阅读说明：本技术 一种核心土开挖支护方法 (Core soil excavation supporting method ) 是由 张恒 康卫 李朝旭 彭鹏 韦云 何江 李云 项东东 黄则东 罗军 于 2021-10-08 设计创作，主要内容包括：本发明公开了一种核心土开挖支护方法,包括以下步骤：S1.核心土上部土体开挖及竖向临时支撑施工；S2.侧壁导坑开挖及支护；S3.拆除竖向临时支撑并开挖中、下部核心土。本发明提供的方法将核心土由弧形墙支护调整为直墙支护形式并优化施工步序,可降低核心土上部解除时的风险,使用上导坑开挖台架由上导坑侧面进行上部核心土的施工,便于挖机、装载机等大型机械作业。(The invention discloses a core soil excavation supporting method, which comprises the following steps: s1, excavating an upper soil body of core soil and constructing a vertical temporary support; s2, excavating and supporting a side wall guide pit; and S3, removing the vertical temporary supports and excavating the core soil at the middle and lower parts. According to the method provided by the invention, the core soil is adjusted to be in a straight wall support form from an arc wall support, the construction step is optimized, the risk of removing the upper part of the core soil can be reduced, the upper core soil is constructed from the side surface of the upper pilot tunnel by using the upper pilot tunnel excavation rack, and the operation of large machinery such as an excavator, a loader and the like is facilitated.)

1. A core soil excavation supporting method is characterized by comprising the following steps:

s1, excavating the upper soil body of the core soil and constructing vertical temporary supports;

s2, excavating and supporting a side wall pilot tunnel;

s3, removing the vertical temporary supports and excavating the core soil at the middle and lower parts;

wherein, the step S2 specifically includes:

s101, constructing upper core soil from the side surface, and immediately performing primary support after excavation is finished to close the primary support of the arch part;

and S102, excavating the upper part of the core soil, supporting and then applying reinforced vertical temporary support.

2. The core soil excavation support method of claim 1, wherein the vertical temporary supports include: the main support, the main support includes standard festival steel, nonstandard festival steel and telescoping device, standard festival steel, nonstandard festival steel and telescoping device are the columnar structure of the circular steel sheet of both ends welding, and circular steel sheet circumference is equipped with the several bolt hole, the telescoping device includes upper casing and lower casing, and the upper casing comprises two concentric sleeves, and the upper portion of lower casing inserts concentric sleeves and forms the relative slip with the upper casing within a definite time, the inside center of lower casing is equipped with the jack, standard festival steel, nonstandard festival steel and telescoping device's circular steel sheet passes through bolted connection.

3. The core soil excavation support method of claim 1, wherein the main supports are non-standard section steel, first standard section steel, second standard section steel and a telescopic device from top to bottom.

4. The core soil excavation support method of claim 1, wherein the step S102 is specifically: after excavation of the core soil at the upper part of the tunnel is finished, arranging a vertical temporary support below a tunnel vault which is 3m away from a tunnel face of the core soil at the upper part; after the installation is finished, the vertical temporary support is in close contact with the vault and the ground under the action of the hydraulic jack.

5. The core soil excavation support method of claim 3, wherein the vertical temporary supports are arranged at a single row spacing of 2 m.

6. The core soil excavation support method of claim 3, wherein the removed vertical reinforcing temporary supports are reused after the upper core soil is removed next time.

7. The core soil excavation support method of claim 1, wherein the step S3 is specifically: and removing the vertical temporary supports and excavating the middle and lower part core soil, and when the middle soil body of the core soil below the vertical reinforced temporary support position is removed, releasing the pressure of the jack to ensure that the vertical reinforced temporary supports do not play a role any more and removing the vertical reinforced temporary supports.

Technical Field

The invention relates to the field of excavation supporting, in particular to a core soil excavation supporting method.

Background

The urban rail transit construction is limited by complex environment, particularly in urban central areas with dense buildings and busy traffic, the construction of large-section underground excavated stations is inevitable, and from the construction method of the underground excavated stations of the built rock stratum rail transit, the double-side-wall pilot tunnel method is recommended by design units.

The biggest construction difficulty of the traditional double-side-wall pit guiding method for excavating the extra-large section tunnel lies in core soil construction in the later period, the excavation difficulty of the core soil at the upper part is large, the over-under excavation control is difficult, the turnover space of supporting operation materials is narrow and small, and the supporting operation materials are difficult to transfer by means of machinery.

