阅读说明：本技术 一种临地铁超大基坑永临结合型支护体系及其方法 (Permanent-temporary combined supporting system and method for extra-large foundation pit near subway ) 是由 王廷征 梁斌 徐光明 刘京瑞 郭洪新 王宇 李宝泉 王明鸿 于 2020-06-09 设计创作，主要内容包括：本发明提供了一种临地铁超大基坑永临结合型支护体系及其方法,主体结构一侧设置有楼板,楼板的上方设置有钢筋混凝土牛腿,钢筋混凝土牛腿的一侧安装固定端,钢筋混凝土牛腿与固定端之间设置有轴力计,固定端的一侧安装有第二节段,第二节段的一侧安装有第一节段,第一节段的一侧设置有活络接头端,活络接头端的一侧设置有围檩,围檩的一侧设置有支护桩,支护桩的一侧安装有腰梁,支护桩的另一侧为岩体结构,通过钢管结构支撑梁一端通过围檩与支护桩连接,另一端通过钢筋混凝土牛腿与主体结构连接,既能严格限制基坑的位移,确保地铁的正常运营,又不需要拆除临时支护,提高了工作效率,缩短了工期,降低了施工成本,取得了较好的经济效益。(The invention provides a permanent temporary combined supporting system of an ultra-large foundation pit near a subway and a method thereof, wherein one side of a main body structure is provided with a floor slab, a reinforced concrete corbel is arranged above the floor slab, one side of the reinforced concrete corbel is provided with a fixed end, an axial force meter is arranged between the reinforced concrete corbel and the fixed end, one side of the fixed end is provided with a second segment, one side of the second segment is provided with a first segment, one side of the first segment is provided with an adjustable joint end, one side of the adjustable joint end is provided with a surrounding purlin, one side of the surrounding purlin is provided with a supporting pile, one side of the supporting pile is provided with a waist beam, the other side of the supporting pile is of a rock mass structure, one end of the supporting beam is connected with the supporting pile through the surrounding purlin, the other end of the supporting beam is connected with the main body structure through the reinforced concrete corbel, the working efficiency is improved, the construction period is shortened, the construction cost is reduced, and better economic benefit is obtained.)

1. A permanent-faced combined supporting system for an ultra-large foundation pit faced with a subway is characterized by comprising a foundation pit, a main body structure is arranged in the foundation pit, a floor slab is arranged on one side of the main body structure, a reinforced concrete corbel is arranged above the floor slab, a fixed end is arranged at one side of the reinforced concrete bracket, an axial force meter is arranged between the reinforced concrete bracket and the fixed end, a second section is arranged at one side of the fixed end, a first section is arranged at one side of the second section, a connecting flange is arranged between the second section and the first section, one side of the first section is provided with an adjustable joint end, one side of the loose joint end is provided with an enclosing purlin, one side of the enclosing purlin is provided with a supporting pile, one side of the supporting pile is provided with a waist beam, the other side of the support pile is of a rock mass structure, and one side of the rock mass structure is of a subway tunnel.

2. The permanent-temporary combined supporting system for the extra-large foundation pit near the subway as claimed in claim 1, wherein: the fixed end, the movable joint end, the first section and the second section are connected through a connecting flange to form a steel pipe structure supporting beam, and the steel pipe structure supporting beam is parallel to the main structure floor slab.

3. The permanent-temporary combined supporting system for the extra-large foundation pit near the subway as claimed in claim 1, wherein: the purlin and the reinforced concrete bracket are located on the same horizontal line.

4. The permanent-temporary combined supporting system for the extra-large foundation pit near the subway as claimed in claim 1, wherein: the supporting piles are jet grouting piles.

5. The permanent-temporary combined supporting system for the extra-large foundation pit near the subway as claimed in claim 1, wherein: the reinforced concrete bracket is formed by pouring reinforcing steel bars and concrete, and the strength grade of the concrete of the reinforced concrete bracket is greater than or equal to that of the concrete of a floor slab.

6. The permanent-temporary combined supporting system for the extra-large foundation pit near the subway as claimed in claim 1, wherein: the underground space structure of the main structure is at least one layer, the main structure is a constructed main structure, and the main structure has the condition of being used as a steel pipe support.

7. The permanent-temporary combined supporting system for the extra-large foundation pit near the subway as claimed in claim 1, wherein: the waist rail is fixedly connected with the support piles through steel bar welding, and the enclosing purlin is of a reinforced concrete structure.

