CN113668606B - Active control grouting lifting method for underground closed existing station - Google Patents

Active control grouting lifting method for underground closed existing station Download PDF

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Publication number
CN113668606B
CN113668606B CN202110950047.4A CN202110950047A CN113668606B CN 113668606 B CN113668606 B CN 113668606B CN 202110950047 A CN202110950047 A CN 202110950047A CN 113668606 B CN113668606 B CN 113668606B
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grouting
lifting
station
existing station
existing
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CN113668606A (en
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王海涛
许明杨
张志伟
刘国龙
尤强
张顶立
王忠昶
何历超
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Dalian Jiaotong University
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Dalian Jiaotong University
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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D29/00—Independent underground or underwater structures; Retaining walls
    • E02D29/045—Underground 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
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D15/00—Handling building or like materials for hydraulic engineering or foundations
    • E02D15/02—Handling of bulk concrete specially for foundation or hydraulic engineering purposes
    • E02D15/04—Placing concrete in mould-pipes, pile tubes, bore-holes or narrow shafts
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D29/00—Independent underground or underwater structures; Retaining walls
    • E02D29/04—Making large underground spaces, e.g. for underground plants, e.g. stations of underground railways; Construction or layout thereof
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D29/00—Independent underground or underwater structures; Retaining walls
    • E02D29/16—Arrangement or construction of joints in foundation structures
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D33/00—Testing foundations or foundation structures
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D2250/00—Production methods
    • E02D2250/0023—Cast, i.e. in situ or in a mold or other formwork

Abstract

The invention discloses an active control grouting lifting method for a subway station to closely stick and pass through an existing station. According to actual field data, a pilot tunnel position, the relative position of an existing station and a newly-built station, the position of a deformation joint of the existing station and a main influence area of close-fit underpass construction on the existing station, a grouting lifting scheme is compiled, deep hole grouting is adopted to form a grout stop wall, grouting is carried out by adopting a sleeve valve pipe after the grout stop wall is formed to lift the existing station, the grouting effect is checked after pilot tunnel excavation is finished, repeated grouting is carried out on parts with large individual settlement values, and settlement control is guaranteed to be within a controllable range. The method can actively control the settlement and deformation of the existing station when the newly built station is constructed by adopting a hole-pile method and the existing station is closely penetrated, so that the construction of the penetrating section is completed under the normal operation condition of the existing station, and the safety of the existing station and the closely penetrated construction is ensured.

Description

Active control grouting lifting method for underground railway station close-fitting underpass existing station
Technical Field
The invention belongs to the technical field of underground structure construction, and relates to an active control grouting lifting method for a subway station close-fitting underpass existing station, in particular to an active control grouting lifting method for a tunnel-pile method construction subway station close-fitting underpass existing station.
Background
In recent years, rail transit is developing towards three-dimensional, an underground three-dimensional intercommunication concept is established on the design concept of tunnels and underground engineering, and therefore projects with existing lines crossing from top to bottom are gradually increased. For the existing underground tunnel construction in a closed manner at home and abroad, the existing tunnel or the existing station construction and the existing station construction in the closed manner at the newly built station are mainly constructed in a closed manner, and the existing station construction in the closed manner at the newly built station is less. In order to facilitate the transfer between subway lines, more and more existing station projects can be closely worn under a newly built station. However, the construction risk of the close-fitting underpass of the station is high, the settlement control requirement of the existing station is high, the settlement requirement is generally controlled within 3mm, and the underpass section construction is guaranteed to be completed under the condition that the existing line normally operates, so that the control of the settlement of the existing line becomes the key point of the close-fitting underpass engineering construction.
Compared with the underpass construction of a newly-built tunnel, the structural section of the underpass construction of the newly-built station is obviously increased, and the current large-span underground excavation process mainly adopts a middle hole method and a cross intermediate wall method, but the settlement value caused by the two methods is larger. Compared with the two construction methods, the hole-pile method has better settlement control and good structural stress condition, and can be applied to the construction of existing stations which are closely attached and pass under subway stations. However, in spite of the construction by the hole pile method, the settlement value generated by the existing station still may exceed the control value in the construction process, and the construction is at great risk at the moment and has serious influence on the existing station. The main factors influencing the surface subsidence and the subsidence of the existing station are in the pilot tunnel excavation stage, and the subsidence caused by the pilot tunnel excavation stage can account for 40% -70% of the total construction subsidence.
