottom plate pipe curtain reaction wall is matched with the length of the rear side wall of the working well 1, so that all top layer pipe curtains 2 or bottom layer pipe curtains 9 can be jacked; tunnel top bottom plate pipe curtain counterforce wall includes: the lower end of the steel sheet pile 6 is anchored in undisturbed soil 5 in the working well 1, and a plurality of steel sheet piles 6 are distributed in parallel along the rear side wall of the working well 1 to form a main body of the tunnel top and bottom plate pipe curtain reaction wall; and the steel panel 3 is arranged on one side of the steel sheet pile 6 corresponding to the pipe curtain jacking direction and used for arranging a jack.

Carry out the setting of counterforce wall according to the excavation progress of working well 1, tunnel top bottom plate pipe curtain counterforce wall advances in to top layer pipe curtain 2 and bottom pipe curtain 9 respectively, and tunnel top bottom plate pipe curtain counterforce wall comprises steel sheet pile 6 and steel sheet panel 3, can demolish fast along with the engineering progress, improves the construction progress, and simple structure effectively reduces engineering cost

Carry out the jacking through tunnel side wall pipe curtain reaction wall to side wall pipe curtain 8, tunnel side wall pipe curtain reaction wall main part is bored concrete pile 4, stable in structure, and in the work progress, along with the excavation of working well 1 breaks away, need not apply repeatedly and do, simple structure effectively reduces engineering cost.

In another alternative embodiment of the present application, the length of the steel sheet pile 6 is not less than 6m, and the depth of anchoring in undisturbed soil 5 is not less than 4 m. Preferably, the length of the steel sheet pile 6 is 6m, and the depth of anchoring in the undisturbed soil 5 is 4-5m, such as 4m, 4.5m and 5 m; and a cushion layer and a slideway are arranged in the working well 1 corresponding to the part, which is not anchored, of the steel sheet pile 6, so that axial deviation cannot occur in the pipe curtain jacking process.

In another alternative embodiment of the present application, the depth of burial of cast-in-place pile 4 is greater than the burial depth 4m, e.g. 4.5m, 5m, of bottom tube sheet 9, and is broken down successively with the advancement of tunnel side wall tube sheet 8. The cast-in-place pile 4 is constructed by concrete, the buried depth is larger than that of the bottom pipe curtain 9, the stability of the cast-in-place pile is guaranteed, and more stable supporting force can be given to the pipe curtain jacking.

In another optional embodiment of the present application, a guide hole corresponding to the steel sheet pile 6 is preset in the undisturbed soil 5 to guide the steel sheet pile 6 to anchor. The anchoring of the steel sheet pile 6 is guided through the preset guide hole, the steel sheet pile 6 is driven into the guide hole, and the difficult problem of sheet pile type reaction wall installation caused by overhigh bearing capacity of the cohesive soil foundation can be effectively solved.

The invention also provides a reaction wall construction method for jacking the cohesive soil layer pipe curtain, which comprises the following steps:

step S1, the position of the working well 1 is defined, at least two cast-in-place piles 4 are respectively constructed on two sides of the rear side wall of the working well 1, the cast-in-place piles 4 are arranged in the undisturbed soil 5 of the working well 1 and are distributed in parallel along the rear side wall of the working well 1, and therefore the main body of the tunnel side wall pipe curtain reaction wall is formed.

And step S2, arranging steel sheet piles 6 on the upper edge of the rear wall of the working well, anchoring the lower ends of the steel sheet piles 6 in undisturbed soil 5 in the working well 1, and distributing a plurality of steel sheet piles 6 in parallel along the rear side wall of the working well 1 to form a main body of the tunnel top-bottom plate pipe curtain reaction wall.

Step S3, arranging a steel panel 3 on one side of the steel sheet pile 6 corresponding to the jacking direction of the pipe curtain, arranging a jack on the steel panel 3, and sequentially jacking the top layer pipe curtain 2 through the jack.

And step S4, after the top layer pipe curtain 2 is jacked, removing the steel panel 3, pulling out the steel sheet pile 6, and excavating the working well 1.

