CN116201172A

CN116201172A - Active control method for existing underground structure of ultra-small clear distance long-distance oblique crossing rail transit

Info

Publication number: CN116201172A
Application number: CN202310259602.8A
Authority: CN
Inventors: 王臣; 张志伟; 庄建杰; 马亮; 李泽慧; 王翠利; 王蕊秀
Original assignee: Beijing Urban Construction Design and Development Group Co Ltd
Current assignee: Beijing Urban Construction Design and Development Group Co Ltd
Priority date: 2023-03-17
Filing date: 2023-03-17
Publication date: 2023-06-02

Abstract

An active control method for an existing underground structure of ultra-small-clear-distance long-distance oblique crossing rail transit comprises the following steps: step one: collecting archival data of an underground structure of the operation rail transit; step two: detecting the current situation of the existing track traffic structure and the track structure, and determining a structure continuous deformation control value W; step three: determining an active lifting structure system of an existing operation rail transit underground structure; step four: determining an active lifting structure system, wherein the lifting structure is divided into a vertical lifting structure and a horizontal lifting structure; step five: performing construction of a newly built rail transit structure to pass through the existing operation rail transit structure; therefore, the invention realizes the sedimentation control effect which cannot be achieved by other crossing methods, thereby ensuring the operation safety of the existing operation rail transit line during crossing construction, and simultaneously has simple and convenient operation, controllable manufacturing cost and construction period.

Description

Active control method for existing underground structure of ultra-small clear distance long-distance oblique crossing rail transit

Technical Field

The invention relates to the technical field of underground rail transit construction, in particular to an active control method for an existing underground structure of ultra-small-net-distance long-distance oblique crossing rail transit.

Background

Along with the acceleration of urban process in China, rail transit is being planned and built in a large quantity in China, and the method has the characteristics of land conservation, rapidness, punctuality and environmental protection. However, compared with other urban infrastructures, the urban infrastructure has higher requirements on operation safety, and once the urban infrastructure is built around the urban infrastructure, other building structures are required to be built, so that the problems of high construction risk, long construction period and high investment are often caused.

However, from the viewpoint of urban planning and development, many projects need to be built adjacent to or crossing the urban rail transit projects in operation, in this case, the feasibility of the projects is often to be researched and judged, and because the construction method and experience for crossing the underground structure of the urban rail transit operation are deficient, many projects abandon crossing the urban rail transit, so that the construction quality of new projects is greatly compromised, and even part of projects stop or abandon construction is caused, so that the urban planning and construction level is influenced, and the overall competitiveness of the urban in China is restricted.

Underground structures and geotechnical engineers have developed, practiced and explored a great deal in recent years, and have made great progress in methods and techniques for traversing operational rail transit underground structures in comparison with those of the previous years. But the whole condition at the present stage is as follows:

1. the existing traversing method is mainly concentrated in vertical traversing (the newly built structure and the existing rail traffic structure are traversed under the condition of approaching to 90 degrees), relatively more research results are obtained in comparison with the early stage, and more vertical traversing engineering construction is lifted.

2. A small amount of research results are obtained on long-distance oblique crossing of a large clear distance (generally, the large clear distance refers to the excavation hole diameter of which the excavation clear distance is larger than one time), and a small amount of successful construction cases exist, but the whole is still in a fumbling stage.

3. The core reason of the method is that no successful construction is found in the case of passing through an ultra-small clear distance (the ultra-small clear distance refers to the excavation hole diameter of which the excavation clear distance is smaller than one time and comprises the condition that the clear distance is zero), and long-distance oblique crossing (the long-distance oblique crossing refers to the condition that a new structure and an existing rail traffic structure pass through under the condition that the angle is smaller than 30 degrees).