Disclosure of Invention
In view of the above, the invention provides an active control grouting lifting method for a closed underpass existing station of a subway station constructed by a hole-pile method, so that the settlement of the existing station caused by closed underpass construction is actively controlled, the settlement of the existing station meets the requirement, and the construction safety is ensured.
The technical scheme of the invention is as follows:
an active control grouting lifting method for a subway station to closely pass through an existing station, wherein a newly-built station is constructed by adopting a hole-pile method to closely pass through the existing station, and when the settlement value of the existing station is close to an early warning value due to the close-fit downward-passing construction of the newly-built station, the grouting lifting method is used for providing active settlement control for the existing station, and comprises the following steps:
s1: construction preparation: before construction, according to actual site data, a pilot tunnel position, a relative position of an existing station and a newly-built station, a position of a deformation joint of the existing station and a main influence area of the close-fit underpass construction on the existing station, a grouting lifting scheme is compiled, staged grouting lifting is carried out according to a construction stage, a grouting lifting stage is arranged below the existing station between two adjacent deformation joints, and if the deformation joint exceeds the main influence area of the close-fit underpass construction, a grouting lifting stage is arranged below the existing station of the main influence area between the two adjacent deformation joints;
s2: arranging grouting holes: after the pilot tunnel at the first grouting lifting stage is excavated and communicated, grouting holes are arranged on the side walls (two side walls or single side wall) of the pilot tunnel;
s3: and (3) setting a grout stopping wall: a deep hole grouting process is adopted to construct a grout stop wall at the bottom and around the first grouting lifting stage, a closed space is formed in the first grouting lifting stage, grout is prevented from diffusing all around during grouting lifting, and the lifting effect is better achieved;
s4: grouting and lifting: after a grout stop wall is formed, grouting lifting is carried out at a first grouting lifting stage (grouting lifting is carried out on an existing station), a sleeve valve pipe grouting process capable of repeatedly grouting is adopted for grouting lifting, real-time encrypted monitoring is carried out on the existing station in the grouting process through settlement and differential settlement monitoring points which are distributed in the existing station in advance, monitoring data are analyzed in real time, field grouting work is guided according to the monitoring data, and related grouting parameters are adjusted in time;
s5: according to the grouting lifting step of the first grouting lifting stage, grouting lifting of the rest grouting lifting stages is carried out;
s6: and (3) grouting effect inspection: and after the grouting lifting and the pilot tunnel excavation are completed in each stage, analyzing whether the existing station has a large settlement part according to monitoring data, and if the settlement value of the individual part is large, performing repeated circulating grouting for many times, so as to ensure that the settlement is controlled within a controllable range, and provide favorable conditions for the construction of the next stage.
And the distance between the top plate of the newly built station and the bottom plate of the existing station is not more than 1 m.
Further, the arrangement of the grouting holes in the step S2 is several rows, and horizontal radial grouting is performed. The left-right spacing of the grouting holes is 0.8-1.2 m, the up-down spacing is 0.8-1.2 m, and the distance between the grouting holes of the bottom row and the primary support of the bottom plate of the pilot tunnel is 1 m. The deviation of the hole position is +/-3 cm, and the deviation of the incident angle is not more than 1 degree.
Further, in step S3, a grout stop wall is applied to the bottom of the first grouting lifting stage, then a grout stop wall is applied to the side portion (below the existing station side wall) of the first grouting lifting stage, and finally a grout stop wall is applied to the end portion (below the deformation joint or below the boundary of the main impact area of the close-fit underpass construction) of the first grouting lifting stage, so as to finally form a closed grouting area, that is, the first grouting lifting stage.
Furthermore, in the step S3, a grout stop wall is applied to the bottom of the first grouting lifting stage, and deep hole grouting is performed through the grouting holes in the bottom row. In the step S3, the side portion of the first grouting lifting stage is made into a grout stop wall, deep hole grouting is performed through the grouting holes on the left and right sides, and in the step S3, the end portion of the first grouting lifting stage is made into a grout stop wall, and deep hole grouting is performed through the remaining grouting holes.
The side part of the grouting lifting stage is a surface intersected with the pilot tunnel.