8. The permanent-temporary combined supporting system for the extra-large foundation pit near the subway as claimed in claim 1, wherein: the axial force meter is used for monitoring stress.

9. A permanent-temporary combined supporting method for an extra-large foundation pit near a subway comprises the following steps:

s1, arranging support piles, performing jet grouting pile construction on the periphery of the foundation pit, and arranging the support piles;

s2, constructing a main structure, determining a foundation pit area with large influence on subway operation through mechanical calculation, reserving a soil body of the area, reserving a soil platform, and excavating earth and constructing the main structure of the foundation pit far away from the subway section according to the principle of distance to near;

s3, constructing a reinforced concrete corbel, positioning the corbel, binding reinforcing steel bars and pre-embedding an anchor plate according to a design drawing, wherein the strength grade of reinforced concrete corbel concrete is more than or equal to that of floor slab concrete;

s4, constructing the enclosing purlin, excavating soil, and excavating the first layer of excavation elevation to the bottom position of the enclosing purlin;

s5, constructing a waist beam, constructing a reinforced concrete waist beam, welding a waist beam steel bar on the jet grouting pile, binding the steel bar according to the design requirement, and pouring concrete;

s6, mounting the axial force meter, and connecting the axial force meter with the bracket in a welding mode;

s7, splicing and installing the steel pipe structure supporting beam, namely pre-splicing the steel pipe structure supporting beam by using an automobile crane, a tower crane and a manual matching mode, connecting a first section and a second section through a connecting flange, connecting a fixed end and a movable joint end to two ends respectively, installing the steel pipe structure supporting beam after the strength of concrete of the enclosing purlin reaches 80% of the designed strength, connecting the fixed end with a reinforced concrete bracket, and connecting the movable joint end with the enclosing purlin;

s8, constructing soil bodies, constructing the next layer of soil body for excavation, and repeating the steps S4-S7 until the foundation pit is excavated to the designed bottom elevation;

s9, reserving a soil platform for construction, and constructing a main structure cushion layer, a bottom plate and an outer wall at the reserved soil platform;

s10, performing waterproof and heat-insulating construction, namely performing waterproof and heat insulation on the outer wall of the basement, and particularly emphasizing waterproof treatment on the joint of the steel pipe support and the surrounding purlin;

s11, arranging a backfill groove, and backfilling a fertilizer groove between the outer wall and the support pile;

s12, removing the steel pipe structure support beam, and removing the steel pipe support and the reinforced concrete corbel of the layer after the outer wall concrete identical condition test block meets the design requirement;

and S13, sequentially constructing the main structure of the previous layer, and repeating the steps S9-S12 until the elevation of the main structure reaches the reserved earth platform elevation.

Technical Field

The invention relates to the technical field of ship cleaning, in particular to a permanent temporary combined supporting system for an extra-large foundation pit near a subway.

Background

With the continuous advance of urbanization, underground spaces with various purposes are increasingly developed and utilized in various big cities in China, and with the mass construction of middle-high-rise and super-high-rise buildings, a large number of super-large foundation pit projects emerge, in the foundation pit projects, the protection of existing underground pipelines, underground buildings, peripheral buildings and the like becomes a problem which is increasingly concerned by people, particularly, in recent years, a new problem that super-large foundation pit projects are adjacent to underground projects such as subway tunnels and the like is frequently presented, subways have strict requirements on the displacement after the soil body of the foundation pits around the tunnels is unloaded, in a common construction process, a foundation pit supporting project belongs to a temporary construction measure, the construction is required to be carried out after the gap between the foundation pit and an outer wall of an underground structure is backfilled, the construction material and social resources are greatly wasted, the dismantling work is complicated, and the field construction amount is large, the construction period progress is influenced, so that a new supporting system which can reduce construction steps, reduce engineering cost and ensure the safety of an oversized foundation pit is needed to be designed. The system has a series of advantages of environmental protection, resource saving, construction period saving and the like, and can effectively promote the sustainable development of urban construction.

Disclosure of Invention

The embodiment of the invention provides a permanent temporary combined supporting system for an extra-large foundation pit near a subway, which is connected with a main body structure through a reinforced concrete bracket, can strictly limit the displacement of the foundation pit, ensures the normal operation of the subway, does not need to dismantle a temporary support, and solves the problems of long construction period and foundation pit displacement caused by the fact that backfilling needs to be dismantled after foundation pit construction is completed in foundation pit engineering.