The ultra-small clear distance long-distance oblique crossing is difficult to realize in the current engineering world, the core technical difficulty is deformation control, and the deformation control value allowed by the underground structure of the running rail transit of Beijing is 3mm sedimentation and 2mm bulge. Taking a newly-built rail transit underground structure which is easy to realize as an example of a vertically-crossing operation rail transit underground structure, the single-line linear meter soil body excavation area of crossing engineering is usually 35-50 square meters, and the soil body excavation volume is 350-500 m ³ In such a case of large excavation, it is conceivable to achieve a deformation control difficulty in the millimeter level. However, if the deformation control value cannot be met, the problems of structural damage, track deformation and driving safety influence are caused, and the track traffic has the characteristic of large traffic and carries a plurality of passengers, so that the consequences of the driving safety problem are not considered once.

On the basis of the characteristics of ultra-small clear distance long-distance oblique crossing, the method has the characteristics of long crossing time, large excavation volume and short distance. It is well known that the environmental deformation caused by the excavation of an underground project (the deformation of the soil body in the excavation influence area of a new project and all underground structures including running rail traffic, which is generated during the excavation of a new project) is related to the excavation time, the excavation soil body square quantity and the clear distance. According to experience in the field of underground engineering construction, the longer the excavation time is, the larger the excavation soil body square quantity is, the smaller the vertical clearance is, and the larger the environmental deformation is caused. Under the condition of long-distance small-intersection crossing, the excavation time can reach more than 5-10 times of the vertical crossing excavation time, and the soil excavation volume can reach 2450-3500 m ³ (equivalent to 6-layer house)The body quantity of 2 units of the civil building) is more than that, and meanwhile, the free distance is ultra-small and has no sedimentation buffer space, so that the sedimentation deformation of the civil building is difficult to meet the operation safety requirement.

In the three-period planning of Beijing metro, the situation that partial engineering is required to cross the existing operation line in ultra-small clear distance and long distance due to the limitation of objective construction conditions occurs, and the feasibility of engineering construction is difficult to judge under the influence of the existing line crossing technology. Thus restricting the implementation of high-quality landing of Beijing city planning. The method is a method for crossing the existing line of the rail transit without ultra-small clear distance and long distance.

Therefore, the determiner of the invention has the advantages of solving the above-mentioned drawbacks, combining the experience and results of related industries for many years through intensive research and determination, and researching and determining an active control method of the existing underground structure of ultra-small clear distance long-distance oblique crossing rail transit so as to overcome the above-mentioned drawbacks.

Disclosure of Invention

The invention aims to provide an active control method for an existing underground structure of ultra-small clear distance long-distance oblique crossing rail transit, which solves the problem that the construction method for the existing underground structure of the traditional crossing rail transit cannot realize ultra-small clear distance long-distance oblique crossing of an existing operation line. Meanwhile, the method is provided with a clear and controllable active control system, so that active control of existing wire deformation can be realized.

In order to achieve the above purpose, the invention discloses an active control method for the existing underground structure of the ultra-small clear distance long-distance oblique crossing rail transit, which is characterized by comprising the following steps:

step one: collecting archival data of an underground structure of the operation track traffic, and simultaneously performing on-site investigation to determine the plane and vertical position of the underground structure of the existing operation track traffic, geomechanical parameters of stratum, geometric dimension information of the existing track traffic structure and related information of the track structure;

step two: the existing track traffic structure and the track structure are subjected to current situation detection, the current situation mechanical properties of the existing track traffic structure and the track structure are evaluated, the capability of the existing track traffic structure for continuous deformation is judged according to the information of crack development degree, carbonization degree and steel bar corrosion degree, and after the structure is continuously deformed, a structure continuous deformation control value W is determined;

step three: after the structure continuous deformation control value W of the existing operation track traffic underground structure is determined, determining an active lifting structure system of the existing operation track traffic underground structure, wherein the active lifting structure system is used for ensuring the safe use of existing line traveling crane when a new construction project passes through the operation track traffic underground structure and bears the loads of soil load, ballast bed load, track load, vehicle load and all relevant civil engineering and equipment facilities in a track extending area above the existing operation track traffic underground structure, and comprises determining a lifting point position of the structure;

step four: after the lifting point positions are determined, determining an active lifting structure system, wherein the active lifting structure system consists of an existing operation rail transit underground structure and a lifting structure, the lifting structure is divided into a vertical lifting structure and a transverse lifting structure, the vertical lifting structure is arranged at the lifting point positions, and the transverse lifting structure is arranged at the upper part of the vertical lifting structure;

step five: after the active lifting structure system is determined to be finished, construction that the newly built rail transit structure passes through the existing operation rail transit structure is carried out.