Further, when the slurry is lifted in the step S4: and grouting lifting is carried out by utilizing the bottom second row of grouting holes, after grouting is completed, if the monitoring result shows that the expected lifting effect (settlement lifting to the position near 0 mm) is achieved, the first grouting lifting stage is completed, and if the expected lifting effect is not achieved, grouting lifting is carried out by utilizing the bottom third row of grouting holes, so that circulation is realized. And after each row of grouting holes are subjected to grouting lifting, the expected lifting effect is not achieved or the existing station is settled at intervals, and then grouting is repeated from the second row of grouting holes at the bottom until the monitoring result shows that the expected lifting effect is achieved.
And grouting holes are arranged on two side walls or a single side wall of the pilot tunnel and are determined according to actual engineering.
Furthermore, grouting holes are arranged on two side walls of the pilot tunnel in step S2, when grouting is lifted in step S4, grouting lifting areas on two side walls of the pilot tunnel are divided into a plurality of areas along the direction of the pilot tunnel, synchronous grouting is performed on two sides of the pilot tunnel by adopting diagonal areas, grouting is performed on the outer side area first and then grouting is performed on the inner side area sequentially, grouting is performed symmetrically through the grouting holes in the same row, and a mode of grouting every two sides is adopted.
Furthermore, grouting holes are arranged on the single side wall of the pilot hole in step S2, when grouting is lifted in step S4, the grouting lifting area of the single side wall of the pilot hole is divided into a plurality of areas along the direction of the pilot hole, grouting is performed in the outer area first, then grouting is performed in the inner area sequentially, grouting is performed symmetrically in the same row of grouting holes, and a mode of grouting every other grouting is adopted.
Further, the grouting slurry is cement-water glass double-liquid slurry, and the double-liquid slurry comprises the following components in percentage by weight: 20-24% of water glass, 20-25% of cement and the balance of water. The concrete proportion of the grouting liquid can be finely adjusted according to the actual needs on site, and a proper amount of chemical admixture is added. The slurry must be stirred well before injection and it is often checked whether the setting time of the mixed slurry is suitable for the site working environment.
Further, the initial pressure of the grouting pressure is 0.5-0.8 MPa; the stable pressure is 1.5-2.0 MPa. When grouting is conducted on the grouting holes far away from the main construction influence area close to the deformation joint or between the deformation joints, the grouting pressure is properly increased according to monitoring data, and when grouting is conducted on the grouting holes close to the main construction influence area close to the deformation joint or between the deformation joints, the grouting pressure can be properly reduced, so that the existing line is prevented from being damaged.
Further, the grouting rate should be controlled within 24L/min, the balance between the diffusion rate of the slurry and the injection rate of the slurry is sought to be achieved, and when the grouting amount reaches the theoretical value (the maximum value is not more than 1.2 times of the theoretical value), the grouting should be stopped. And meanwhile, the flow and pressure changes of the slurry in the grouting process are observed in real time, if the flow or pressure suddenly increases or decreases, the slurry solidification time is adjusted in time, and the optimal slurry diffusion is realized. The grouting amount of a single hole is not required to be too large, and the grouting amount of the single hole is estimated according to the following formula: q ═ pi R2Ln alpha beta, wherein R is the diffusion radius of the slurry, and R is 0.6L0；L0The distance from the center to the center of the grouting hole; l is the hole length; n is the formation porosity; alpha is the stratum filling coefficient, and is generally 0.8; beta is the slurry consumption coefficient, and is generally 1.15.
Further, the grouting rate is monitored using a flow meter.
The beneficial results of the invention are:
(1) the active control of grouting lifting can effectively recover the existing station settlement caused by the close-fitting underpass construction;
(2) grouting and lifting are carried out by depending on the excavated pilot tunnel, the operation is simple, and grouting and lifting construction can be flexibly carried out according to the construction process;
(3) the grouting lifting is combined with the monitoring data to realize dynamic control lifting, so that the settlement deformation of the existing station is always in a controllable range;
(4) the method can be applied to the close-fitting underpass project of the future station.
Drawings
Fig. 1 is a flowchart of an active control grouting lifting method for a subway station close-proximity underneath-passing existing station constructed by a hole-pile method in the embodiment of the present invention.
Fig. 2 is a cross-sectional view of a first grouting lift stage of step S1 according to an embodiment of the invention.
Fig. 3 is a schematic diagram of the grouting lifting stage of step S1 in an embodiment of the invention.