Disclosure of Invention

Aiming at the problems, the invention provides a core soil excavation supporting method which is used for solving the problems that the biggest construction difficulty of excavation by a double-side-wall pit guiding method of an extra-large section tunnel is core soil construction in the later period, the excavation difficulty of the upper core soil is high, the control of over-short excavation is difficult, the turnover space of supporting operation materials is narrow, and the supporting operation materials are difficult to transfer by means of machinery.

The invention is realized by the following technical scheme:

a core soil excavation supporting method comprises the following steps:

s1, excavating an upper soil body of core soil and constructing a vertical temporary support;

s2, excavating and supporting a side wall guide pit;

s3, dismantling the vertical temporary supports and excavating the core soil at the middle and lower parts;

wherein, the step S2 specifically includes:

s101, constructing upper core soil from the side surface, and immediately performing primary support after excavation is finished to close the primary support of the arch part;

and S102, excavating the upper part of the core soil, supporting and then applying reinforced vertical temporary support.

Further, the vertical temporary support includes: the main support, the main support includes standard festival steel, nonstandard festival steel and telescoping device, standard festival steel, nonstandard festival steel and telescoping device are the columnar structure of the circular steel sheet of both ends welding, and circular steel sheet circumference is equipped with the several bolt hole, the telescoping device includes upper casing and lower casing, and the upper casing comprises two concentric sleeves, and the upper portion of lower casing inserts concentric sleeves and forms the relative slip with the upper casing within a definite time, the inside center of lower casing is equipped with the jack, standard festival steel, nonstandard festival steel and telescoping device's circular steel sheet passes through bolted connection.

Further, the main support is respectively a nonstandard section steel, a first standard section steel, a second standard section steel and a telescopic device from top to bottom.

Further, the step S102 specifically includes: after excavation of the core soil at the upper part of the tunnel is finished, vertical temporary supports are arranged below a tunnel vault which is 3m or so away from a tunnel face of the core soil at the upper part; after the installation is finished, the vertical temporary support is in close contact with the vault and the ground under the action of the hydraulic jack.

Further, the vertical temporary supports are arranged in a single row at a spacing of 2 meters.

Further, the vertical reinforcing temporary support after being dismantled is repeatedly used after the upper core soil is removed next time.

Further, the step S3 is specifically: and removing the vertical temporary supports and excavating the middle and lower part core soil, and when the middle soil body of the core soil below the vertical reinforced temporary support position is removed, releasing the pressure of the jack to ensure that the vertical reinforced temporary supports do not play a role any more and removing the vertical reinforced temporary supports.

The invention has the beneficial effects that: the biggest construction difficulty of the double-side-wall pit guiding method for excavating the extra-large section tunnel lies in core soil construction in the later period, the excavation difficulty of the core soil at the upper part is large, the over-under excavation control is difficult, the turnover space of supporting operation materials is narrow, and the supporting operation materials are difficult to transfer by means of machinery. According to the method provided by the invention, the core soil is adjusted to be in a straight wall support form from an arc wall support, the construction step is optimized, the risk of removing the upper part of the core soil can be reduced, the upper core soil is constructed from the side surface of the upper pilot tunnel by using the upper pilot tunnel excavation rack, and the operation of large machinery such as an excavator, a loader and the like is facilitated.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

FIG. 1 is a schematic flow chart of a method according to an embodiment of the present invention;

FIG. 2 is a three-dimensional perspective view of a vertical temporary support of an embodiment of the present invention;

FIG. 3 is a partial schematic view of a vertical temporary support of an embodiment of the present invention;

FIG. 4 is a partial schematic view of a vertical temporary support of an embodiment of the present invention;

FIG. 5 is a schematic illustration of a vertical temporary support according to an embodiment of the present invention in disassembled form;

FIG. 6 is a cross-sectional view of a vertical temporary support of an embodiment of the present invention;

in the figure: 1-first standard section steel, 2-second standard section steel, 3-non-standard section steel, 4-upper sleeve, 5-lower sleeve, 6-jack and 7-bolt hole.

Detailed Description

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 examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.

Example 1

As shown in fig. 1, this embodiment provides a core soil excavation supporting method, including the following steps:

s1, excavating an upper soil body of core soil and constructing a vertical temporary support;

s2, excavating and supporting a side wall guide pit;

s3, dismantling the vertical temporary supports and excavating the core soil at the middle and lower parts;

wherein, the step S2 specifically includes:

s101, constructing upper core soil from the side surface, and immediately performing primary support after excavation is finished to close the primary support of the arch part;

and S102, excavating the upper part of the core soil, supporting and then applying reinforced vertical temporary support.