Wherein: the structure continuous deformation control value W takes one of the minimum value of a deformation limit value W1 corresponding to the bearing capacity, a deformation limit value W2 corresponding to the deformation of the structural member, a deformation limit value W3 corresponding to the existing structural crack and a deformation limit value W4 corresponding to the train running safety.

Wherein: the deformation limit value W1 corresponding to the bearing capacity is analyzed by establishing a load structure model through finite element software, the deformation of the structure in the crossing process is simulated, and under the deformation effect, when any one of bending moment, shearing force and axial force generated in the operated structure and the track is about to exceed the limit, the corresponding deformation value is the deformation limit value W1 corresponding to the bearing capacity;

the deformation limit value W2 corresponding to the deformation limit value of the structural member is analyzed by establishing a load structural model through finite element software, the deformation of the structural member in the crossing process is simulated in the analysis, the deformation of each beam, plate and column of the structure under the deformation is statistically recorded, the statistical recording result is compared with the deformation limit value of the structural member in the original determined drawing, and the deformation limit value corresponding to the deformation limit value of the structural member in the original determined drawing is W2;

the deformation limit W3 corresponding to the durability is analyzed by establishing a load structure model through finite element software, the deformation of the structure in the crossing process is simulated in the analysis, the crack value of the component of each beam, plate and column of the structure under the deformation is calculated, the statistical record result is compared with the crack limit in the original determined drawing, and the deformation limit corresponding to the crack limit of the component of each beam, plate and column of the structure, which is reached by any crack in the component in the original determined drawing, is W3;

the deformation limit value W4 of the train running safety requirement is performed by analyzing the rail deformation allowable value, and the rail deformation allowable value is directly equal to W4 because the rail is closely attached to the structure.

Wherein: the lifting point position determination should consider the influence of subsequent lifting structure construction on the safety of the existing operation track traffic line, avoid too close facilities of distance operation track traffic vehicles, contact networks and cables during construction, influence the existing line operation safety, and simultaneously, the lifting point position determination should reduce the damage of subsequent newly built structure engineering construction on the lifting structure.

Wherein: the vertical lifting structure should consider the influence of construction on the operation safety of the existing line, and mainly consider the influence of standing of construction machinery and construction on operation trains and operation equipment, and construction safety isolation measures should be set.

Wherein: the width of the components of the transverse lifting structure is checked by partial pressure according to P1, P2 and P3 … … after loading all vertical loads P1, P2 and P3 … … of the area served by each lifting structure, and the width required by the transverse lifting structure is obtained under the condition of ensuring that the bearing capacity and durability index of the existing rail transit structure are not exceeded.

Wherein: and not less than 2 hydraulic jacks are arranged in each transverse lifting structure.

Wherein: step five, the following implementation steps are included;

step 5.1: a vertical lifting structure is arranged at the position of the fixed lifting point, a small manually-operated vertical shaft is adopted in the vertical lifting structure, a mode of vertical steel grids and a sprayed concrete structure is adopted for supporting during the excavation of the vertical lifting structure, and a steel pile casing is arranged in the vertical lifting structure to be chiseled off in the later period;