Fig. 4 is a longitudinal sectional view of the arrangement of the injection holes of step S2 in an exemplary embodiment of the present invention.
Fig. 5 is a schematic view of the arrangement of monitoring points of step S4 in an embodiment of the present invention.
Description of reference numerals:
the device comprises a deformation joint 1, an existing station 2, a first grouting lifting stage 3, an upper layer first pilot tunnel 4, an upper layer second pilot tunnel 5, an upper layer third pilot tunnel 6, an upper layer fourth pilot tunnel 7, a fifth pilot tunnel 8, an existing station auxiliary structure channel 9, a vertical shaft 10, a transverse channel 11, an existing station structure settlement and difference settlement measuring point 12 and an existing station track structure settlement and difference settlement measuring point 13.
Detailed Description
For the convenience of understanding the technical solution of the present invention, the following description is further explained with reference to the accompanying drawings and specific examples, which are not to be construed as limiting the scope of the present invention.
Example 1
The newly-built subway station in the embodiment of the invention is constructed by adopting an eight-guide-hole pile method, and the distance between a top plate of the newly-built station and a bottom plate of the existing station is 0.5 m.
As shown in fig. 1, the active control grouting lifting method for constructing a subway station by a hole-pile method in the embodiment of the present invention, which is used for closely adhering an existing station passing through the subway station, includes the following steps:
s1: construction preparation: according to actual on-site data, a pilot tunnel position, the relative position of an existing station and a newly-built station, the position of an existing station deformation joint and the main influence area of close-up underpass construction on the existing station before construction, a grouting lifting scheme is compiled, the grouting lifting scheme comprises the step of lifting three grouting lifting structures, the first grouting lifting structure is arranged between the adjacent deformation joints 1 of the existing station 2 on the south and north sides of the upper first pilot tunnel 4, and the first grouting lifting stage is arranged below the existing station 2 structure between the adjacent deformation joints 1 of the existing station 2 on the south and north sides of the upper first pilot tunnel 4. The second grouting lifting structure is an existing station 2 structure which is greatly influenced by the underpass construction between deformation joints 1 of existing stations 2 on the north and south sides of an upper layer of fourth guide hole 7, and a second grouting lifting stage is arranged below the existing station 2 structure between the boundaries of main underpass construction influence areas, wherein the deformation joints 1 on the north side of the upper layer of fourth guide hole 7 and the south side of the fourth guide hole 7 are closely attached to the underpass construction. The third slip casting lifting structure is an existing station auxiliary structure channel 9 and is divided into an east area and a west area, a third slip casting lifting stage is arranged below the existing station auxiliary structure channel 9 between adjacent deformation joints 1 of the east area, and a fourth slip casting lifting stage is arranged below the deformation joint 1 of the west area and the existing station auxiliary structure channel 9 between the close-fit underpass construction main influence area boundaries. Taking the first pilot tunnel 4 as an example, the schematic cross-sectional view of the first grouting lifting stage is shown in fig. 2, and the schematic cross-sectional view of the four grouting lifting stages is shown in fig. 3, and the grouting lifting is performed in stages according to the construction stage.