In view of the above problems, the technical solution proposed by the present invention is:

the utility model provides a face subway super large foundation ditch and face convolution type supporting system forever, includes: the foundation ditch, the inside of foundation ditch is provided with major structure, major structure one side is provided with the floor, the top of floor is provided with the reinforced concrete bracket, the axle power meter is installed to one side of reinforced concrete bracket, the stiff end is installed to one side of axle power meter, the second festival section is installed to one side of stiff end, first festival section is installed to one side of second festival section, the second festival section with be provided with flange between the first festival section, one side of first festival section is provided with loose joint end, one side of loose joint end is provided with encloses the purlin, one side of enclosing the purlin is provided with a fender pile, one side of fender pile is the rock mass structure, one side of rock mass structure is subway tunnel.

Furthermore, the fixed end, the loose joint end, the first section and the second section are connected through a connecting flange to form a steel pipe structure supporting beam, and the steel pipe structure supporting beam is parallel to the main structure floor slab.

Furthermore, the purlin and the reinforced concrete bracket are located on the same horizontal line.

Furthermore, the supporting piles are jet grouting piles.

Furthermore, the reinforced concrete bracket is formed by pouring reinforcing steel bars and concrete, and the strength grade of the concrete of the reinforced concrete bracket is greater than or equal to that of the concrete of the floor slab.

Furthermore, the underground space structure of the main body structure is at least one layer, and the main body structure is a constructed main body structure and has a condition of being used as a steel pipe support.

Furthermore, the waist rail is fixedly connected with the support piles through steel bar welding, and the purlin is of a reinforced concrete structure.

Further, the axial force meter is used for monitoring stress.

The embodiment of the invention also provides a permanent-temporary combined supporting method for the extra-large foundation pit near the subway, which comprises the following steps:

s1, arranging support piles, performing jet grouting pile construction on the periphery of the foundation pit, and arranging the support piles;

s2, constructing a main structure, determining a foundation pit area with large influence on subway operation through mechanical calculation, reserving a soil body of the area, reserving a soil platform, and excavating earth and constructing the main structure of the foundation pit far away from the subway section according to the principle of distance to near;

s3, constructing a reinforced concrete corbel, positioning the corbel, binding reinforcing steel bars and pre-embedding an anchor plate according to a design drawing, wherein the strength grade of reinforced concrete corbel concrete is more than or equal to that of floor slab concrete;

s4, constructing the enclosing purlin, excavating soil, and excavating the first layer of excavation elevation to the bottom position of the enclosing purlin;

s5, constructing a waist beam, constructing a reinforced concrete waist beam, welding a waist beam steel bar on the jet grouting pile, binding the steel bar according to the design requirement, and pouring concrete;

s6, mounting the axial force meter, and connecting the axial force meter with the bracket in a welding mode;

s7, splicing and installing the steel pipe structure supporting beam, namely pre-splicing the steel pipe structure supporting beam by using an automobile crane, a tower crane and a manual matching mode, connecting a first section and a second section through a connecting flange, connecting a fixed end and a movable joint end to two ends respectively, installing the steel pipe structure supporting beam after the strength of concrete of the enclosing purlin reaches 80% of the designed strength, connecting the fixed end with a reinforced concrete bracket, and connecting the movable joint end with the enclosing purlin;

s8, constructing soil bodies, constructing the next layer of soil body for excavation, and repeating the steps S4-S7 until the foundation pit is excavated to the designed bottom elevation;

s9, reserving a soil platform for construction, and constructing a main structure cushion layer, a bottom plate and an outer wall at the reserved soil platform;

s10, performing waterproof and heat-insulating construction, namely performing waterproof and heat insulation on the outer wall of the basement, and particularly emphasizing waterproof treatment on the joint of the steel pipe support and the surrounding purlin;

s11, arranging a backfill groove, and backfilling a fertilizer groove between the outer wall and the support pile;

s12, removing the steel pipe structure support beam, and removing the steel pipe support and the reinforced concrete corbel of the layer after the outer wall concrete identical condition test block meets the design requirement;

and S13, sequentially constructing the main structure of the previous layer, and repeating the steps S9-S12 until the elevation of the main structure reaches the reserved earth platform elevation.