step 5.2: a transverse lifting structure is arranged in the vertical lifting structure, a steel grating and shotcrete U-shaped structure is adopted for a side wall and a bottom plate of a primary support of the transverse lifting structure, after the primary support of the transverse lifting structure is closed, a transverse reinforcement cage of a lower stress system is placed in the transverse reinforcement cage, an embedded hydraulic jack fixing support is arranged above the transverse reinforcement cage, a reserved movable steel mounting position is arranged above the embedded hydraulic jack fixing support, a movable steel structure is mounted, and a hydraulic jack is arranged at the position of the embedded hydraulic jack fixing support;

step 5.3: the mutual anchor reinforcement cage is applied in the vertical lifting structure, the mutual anchor reinforcement cage, the reinforcement anchored by the transverse reinforcement cage in the transverse lifting structure and the internal beard reinforcement of the all-steel pile casing form a reinforcement mutual anchoring structure together, after the application is finished, concrete is poured to form an integral vertical lifting structure to the base position of the transverse lifting hydraulic jack, and an active lifting structure system is formed;

step 5.4: constructing an advanced support of a newly built rail transit structure, and constructing an initial support of the newly built structure, wherein the construction adopts an equal-step method of ascending and descending steps;

step 5.5: during the excavation of a newly built rail transit structure, carrying out settlement monitoring in real time;

step 5.6: grouting soil under the existing line at low pressure through a grouting pipe;

step 5.7: continuing construction until the newly built waterproof and permanent structure is completed;

step 5.8: in the area where the hydraulic jack is arranged, a structure for supporting the section steel to lift the steel gasket is used for replacing the hydraulic jack;

step 5.9: and pouring vertical shaft concrete of the vertical lifting structure to form a plain concrete structure to the natural ground, so as to complete all the construction.

Wherein: and 5.8, firstly adding supporting section steel to lift the steel gasket, unloading the hydraulic jack after the steel gasket is firmly lifted, and taking out the hydraulic jack.

Wherein: and taking out the wires in sections according to the monitoring result so as to ensure the safety of existing wire sedimentation control.

From the above, the active control method for the ultra-small clear distance long-distance oblique crossing track traffic existing underground structure has the following effects:

1. the deformation control system is composed of two core systems and an auxiliary system. The first core system is a lifting structure system, and the second core system is an active control system. The auxiliary system is excavated step by step like going up and down steps, and the auxiliary system can not be applied under the condition of good sedimentation control effect. Wherein the lift architecture system used herein is unique to the present method, the manner in which the active control system is arranged is also unique to the present method, and the auxiliary system is also visible in other traversing methods.

2. The core system of the method is a pure structure system, and compared with the deformation protection system formed by deep hole grouting or freezing and the like through the existing rail transit underground structure in the past, the method has the advantages of being computable (the sedimentation control effect formed by deep hole grouting, freezing and the like is not capable of being calculated in an accurate theory), so that the deformation control mechanism is simpler, more convenient and more definite.

3. The deformation control is simple and clear, the operation is simple and convenient, and the manufacturing cost and the construction period are controllable.

4. The main deformation protection measures are vertical lifting and horizontal lifting structures and hydraulic jacks, the formed active protection system is unique, but the active protection system is developed based on a mature technology, the operation is not difficult, the engineering quantity is very small (compared with most of vertical crossing which is relatively mature in the prior art, the quantity of cement and steel materials which are put into the active protection system is small), and meanwhile, the put-in hydraulic jacks can be taken out and can be recycled, so that the active protection system is simple, convenient, and cost and construction period are controllable.

The details of the present invention can be found in the following description and the accompanying drawings.

Drawings

Fig. 1 shows a step sequence diagram one of an active control method of the ultra-small clear distance long-distance oblique crossing rail transit existing underground structure.

FIG. 2 shows a second step chart of the present invention.

Figure 3 shows a third step diagram of the present invention.

Figure 4 shows a fourth step diagram of the present invention.

Fig. 5 shows a fifth step sequence diagram of the present invention.

Fig. 6 shows a step sequence diagram six of the present invention.

Fig. 7 shows a step sequence diagram seven of the present invention.

Fig. 8 shows a partially enlarged schematic view of fig. 7.