S2: construction in a first grouting lifting stage:
arranging grouting holes: three rows of grouting holes (as shown in fig. 4) are respectively arranged on the two side walls of the upper-layer first pilot tunnel 4 excavated to penetrate through the first grouting lifting stage, and horizontal radial grouting is performed. The left-right distance of the grouting holes is 0.9m, the up-down distance of the grouting holes is 0.8m, and the distance between the lowest row of grouting holes and the primary support of the bottom plate of the pilot tunnel is 1 m. The deviation of the grouting holes is +/-3 cm, and the deviation of the incident angle is not more than 1 degree;
and (3) setting a grout stopping wall: before lifting grouting, a deep hole grouting process is adopted to construct a grout stop wall at the bottom and around the first grouting lifting stage, the thickness of the grout stop wall is 1m, a closed space is formed in the first grouting lifting stage, grout is prevented from diffusing around during lifting grouting, and the lifting effect is better achieved; the method specifically comprises the following steps: firstly, a grout stop wall is applied to the bottom of the first grouting lifting stage, then a grout stop wall is applied to the side part (below the side wall of the existing station) of the first grouting lifting stage, and finally a grout stop wall is applied to the end part (below the adjacent deformation joint 1 of the station 2 at the north and south sides of the upper first guide hole 4) of the first grouting lifting stage to finally form a closed grouting area, namely the first grouting lifting stage;
grouting and lifting: and grouting and lifting are carried out on the first grouting and lifting stage (the existing station 2 structure) after the grout stop wall is formed, and the grouting and lifting adopt a sleeve valve pipe grouting process capable of repeatedly grouting. During grouting lifting, grouting lifting areas on two sides of the upper first pilot tunnel 4 are divided into four areas along the direction of the upper first pilot tunnel 4, synchronous grouting is carried out on diagonal areas, grouting is carried out on the outer side area first and then grouting is carried out on the inner side area sequentially, grouting is carried out symmetrically on grouting holes in the same row, a mode of one-by-one grouting is adopted, grouting lifting is carried out by utilizing the grouting holes in the middle row first, after grouting is finished, monitoring is carried out through the existing station structure settlement and differential settlement monitoring points 12 and the existing station track structure settlement and differential settlement measuring points 13 which are distributed in the existing station in advance, if the monitoring result shows that the expected lifting effect (settlement lifting is up to the vicinity of 0 mm), the first grouting lifting stage 3 is finished, and if the expected lifting effect is not achieved, grouting lifting is carried out by utilizing the grouting holes in the top row. And after each row of grouting holes are subjected to grouting lifting, the expected lifting effect is not achieved or the existing station is settled at intervals, and then grouting is repeated from the middle row of grouting holes until the monitoring result shows that the expected lifting effect is achieved.
And S3 construction at the second grouting lifting stage:
arranging grouting holes: and three rows of grouting holes are respectively arranged on the side walls of the two sides of the upper layer fourth pilot tunnel 7 which is excavated to penetrate through the second grouting lifting stage, and horizontal radial grouting is performed. The left-right distance of the grouting holes is 0.9m, the up-down distance of the grouting holes is 0.8m, and the distance between the lowest row of grouting holes and the primary support of the bottom plate of the pilot tunnel is 1 m. The deviation of the grouting holes is +/-3 cm, and the deviation of the incident angle is not more than 1 degree;
and (3) setting a grout stopping wall: before lifting grouting, a deep hole grouting process is adopted to construct a grout stop wall at the bottom and around the second grouting lifting stage, the thickness of the grout stop wall is 1m, a closed space is formed in the second grouting lifting stage, grout cannot be diffused all around during lifting grouting, and the lifting effect is better achieved; the method specifically comprises the following steps: and (3) constructing a grout stop wall at the bottom of the second grouting lifting stage, constructing grout stop walls at the side parts (below the side wall of the existing station 2) of the second grouting lifting stage, and constructing grout stop walls at the end parts (below the north deformation joint 1 of the fourth guide hole 7 and below the boundary of the main penetration construction influence area closely adhered to the south side of the fourth guide hole 7) of the second grouting lifting stage to finally form a closed grouting area, namely the second grouting lifting stage.