Further, the vertical temporary support is shown in fig. 2, 3, 4, 5 and 6, and comprises: the main support, the main support includes standard festival steel, nonstandard festival steel 3 and telescoping device, standard festival steel, nonstandard festival steel 3 and telescoping device are the columnar structure of the circular steel sheet of both ends welding, circular steel sheet circumference is equipped with several bolt hole 7, the telescoping device includes upper casing 4 and lower casing 5, upper casing 4 comprises two concentric sleeves, the upper portion of lower casing 5 inserts concentric sleeves interchannel and upper casing 4 forms the relative slip, the inside center of lower casing 5 is equipped with jack 6, standard festival steel, nonstandard festival steel 3 and telescoping device's circular steel sheet passes through bolted connection.

Further, the main support is respectively provided with a nonstandard section steel 3, a first standard section steel 1, a second standard section steel 2 and a telescopic device from top to bottom.

Furthermore, the standard section steel, the non-standard section steel 3 and the round steel plate of the telescopic device are the same in size, and therefore assembly and use are facilitated.

Further, the axial length of the non-standard section steel 3 is smaller than that of the standard section steel.

Furthermore, the joint of the upper sleeve 4 and the lower sleeve 5 is provided with a limit buckle, so that the upper sleeve 4 and the lower sleeve 5 can be prevented from being separated when the upper sleeve and the lower sleeve stretch towards two ends to an overlarge extent.

Furthermore, the jack 6 is a large-tonnage jack, is firm and durable and has very good integrity.

Further, the main support has a cross-sectional sizeAnd t is 12 steel support.

Further, the main support is made of Q235 steel.

Further, the step S102 specifically includes: after excavation of the core soil at the upper part of the tunnel is finished, vertical temporary supports are arranged below a tunnel vault which is 3m or so away from a tunnel face of the core soil at the upper part; after the installation is finished, the vertical temporary support is in close contact with the vault and the ground under the action of the hydraulic jack.

Further, the vertical temporary supports are arranged in a single row at a spacing of 2 meters.

Further, the vertical reinforcing temporary support after being dismantled is repeatedly used after the upper core soil is removed next time.

Further, the step S3 is specifically: and removing the vertical temporary supports and excavating the middle and lower part core soil, and when the middle soil body of the core soil below the vertical reinforced temporary support position is removed, releasing the pressure of the jack to ensure that the vertical reinforced temporary supports do not play a role any more and removing the vertical reinforced temporary supports.

The vertical reinforcing temporary support mainly comprises a standard steel-saving support, a nonstandard steel-connecting 3 support and a telescopic device, wherein each part is connected by adopting a bolt, the two parts are the same and only have certain difference in axial length, two ends of the steel pipe are connected with a steel plate in a welding mode, bolt holes are uniformly designed for connecting the steel plate, and the bolt holes are reserved for bolt connection during the assembly of subsequent parts; the telescopic device mainly comprises an upper sleeve and a lower sleeve and a large-tonnage jack, wherein the upper sleeve 4 comprises two concentric sleeves, the upper part of the lower sleeve 5 is inserted between the two concentric sleeves and used for forming the up-down relative sliding of the upper sleeve 4 and the lower sleeve 5, and the large-tonnage jack is arranged in the center of the sleeves and used for adjusting the up-down stretching of the whole vertical temporary strengthening support.

Specifically, the vertical temporary support is installed in the following steps:

vertical enhancement supports each part temporarily and assembles after the processing factory preparation, reaches transport to the job site after the design requirement, lifts by crane each part to the tunnel entrance to a cave through the driving a vehicle, then transports the part to corresponding position, connects each part through the bolt, is nonstandard festival, standard festival and telescoping device respectively from last to down.

After excavation of the core soil at the upper part of the tunnel is finished, vertical reinforcing temporary supports are arranged below a tunnel vault which is 3m away from a tunnel face of the core soil at the upper part, rock masses at the installation positions are leveled as far as possible before the vertical reinforcing temporary supports are installed so as to be convenient to install, and the temporary vertical supports are arranged in a single row at intervals of 2 meters; after the installation is finished, the vertical reinforcing temporary support is in close contact with the vault and the ground under the action of the hydraulic jack, and the supporting effect of the vertical reinforcing temporary support is better exerted.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.