Fig. 9 shows a schematic view of a traversing structure according to the present invention.

Fig. 10 shows a schematic of the method of the present invention.

Reference numerals:

101. existing rail transit structures; 102. newly-built rail transit structures; 103. a lifting structure; 10. a vertical lifting structure; 11. adding a sprayed concrete structure on the vertical steel grating; 12. a steel pile casing; 13. a vertical reinforcement cage; 14. vertically pouring concrete; 15. the steel bars are mutually anchored into the structure; 16. a plain concrete structure; 20. a lateral lifting structure; 21. a transverse reinforcement cage; 22. reserving a movable steel installation position; 23. embedding a hydraulic jack fixing support; 24. a movable steel structure; 25. a hydraulic jack; 26. a steel gasket; 27. supporting the section steel; 31. a step is arranged; 32. descending a step; 33. newly-built structural primary support; 34. advanced support; 35. welding a structure; 36. grouting pipe.

Detailed Description

Referring to fig. 1 and 2, the active control method of the existing underground structure of the ultra-small clear distance long-distance oblique crossing rail transit is shown.

The method is suitable for the construction of the underground crossing engineering of the track traffic, as shown in fig. 9, the newly built track traffic structure 102 crosses the existing track traffic structure 101, the newly built track traffic structure 102 is excavated according to the arrow direction, and a plurality of lifting structures 103 are measured at the crossing section of the existing track traffic structure 101;

(1) An in-service rail transit subterranean structure, or other similar subterranean structure.

(2) The existing operation rail transit structure is a structure with continuous rigidity, such as a cast-in-situ reinforced concrete frame structure and the like.

(3) The bottom plate of the existing operation rail traffic structure is a flat plate or a structure similar to the flat plate.

(4) The transport is ultra-small clear distance long-distance oblique crossing or other oblique crossing in crossing mode.

(5) The bottom burial depth of the existing rail transit structure is not more than 20m.

The active control method for the existing underground structure of the ultra-small-clear-distance long-distance oblique crossing rail transit comprises the following steps:

step one: and collecting the archival data of the underground structure of the operation rail transit, and simultaneously performing on-site investigation. The detection shows that the plane and vertical positions of the existing operation track traffic underground structure, geomechanical parameters of stratum, geometric dimension information of the existing track traffic structure 101, track structure and other relevant information.

Step two: the existing track traffic structure 101 and the track structure are subjected to current situation detection, the current situation mechanical properties of the existing track traffic structure 101 and the track structure are evaluated, and the capability of the existing track traffic structure and the track structure to continue deformation is judged according to the information such as crack development degree, carbonization degree and steel bar corrosion degree. The decision to continue deformability is based on calculations that are performed in accordance with current national regulations. The existing track traffic structure and the track structure after continuous deformation are required to meet the requirements of bearing capacity, deformation limit values of structural members, durability and train running safety. After the structure continues to deform, the maximum deformation value which simultaneously meets the requirements of bearing capacity, deformation limit value of the structural member, durability and train running safety requirement is the structure continuous deformation control value W. In one embodiment, the structure continuation deformation control value W is determined as follows.

And calculating a deformation limit value (W1 for short) corresponding to the bearing capacity, and establishing a load structure model through finite element software for analysis. And (3) simulating deformation of the structure in the crossing process in analysis, wherein under the deformation effect, when any one of bending moment, shearing force and axial force generated in the operated structure and the rail is about to exceed the limit, the corresponding deformation value is the deformation limit W1 corresponding to the bearing capacity.

Wherein, the deformation limit value (W2) corresponding to the deformation limit value (v 1, v2, v3 … …) of the structural member is analyzed by establishing a load structure model through finite element software. And simulating deformation of the structure in the crossing process in the analysis, carrying out statistics recording on deformation of each beam, plate, column and other components of the structure under the deformation, comparing and analyzing the statistics recording result with the deformation limit value of the components in the original determined drawing, and obtaining the deformation limit W2 corresponding to the deformation limit value of the components in the original determined drawing when any one of the beam, plate, column and other components of the structure is reached.