Compared with the prior art, the invention has the beneficial effects that:

a steel tube structure supporting beam one end is connected with a fender pile through enclosing the purlin, and the other end passes through reinforced concrete bracket and is connected with major structure, can restrict the displacement of foundation ditch strictly, ensures the normal operation of subway, need not demolish interim support again, has improved work efficiency, has shortened the time limit for a project, has reduced construction cost, has gained better economic benefits.

The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.

Drawings

Fig. 1 is a schematic structural view of a permanent temporary combined supporting system of an extra large foundation pit near a subway disclosed in the embodiment of the invention;

fig. 2 is a schematic view of a permanent temporary combined supporting system mounting structure of an extra large foundation pit near a subway disclosed in the embodiment of the invention;

fig. 3 is a schematic flow chart of a permanent temporary combined supporting method for an extra large foundation pit near a subway, which is disclosed by the embodiment of the invention.

Reference numerals:

1-a floor slab; 2-reinforced concrete corbels; 3-fixing end; 4-a connecting flange; 5-a first segment; 6-loose joint end; 7-enclosing purlin; 8-supporting piles; 9-rock mass structure; 10-subway tunnels; 11-a second segment; 12-a foundation pit; 13-a body structure; 14-waist rail; 15-axial force meter.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

Referring to the attached drawings 1-2, the foundation pit comprises a foundation pit 12, a main structure 13 is arranged inside the foundation pit 12, at least one layer of underground space structure of the main structure 13 is provided, the main structure 13 is a constructed main structure 13 and has a steel pipe supporting condition, a floor slab 1 is arranged on one side of the main structure 13, a reinforced concrete corbel 2 is arranged above the floor slab 1, the reinforced concrete corbel 2 is formed by pouring reinforcing steel bars and concrete, the concrete strength grade of the reinforced concrete corbel 2 is greater than or equal to the concrete strength grade of the floor slab 1, a fixing end 3 is arranged on one side of the reinforced concrete corbel 2, the fixing end 3 is used for connecting the reinforced concrete corbel 2 with a steel pipe structure supporting beam formed by connecting the fixing end 3, the loose joint end 6, the first segment 5 and the second segment 11 through a connecting flange 4, an axial force meter 15 is arranged between the reinforced concrete corbel 2 and the fixed end 3, the axial force meter 15 is used for monitoring stress, a second section 11 is arranged on one side of the fixed end 3, a first section 5 is arranged on one side of the second section 11, a connecting flange 4 is arranged between the second section 11 and the first section 5, the number of sections is selected according to the actual construction condition, an adjustable joint end 6 is arranged on one side of the first section 5, the adjustable joint end 6 is used for connecting the fixed end 3, the adjustable joint end 6, the first section 5 and the second section 11 through the connecting flange 4 to form a steel pipe structure supporting beam which is connected with the purlin 7, the purlin 7 and the reinforced concrete corbel 2 are located on the same horizontal line to form vertical support, the support is more stable, a supporting pile 8 is arranged on one side of the purlin 7, the supporting piles 8 are jet grouting piles, a waist beam 14 is installed on one side of each supporting pile 8, the waist beam 14 is fixedly connected with the supporting piles 8 through steel bar welding, the waist beam 14 connects the supporting piles 8 into a whole body, a steel pipe structure supporting beam is convenient for supporting a foundation pit 12, the purlin 7 is of a reinforced concrete structure, the other side of each supporting pile 8 is of a rock mass structure 9, one side of the rock mass structure 9 is of a subway tunnel 10, the fixed end 3, the loose joint end 6, the first segment 5 and the second segment 11 are connected through a connecting flange 4 to form a steel pipe structure supporting beam, the steel pipe structure supporting beam is parallel to the floor 1 of the main structure 13, and the main structure 13 and the supporting piles 8 are connected through the fixed end 3, the loose joint end 6, the first segment 5 and the second segment 11 which are connected through the connecting flange 4, the displacement of the foundation pit 12 can be strictly limited, the normal operation of the subway is ensured, and the temporary support does not need to be removed, so that the combined supporting system permanently facing the subway super-large foundation pit 12 has the effects of improving the working efficiency, shortening the construction period, reducing the construction cost and strictly limiting the displacement of the foundation pit 12.