Grouting and lifting: and grouting and lifting are carried out on the second grouting and lifting stage (the existing station 2 structure) after the grout stop wall is formed, and the grouting and lifting adopt a sleeve valve pipe grouting process capable of repeatedly grouting. During grouting lifting, grouting lifting areas on two sides of the upper-layer fourth pilot tunnel 7 are divided into four areas along the direction of the upper-layer fourth pilot tunnel 7, synchronous grouting is performed on diagonal areas, grouting is performed on the outer side area first and then grouting is performed on the inner side area sequentially, grouting is performed symmetrically on the same-row grouting holes, a mode of one-by-one grouting is adopted, grouting lifting is performed by using the middle-row grouting holes first, after grouting is completed, monitoring is performed through the existing station structure settlement and differential settlement monitoring points 12 and the existing station track structure settlement and differential settlement measuring points 13 which are distributed in the existing station in advance, if the monitoring result shows that the predicted lifting effect is achieved, the second grouting lifting stage is completed, and if the predicted lifting effect is not achieved, grouting lifting is performed by using the top-row grouting holes. After each row of grouting holes are subjected to grouting lifting, the expected lifting effect is not achieved or the station is settled at intervals, and then grouting is repeatedly performed from the middle row of grouting holes until the monitoring result shows that the expected lifting effect is achieved;
s4 construction in the third grouting lifting stage:
arranging grouting holes: after the upper layer fourth pilot hole 7 and the fifth pilot hole 8 are communicated with each other, three rows of grouting holes are respectively arranged on the side walls of the two sides of the upper layer fourth pilot hole 7, and horizontal radial grouting is carried out. The left-right distance of the grouting holes is 0.9m, the up-down distance of the grouting holes is 0.8m, and the distance between the lowest row of grouting holes and the primary support of the bottom plate of the pilot tunnel is 1 m. The deviation of the grouting holes is +/-3 cm, and the deviation of the incident angle is not more than 1 degree;
and (3) setting a grout stopping wall: before lifting grouting, a deep hole grouting process is adopted to construct a grout stop wall at the bottom and around the third grouting lifting stage, the thickness of the grout stop wall is 1m, a closed space is formed in the third grouting lifting stage, grout is prevented from diffusing around during lifting grouting, and the lifting effect is better achieved; the method specifically comprises the following steps: the method comprises the following steps of firstly constructing a grout stop wall at the bottom of a third grouting lifting stage, then constructing a grout stop wall at the side part (below a deformation joint 1 in the east region of an existing station auxiliary structure channel 9) of the third grouting lifting stage, and finally constructing a grout stop wall at the end part (below a channel side wall) of the third grouting lifting stage to finally form a closed grouting region, namely the third grouting lifting stage.
Grouting and lifting: and (3) grouting and lifting the third grouting and lifting stage (the existing station auxiliary structure channel 9) after the grout stop wall is formed, wherein the grouting and lifting adopts a sleeve valve pipe grouting process capable of repeatedly grouting. During grouting lifting, grouting lifting areas on two sides of the upper-layer fourth pilot tunnel 7 are divided into two areas along the direction of the upper-layer fourth pilot tunnel 7, synchronous grouting is performed on diagonal areas, grouting is performed on the outer side area first and then grouting is performed on the inner side area sequentially, grouting is performed symmetrically on the same-row grouting holes, a mode of one-by-one grouting is adopted, grouting lifting is performed by using the middle-row grouting holes first, after grouting is completed, monitoring is performed through the existing station structure settlement and differential settlement monitoring points 12 and the existing station track structure settlement and differential settlement measuring points 13 which are pre-arranged on the existing station, if the monitoring result shows that the predicted lifting effect is achieved, the third grouting lifting stage is completed, and if the predicted lifting effect is not achieved, grouting lifting is performed by using the top-row grouting holes. After each row of grouting holes are subjected to grouting lifting, the expected lifting effect is not achieved or the station is settled at intervals, and then grouting is repeatedly performed from the middle row of grouting holes until the monitoring result shows that the expected lifting effect is achieved;
s5 construction at the fourth grouting lifting stage:
arranging grouting holes: after the upper layer fourth pilot hole 7 and the fifth pilot hole 8 are communicated with each other, three rows of grouting holes are arranged on the south side walls of the upper layer fourth pilot hole 7 and the fifth pilot hole 8, and horizontal radial grouting is performed. The left-right distance of the grouting holes is 0.9m, the up-down distance of the grouting holes is 0.8m, and the distance between the lowest row of grouting holes and the primary support of the bottom plate of the pilot tunnel is 1 m. The deviation of the grouting holes is +/-3 cm, and the deviation of the incident angle is not more than 1 degree;
and (3) setting a grout stopping wall: before lifting grouting, a deep hole grouting process is adopted to construct a grout stop wall at the bottom and around the fourth grouting lifting stage, the thickness of the grout stop wall is 1m, a closed space is formed in the fourth grouting lifting stage, grout is prevented from diffusing around during lifting grouting, and the lifting effect is better achieved; the method specifically comprises the following steps: the method comprises the following steps of constructing a grout stop wall at the bottom of a fourth grouting lifting stage, constructing a grout stop wall at the side part (a deformation joint 1 in the west area of an existing station auxiliary structure passage 9 and below the boundary of a main influence area of close-fit underpass construction) of the fourth grouting lifting stage, and constructing a grout stop wall at the end part (below a passage side wall) of the fourth grouting lifting stage to finally form a closed grouting area, namely the fourth grouting lifting stage.