And (3) calculating a deformation limit value (W3 for short) corresponding to the durability, and establishing a load structure model through finite element software for analysis. And (3) simulating deformation of the structure in the crossing process in the analysis, calculating crack values of each beam, plate, column and other components of the structure under the deformation, comparing and analyzing the statistical record results with the crack limit values in the original determined drawing, and obtaining the deformation limit W3 corresponding to the fact that any crack of each beam, plate, column and other components of the structure reaches the component crack limit values in the original determined drawing.

The calculation of the deformation limit value (abbreviated as W4) of the train running safety requirement is performed by analyzing the rail deformation allowable value, and the rail deformation allowable value is directly equal to W4 because the rail is closely attached to the structure.

The minimum value of W1, W2, W3, W4 is taken as the structure continued deformation control value W.

Step three: after the continuous deformation control value W of the existing operation track traffic underground structure is determined, the active lifting structure system determination of the existing operation track traffic underground structure is started. When the active lifting structure system is used for a newly built structural engineering to pass through an operation rail transit underground structure, the safety use of the existing line traveling crane is ensured, the active lifting structure system bears the soil load, the track bed load, the track load, the vehicle load and the load of all relevant civil works and equipment facilities in the track extending area above the existing operation rail transit underground structure, and the determination of the active lifting structure system can comprise the following contents:

and 3.1, determining the structural lifting point positions. The determination of the lifting point position is carried out according to the following method:

the lifting point position determination should consider the influence of subsequent lifting structure construction on the safety of the existing operation track traffic line, avoid the too close facilities such as distance operation track traffic vehicles, contact net, cables and the like during construction, influence the existing line operation safety, and simultaneously, the lifting point position determination should reduce the damage of subsequent newly built structure engineering construction on the lifting structure as far as possible.

And 3.2, after the points are distributed according to the principle of the two points, calculating and analyzing, wherein a load structure model is adopted for analysis, the model only contains the existing operation rail transit underground structure, the lifting point position adopts the constraint of only limiting the vertical displacement, other positions adopt foundation springs, the foundation springs corresponding to the excavation positions are processed according to failure, and the load is loaded according to the actual load. After calculation and analysis, if one of the following conditions occurs, the lifting point position is determined again, the point position arrangement is adjusted, and the distance between the lifting point positions is reduced until the requirements are met.

(1) The structure does not meet the load-bearing capacity determination requirements.

(2) The structure continues to deform beyond 30% of the control value W.

Step four: and after the lifting point positions are determined, determining an active lifting structural system. The active lifting structure system consists of an existing operation rail transit underground structure and a lifting structure 103, wherein the lifting structure is divided into a vertical lifting structure and a horizontal lifting structure. The vertical lifting structure is arranged at the lifting point position, and the horizontal lifting structure is arranged on the upper part of the vertical lifting structure.

The vertical lifting structure is determined as follows.

The method determines that the influence of construction on the existing line operation safety is considered, and the influence of standing of construction machinery and construction on operation trains and operation equipment is considered. Construction safety isolation measures are set if necessary.

On the premise of ensuring operation safety, large-scale mechanical construction is adopted preferentially. When large-scale machinery construction has operation potential safety hazards in the aspects of machinery dumping, reinforcement cage hoisting and the like, manual construction is adopted.

The planar dimensions of the vertical lifting structure should be as small as possible in order to avoid subsequent structural chiseling as much as possible.

The vertical lifting structure is inevitably chiseled out in the long-distance oblique crossing existing rail transit underground structure, so that reservation pre-buried determination is made in the determination.

The vertical lifting structure should have sufficient vertical bearing capacity and deformation resistance, wherein the vertical bearing capacity is realized by the friction force between the structure and soil and the end bearing capacity. The calculation of bearing capacity and deformation resistance is carried out according to building foundation determination standard and building pile foundation technical standard.