Step S5, along with the excavation of working well 1, advancing in proper order the advancing of lateral wall pipe curtain 8, according to the advancing order in proper order of tunnel lateral wall pipe curtain 8 set up steel sheet 3 on bored concrete pile 4, steel sheet 3 sets up in the one side of bored concrete pile 4 corresponding pipe curtain advancing direction, arranges the jack on steel sheet 3, advances lateral wall pipe curtain 8 through jack in proper order.

Step S6, the jacking of the side wall pipe curtain 8 is completed along with the excavation of the working well 1, the steel sheet piles 6 are arranged on the lower edge of the rear side wall of the working well 1, the lower ends of the steel sheet piles 6 are anchored in the undisturbed soil 5 in the working well 1, and the steel sheet piles 6 are distributed in parallel along the rear side wall of the working well 1 to form a main body of the tunnel top bottom plate pipe curtain reaction wall.

Step S7, arranging a steel panel 3 on one side of the steel sheet pile 6 corresponding to the jacking direction of the pipe curtain, arranging a jack on the steel panel 3, and sequentially jacking the bottom pipe curtain 9 through the jack.

And step S7, after the jacking of the bottom layer pipe curtain 9 is finished, removing the steel panel 3 and pulling out the steel sheet pile 6 to finish the pipe curtain jacking construction.

Beat earlier and establish bored concrete pile 4, form the stable brace that advances to 8 tops of side wall pipe curtains through bored concrete pile 4 and original state soil 5, then carry out the tunnel top bottom plate pipe curtain counter-force wall construction that corresponds top layer pipe curtain 2, carry out the preliminary excavation of working well 1 after the construction is accomplished, 1 vertical excavation 2m of working well promptly to lay bed course and slide 7, and advance with this top of carrying out top layer pipe curtain 2, and demolish after top layer pipe curtain 2 construction is accomplished.

Continuing to excavate the working well 1, jacking the side wall pipe curtain 8 along with the excavation progress (paving a cushion layer and a slide 7 corresponding to the progress) in the excavation process, after the excavation of the working well 1 is finished, also jacking the side wall pipe curtain 8, then setting a tunnel top bottom plate pipe curtain reaction wall corresponding to the bottom pipe curtain 9 for construction, and jacking the bottom pipe curtain 9; the reaction wall can be arranged according to the excavation progress of the working well 1, the tunnel top and bottom plate pipe curtain reaction wall respectively jacks the top layer pipe curtain 2 and the bottom layer pipe curtain 9, and the tunnel top and bottom plate pipe curtain reaction wall is composed of the steel sheet piles 6 and the steel panel 3, can be quickly dismantled along with the progress of the project, improves the construction progress, has a simple structure, and effectively reduces the construction cost; in the excavation process of the working well 1, the cast-in-place pile 4 is broken according to the construction progress, the construction is simple and effective, and the efficiency is high.

In another alternative embodiment of the present application, in the above method, the length of the steel sheet pile 6 is not less than 6m, and the depth of anchoring in the undisturbed soil 5 is not less than 4 m. Preferably, the length of the steel sheet pile 6 is 6m, and the depth of anchoring in the undisturbed soil 5 is 4-5m, such as 4m, 4.5m and 5 m; and a cushion layer and a slideway are arranged in the working well 1 corresponding to the part, which is not anchored, of the steel sheet pile 6, so that axial deviation cannot occur in the pipe curtain jacking process.

The length of the steel sheet pile 6 is not less than 6m, and the depth of anchoring in undisturbed soil 5 is not less than 4 m. Preferably, the length of the steel sheet pile 6 is 6m, and the depth of anchoring in the undisturbed soil 5 is 4-5m, such as 4m, 4.5m and 5 m; and a cushion layer and a slideway are arranged in the working well 1 corresponding to the part, which is not anchored, of the steel sheet pile 6, so that axial deviation cannot occur in the pipe curtain jacking process.