Referring to the attached figure 3, the permanent-temporary combined supporting method for the extra-large underground foundation pit 12 comprises the following steps:

s1, arranging the support piles 8, performing jet grouting pile construction on the periphery of the foundation pit 12, and arranging the support piles 8;

s2, constructing the main structure 13, determining a foundation pit 12 area with large influence on subway operation through mechanical calculation, reserving soil bodies in the area, reserving soil platforms, and excavating earth and constructing the main structure 13 on the foundation pit 12 far away from the subway section according to the principle of distance to near;

s3, constructing a reinforced concrete bracket 2, positioning the bracket, binding reinforcing steel bars and pre-embedding anchor plates according to a design drawing, wherein the concrete strength grade of the reinforced concrete bracket 2 is greater than or equal to that of a floor slab 1;

s4, constructing the enclosing purlin 7, excavating soil, and excavating the first layer of excavation elevation to the bottom of the enclosing purlin 7;

s5, constructing the wale 14, constructing the reinforced concrete wale 14, welding the steel bars of the wale 14 on the jet grouting pile, binding the steel bars according to design requirements, and pouring concrete;

s6, mounting the axial force meter 15, and connecting the axial force meter 15 and the bracket in a welding mode;

s7, splicing and installing the steel pipe structure supporting beam, namely pre-splicing the steel pipe structure supporting beam by using an automobile crane, a tower crane and a manual matching mode, connecting a first section 5 and a second section 11 through a connecting flange 4, respectively connecting a fixed end 3 and an adjustable joint end 6 at two ends, installing the steel pipe structure supporting beam after the concrete strength of an enclosing purlin 7 reaches 80% of the design strength, connecting the fixed end 3 with a reinforced concrete corbel 2, and connecting the adjustable joint end 6 with the enclosing purlin 7;

s8, constructing soil, excavating the next layer of soil in sequence, and repeating the steps S4-S7 until the foundation pit 12 is excavated to the designed bottom elevation;

s9, reserving a soil platform for construction, and constructing a cushion layer, a bottom plate and an outer wall of the main body structure 13 at the reserved soil platform;

s10, performing waterproof and heat-insulating construction, namely performing waterproof and heat insulation on the outer wall of the basement, and particularly emphasizing waterproof treatment on the joint of the steel pipe support and the surrounding purlin 7;

s11, arranging a backfill groove, and backfilling a fertilizer groove between the outer wall and the support pile 8;

s12, removing the steel pipe structure support beam, and removing the steel pipe support and the reinforced concrete corbel 2 on the layer after the outer wall concrete same condition test block meets the design requirement;

and S13, sequentially constructing the main structure 13 on the previous layer, and repeating the steps S9-S12 until the elevation of the main structure 13 reaches the reserved soil table elevation.

The method comprises the following specific implementation steps:

carrying out jet grouting pile construction on the periphery of a foundation pit 12, setting a supporting pile 8, determining a foundation pit 12 area with large influence on subway operation through mechanical calculation, reserving soil body of the area, reserving a soil bench, carrying out earthwork excavation on the foundation pit 12 far away from a subway section according to the principle of distance to near, constructing a main structure 13, carrying out bracket positioning, reinforcing steel bar binding and anchor plate pre-embedding according to design drawing, excavating the soil body, constructing a reinforced concrete waist beam 14 from a first layer of excavation elevation to the bottom position of an enclosing purlin 7, welding the reinforcing steel bar of the waist beam 14 on the jet grouting pile, then carrying out reinforcing steel bar binding according to design requirements, pouring concrete, connecting a shaft force meter 15 and a bracket in a welding mode, pre-assembling a steel pipe structure supporting beam by utilizing an automobile crane, a tower crane and a manual matching mode, connecting a first segment 5 and a second segment 11 through a connecting flange 4, stiff end 3 and loose joint end 6 are connected respectively at both ends, wait to enclose 7 concrete intensity of purlin and carry out steel tubular construction supporting beam installation work after reaching design strength 80%, stiff end 3 is connected with reinforced concrete bracket 2, loose joint end 6 is connected with enclosing purlin 7, the steel pipe supports and encloses the water repellent of 7 junctions of purlin, can demolish bearing structure also can need not demolish after the construction is accomplished, thereby make and face subway super large foundation ditch 12 and face the combined type supporting system forever and have improved work efficiency, the time limit for a project, construction cost and the effect of the displacement of strict restriction foundation ditch 12 have been reduced.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.