The transverse lifting structure is determined as follows.

Firstly, transversely lifting the width of a structural member, and taking the following factors into consideration;

and taking all vertical loads P1, P2 and P3 … … of the area served by each lifting structure by the load, performing partial pressure checking calculation according to P1, P2 and P3 … …, and obtaining the widths W1, W2 and W3 … … required by the transverse lifting structure under the condition of ensuring that the bearing capacity and durability index of the existing rail transit structure are not out of limits.

The layout mode of the hydraulic jacks is determined, in order to ensure uniform jacking, the number of the hydraulic jacks arranged in each transverse lifting structure is not less than 2, according to the specific widths of W1, W2 and W3 … …, the hydraulic jacks are distributed as much as possible under the condition of space permission, so that the number of the hydraulic jacks at the transverse lifting positions is determined, and the number of the hydraulic jacks is divided by P1, P2 and P3 … …, so that the model of the hydraulic jacks is determined.

Step five: after the active lifting structure system is determined to be finished, performing construction of a newly built rail transit structure to traverse the existing operation rail transit structure, wherein the construction comprises the following implementation steps;

and 5.1, as shown in fig. 1 and 2, a vertical lifting structure 10 is arranged at the position of the fixed lifting point, and the vertical lifting structure 10 recommends a small manually operated shaft with the inner diameter of 1200mm for protecting the safety of the existing line to the greatest extent. The vertical lifting structure is supported by adopting a mode of adding a vertical steel grating and spraying concrete structure 11 during excavation, and the vertical steel grating and spraying concrete structure 11 comprises a vertical reinforcement cage 13 and vertical poured concrete 14. The depth of the shaft excavation takes the continuous deformation control value W as a control value, and is determined by sedimentation analysis, wherein the sedimentation analysis needs to consider the influences of the friction resistance and the end resistance of the soil layer.

The steel pile casing 12 is arranged in a vertical lifting structure (also a vertical lifting structure which can collide with a new structure) to be chiseled off in the later period, the inner diameter of the steel pile casing 12 made of all steel is preferably 1200mm, wherein the length of the steel pile casing 12 along the excavation direction of the vertical lifting structure 10 is 350mm, the steel pile casing is arranged at the primary support connection position of the new structure in the later period, and the vertical steel grid and shotcrete structure 11 is not arranged at the arrangement position. To increase the stability of the steel casing 12, built-in beard ribs (beard ribs should avoid collision with the main ribs of the subsequent lifting structure) can be added at the steel casing, and at the same time, the beard ribs are connected with the vertical steel grid and shotcrete structure 11 through longitudinal connecting ribs (see fig. 1).

Step 5.2, as shown in fig. 2 and 3, a transverse lifting structure 20 is arranged in the vertical lifting structure 10, and the transverse lifting structure 20 is formed by excavating inwards from the upper end of the vertical lifting structure 10, and the specific method is as follows:

and determining the width of the clearance in excavation according to the widths W1, W2 and W3 … … of the components of the transverse lifting structure by 200mm, and setting the U-shaped structure of steel grating and shotcrete on the bottom plate of the primary support side wall of the transverse lifting structure at the position of the hydraulic jack.

After the primary support of the transverse lifting structure is closed, a transverse reinforcement cage of a lower stress system is placed in the transverse reinforcement cage (the transverse reinforcement cage can be provided with anchor bars for anchoring the vertical lifting structure) and concrete is poured, after the concrete pouring is finished and the strength is reached, an embedded hydraulic jack fixing support 23 is arranged above the concrete pouring, and a reserved movable steel installation position 22 is arranged above the concrete pouring.

The transverse lifting support roof adopts a movable steel structure 24 which is provided with a constraint mechanism, and can only move up and down and can not move left and right and rotate.

The hydraulic jacks 25 are arranged at the positions of the embedded hydraulic jack fixing supports 23, the number of the hydraulic jacks is determined according to the content, and the hydraulic jacks 25 are prevented from being displaced after being stressed through the embedded hydraulic jack fixing supports 23.