In another alternative embodiment of the present application, the depth of burial of cast-in-place pile 4 is greater than the burial depth 4m, e.g. 4.5m, 5m, of bottom tube sheet 9, and is broken down successively with the advancement of tunnel side wall tube sheet 8. The cast-in-place pile 4 is constructed by concrete, the buried depth is larger than that of the bottom pipe curtain 9, the stability of the cast-in-place pile is guaranteed, and more stable supporting force can be given to the pipe curtain jacking.

In another optional embodiment of the present application, a guide hole corresponding to the steel sheet pile 6 is preset in the undisturbed soil 5 to guide the steel sheet pile 6 to anchor. The anchoring of the steel sheet pile 6 is guided through the preset guide hole, the steel sheet pile 6 is driven into the guide hole, and the difficult problem of sheet pile type reaction wall installation caused by overhigh bearing capacity of the cohesive soil foundation can be effectively solved. Because the cohesive soil foundation bearing capacity of the working well 1 is larger, the steel sheet pile 6 is driven by adopting an independent driving method until the steel sheet pile 6 curtain of the top pipe curtain reaction wall is finished;

in some embodiments, during the specific jacking process of the top layer pipe curtain 2 or the bottom layer pipe curtain 9, the steel panels 3 are sequentially arranged on the steel sheet piles 6 at corresponding positions along with the jacking progress of the steel panels 3. The steel panel 3 is provided with double layers to enhance jacking reaction force support.

In another alternative embodiment of the present application, the area of any one of the steel panels 3 is greater than 2 times the cross-sectional area of its corresponding tube sheet, and may be 3 times the cross-sectional area of the tube sheet. The steel panel 3 adopts double-deck 20 ~ 30mm steel panel 3, can support the jack, guarantees the stability of jacking in-process.

In another alternative embodiment of the present application, during the excavation of the working well 1, the upper edge of the undisturbed soil 5 on the side away from the pipe curtain jacking direction is flush with the upper edge of the counterforce wall. When working well 1 and pipe curtain construction, keep away from the original state soil 5 of pipe curtain jacking direction one side to the reaction wall and excavate in step, this side original state soil 5 go up along flushing with the last edge of reaction wall, guarantee that the reaction wall is supported by original state soil 5, improve support stability.

In summary, the present invention provides a reaction wall structure for jacking a pipe curtain of a clay layer and a construction method thereof, two cast-in-place piles 4 are constructed on two sides of the rear side wall of a working well 1 of a pipe curtain tunnel to be jacked, the depth of each cast-in-place pile 4 needs to exceed the pipe curtain burial depth of the bottom of the tunnel by 4-5m, then a tunnel top bottom plate pipe curtain counter-force wall is constructed on the upper edge of the rear side wall of the working well 1, vertically excavating 2m in the working well 1, arranging a double-layer 20mm steel panel 33 on the corresponding steel sheet pile 6 so as to jack the steel sheet pile 6 into the tunnel top pipe curtain, wherein the steel sheet pile 6 is a Larsen IV-type steel sheet pile 6, because the cohesive soil foundation bearing capacity of the working well 1 is larger, the construction of the steel sheet pile 6 needs to be preformed with hole guiding treatment and adopts a separate driving method until the steel sheet pile 6 curtain of the top pipe curtain reaction wall is completed, according to the jacking sequence of the pipe curtains, the steel panels 3 at the corresponding positions of the steel pipes to be jacked are laid in sequence; pulling out the tunnel top and bottom plate pipe curtain reaction wall corresponding to the top pipe curtain, excavating the working well 1, jacking the side wall pipe curtain 8 of the tunnel according to the excavation progress, and sequentially breaking the cast-in-place piles 4 downwards according to the excavation position; after the excavation of the working well 1 is finished, the tunnel top bottom plate pipe curtain reaction wall corresponding to the bottom pipe curtain 9 is arranged, the bottom pipe curtain 9 is jacked, the steel panel 3 is sequentially arranged according to the jacking sequence, and the construction of the tunnel bottom plate pipe curtain is finished. It should be understood that the above description is only exemplary, and the embodiments of the present application do not limit the present invention.

The above description is only exemplary of the invention and should not be taken as limiting the invention, as any modification, equivalent replacement, or improvement made within the spirit and principle of the invention is intended to be covered by the appended claims.