Grouting and lifting: and (3) grouting and lifting the fourth grouting and lifting stage (the existing station auxiliary structure channel 9) after the grout stop wall is formed, wherein the grouting and lifting adopts a sleeve valve pipe grouting process capable of repeatedly grouting. During grouting lifting, a fourth grouting lifting stage grouting lifting area is divided into three areas along the directions of an upper layer fourth pilot tunnel 7 and a fifth pilot tunnel 8, grouting is performed on two side areas firstly, grouting is performed on a middle area, grouting is performed symmetrically on the same row of grouting holes, a mode of one-in-one grouting is adopted, grouting lifting is performed by using the middle row of grouting holes firstly, after grouting is completed, monitoring is performed through an existing station structure settlement and differential settlement monitoring point 12 and an existing station track structure settlement and differential settlement measuring point 13 which are pre-arranged on an existing station, if a monitoring result shows that a predicted lifting effect is achieved, the fourth grouting lifting stage is completed, and if the predicted lifting effect is not achieved, grouting lifting is performed by using top row grouting holes. After each row of grouting holes are subjected to grouting lifting, the expected lifting effect is not achieved or the station is settled at intervals, and then grouting is repeatedly performed from the middle row of grouting holes until the monitoring result shows that the expected lifting effect is achieved;
s6: and (3) grouting effect inspection: after the grouting lifting and the pilot tunnel excavation are completed in the four stages, whether a large settlement part exists in the existing station or not is analyzed according to monitoring data, if the settlement value of the specific part is large, repeated circulating grouting is performed for many times, the settlement is controlled within a controllable range, and favorable conditions are provided for the construction of the next stage.
The grouting slurry is cement-water glass double-liquid slurry, and the components of the double-liquid slurry comprise the following components in percentage by weight: 24% of water glass, 25% of cement and the balance of water. The concrete proportion of the grouting liquid can be finely adjusted according to the actual needs on site, and a proper amount of chemical admixture is added. The slurry must be stirred well before injection and it is often checked whether the setting time of the mixed slurry is suitable for the site working environment. In order to protect the safety of the existing station, grouting is carried out during groutingThe pressure is not suitable to be too large, the grouting rate is not suitable to be too fast, and the grouting amount (single hole) is not suitable to be too large. The initial pressure of the grouting pressure is 0.5-0.8 MPa; the stable pressure is 1.5-2.0 MPa. The bottom row grouting holes can increase the grouting pressure properly according to monitoring data, and the middle row grouting holes and the top row grouting holes can reduce the grouting pressure properly during grouting, so that the existing line is prevented from being damaged. And monitoring the grouting rate by using a flowmeter, and controlling the grouting rate within 24L/min so as to achieve the balance between the diffusion rate of the slurry and the injection rate of the slurry. When the grouting amount reaches the theoretical value (the maximum is not more than 1.2 times of the theoretical value), grouting should be stopped. Meanwhile, the flow and pressure changes of the slurry in the grouting process are observed in real time, if the flow or pressure suddenly increases or decreases, the slurry solidification time is adjusted in time, and the optimal slurry diffusion is achieved. The grouting amount of the single hole is estimated according to the following formula: q ═ pi R2Ln alpha beta, wherein R is the diffusion radius of the slurry, and R is 0.6L0；L0The distance from the center to the center of the grouting hole; l is the hole length; n is the formation porosity; alpha is the stratum filling coefficient, and is generally 0.8; beta is the slurry consumption coefficient, and is generally 1.15.

Claims (8)

1. The active control grouting lifting method for the subway station to closely pass through the existing station is characterized by comprising the following steps of: the newly-built station adopts a hole-pile method to construct a close-fit underneath-pass existing station, and the grouting lifting method comprises the following steps:
s1: construction preparation: before construction, according to actual site data, a pilot tunnel position, a relative position of an existing station and a newly-built station, a position of a deformation joint of the existing station and a main influence area of the close-fit underpass construction on the existing station, a grouting lifting scheme is compiled, staged grouting lifting is carried out according to a construction stage, a grouting lifting stage is arranged below the existing station between two adjacent deformation joints, and if the deformation joint exceeds the main influence area of the close-fit underpass construction, a grouting lifting stage is arranged below the existing station in the main influence area between the two adjacent deformation joints;
s2: arranging grouting holes: after the pilot tunnel at the first grouting lifting stage is excavated and communicated, grouting holes are arranged on the side wall of the pilot tunnel; three rows of grouting holes are formed, and horizontal radial grouting is performed;
s3: and (3) setting a grout stopping wall: constructing a grout stop wall at the bottom and around the first grouting lifting stage by adopting a deep hole grouting process, and forming a closed space in the first grouting lifting stage;
s4: grouting and lifting: after the grout stop wall is formed, grouting lifting is carried out at a first grouting lifting stage, grouting lifting adopts a sleeve valve pipe grouting process capable of repeatedly grouting, settlement and differential settlement monitoring points which are distributed at an existing station in advance are used for carrying out real-time encryption monitoring on the existing station in the grouting process, monitoring data are analyzed in real time, field grouting work is guided according to the monitoring data, and related grouting parameters are adjusted in time; firstly, grouting and lifting are carried out by utilizing a middle-row grouting hole, after grouting is finished, monitoring is carried out through an existing station structure settlement and differential settlement monitoring point and an existing station track structure settlement and differential settlement measuring point which are pre-arranged on an existing station, if a monitoring result shows that a predicted lifting effect is achieved, a first grouting and lifting stage is finished, and if the predicted lifting effect is not achieved, grouting and lifting are carried out by utilizing a top-row grouting hole; after each row of grouting holes are subjected to grouting lifting, the expected lifting effect is not achieved or the station is settled at intervals, and then grouting is repeatedly performed from the middle row of grouting holes again until the monitoring result shows that the expected lifting effect is achieved;
s5: according to the grouting lifting step of the first grouting lifting stage, grouting lifting of the rest grouting lifting stages is carried out;
s6: and (3) grouting effect inspection: and after the grouting lifting and the pilot tunnel excavation are completed in each stage, analyzing whether the existing station has a large settlement part according to monitoring data, and if the settlement value of the individual part is large, performing repeated circulating grouting for many times, so as to ensure that the settlement is controlled within a controllable range, and provide favorable conditions for the construction of the next stage.
2. The active control grouting lifting method for the subway station to pass through the existing station under the close contact of the subway station as claimed in claim 1, characterized in that: and the distance between the top plate of the newly built station and the bottom plate of the existing station is not more than 1 m.
3. The active control grouting lifting method for the subway station to closely pass through the existing station as claimed in claim 1, wherein: in step S3, a grout stop wall is first formed at the bottom of the first grouting lifting stage, then a grout stop wall is formed at the side of the first grouting lifting stage, and finally a grout stop wall is formed at the end of the first grouting lifting stage, so as to finally form a closed grouting area, i.e., the first grouting lifting stage.
4. The active control grouting lifting method for the subway station to pass through the existing station under the close contact of the subway station as claimed in claim 1 or 3, characterized in that: and step S2, arranging grouting holes on two side walls of the pilot tunnel, dividing grouting lifting areas of the two side walls of the pilot tunnel into a plurality of areas along the direction of the pilot tunnel when grouting is lifted in the step S4, synchronously grouting diagonal areas on two sides of the pilot tunnel, sequentially grouting the outer areas and then grouting the inner areas, symmetrically grouting the grouting holes in the same row, and performing alternate grouting.
5. The active control grouting lifting method for the underground existing station with the close contact of the subway station as claimed in claim 1 or 3, characterized in that: and step S2, arranging grouting holes on the single side wall of the pilot hole, dividing the grouting lifting area of the single side wall of the pilot hole into a plurality of areas along the direction of the pilot hole when grouting is lifted in step S4, grouting the outer area first and then sequentially grouting the inner area, symmetrically grouting the same row of grouting holes, and adopting a mode of grouting every other row.
6. The active control grouting lifting method for the subway station to closely pass through the existing station as claimed in claim 1, wherein: the initial pressure of the grouting pressure is 0.5-0.8 MPa; the stable pressure is 1.5-2.0 MPa.
7. The active control grouting lifting method for the subway station to closely pass through the existing station as claimed in claim 1, wherein: the grouting rate was monitored using a flow meter.
8. The active control grouting lifting method for the subway station to closely pass through the existing station as claimed in claim 1, wherein: the grouting slurry is cement-water glass double-liquid slurry, and the components of the double-liquid slurry comprise the following components in percentage by weight: 20-24% of water glass, 20-25% of cement and the balance of water.
CN202110950047.4A 2021-01-15 2021-08-18 Active control grouting lifting method for underground closed existing station Active CN113668606B (en)

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