Step 5.3 (see fig. 2 and 3), and applying mutual anchor reinforcement cages in the vertical lifting structure, wherein the mutual anchor reinforcement cages and the reinforcement anchored by the transverse reinforcement cages in the transverse lifting structure and the internal beard reinforcement of the all-steel pile casing form a reinforcement mutual anchoring structure 15 together. After the construction of the mutual anchor reinforcement cage is finished, concrete is poured to form an integral vertical lifting structure to the base position of the transverse lifting hydraulic jack. The vertical lifting structure and the transverse lifting structure form an integral lifting structure together. The method is used for solving the problem that soil under the existing operation track traffic structure loses the lifting effect after the lifting effect on the existing structure because of excavation, and the existing track traffic structure is prevented from sedimentation caused by excavation. The hydraulic jack is used for active lifting of existing lines. All active lift structures are formed so far.

Step 5.4 (see fig. 4): a lead support 34 for the newly built rail transit structure is implemented. The construction of the newly built structure primary support 33 is performed by adopting an equal-division method of the upper step 31 and the lower step 32 so as to reduce the influence on the existing line. The primary support adopts a steel grid and sprayed concrete.

When the newly built rail transit structure and the vertical lifting structure do not conflict, the excavation is independently carried out, and the excavation is independently looped.

When the new track traffic structure starts to conflict with the vertical lifting structure, the new structure primary support 33 is separated, a weldable gusset plate is arranged on the steel grating, and the gusset plate is connected with a steel pile casing reserved in the vertical lifting structure through a welding structure 35, so that early sealing is realized, control risk is reached, and sedimentation is reduced.

Step 5.5 (see fig. 4): during the excavation of the newly built track traffic structure, settlement monitoring should be performed in real time, and if the deformation of the existing track traffic structure exceeds the limit value of the continuous deformation capacity, the hydraulic jack is used for jacking the existing track traffic structure, so that the deformation of the existing track traffic structure is ensured not to exceed the limit.

Step 5.6 (see fig. 5): the existing line lower soil body is subjected to low-pressure grouting through the grouting pipe 36, loss is fed back timely, settlement is not generated after construction, and cement-based slurry is needed to ensure the settlement control effect.

Step 5.7 (see fig. 6): and continuing construction until the newly built waterproof and permanent structure is completed.

Step 5.8 (see fig. 7): in the area where the hydraulic jack is arranged, the hydraulic jack is replaced by a structure for supporting the steel gasket 26 by the section steel 27, so that the hydraulic jack is taken out, and the engineering investment is saved. The following requirements are required to be met in the construction process;

(1) firstly, adding supporting section steel 27 to lift the steel gasket 26, unloading the hydraulic jack after the steel gasket is firmly lifted, and taking out the hydraulic jack.

(2) And the current wires are taken out in sections according to the monitoring result so as to ensure the safety of the existing wire sedimentation control.

Step 5.9 (see fig. 7): and pouring vertical shaft concrete of the vertical lifting structure to form a plain concrete structure 16 to the natural ground, and completing the whole construction.

Therefore, the invention can realize the sedimentation control effect which cannot be achieved by other crossing methods through the unique deformation control system, thereby ensuring the operation safety of the existing operation rail transit line during crossing construction. Meanwhile, the operation is simple and convenient, and the manufacturing cost and the construction period are controllable.

Compared with other methods for traversing the existing operation rail transit underground structure, the method has the following characteristics:

It is to be clearly understood that the above description and illustration is made only by way of example and not as a limitation on the disclosure, application or use of the invention. Although embodiments have been described in the embodiments and illustrated in the accompanying drawings, the invention is not limited to the specific examples illustrated by the drawings and described in the embodiments as the best mode presently contemplated for carrying out the teachings of the invention, and the scope of the invention will include any embodiments falling within the foregoing specification and the appended claims.

Claims

1. An active control method for an existing underground structure of ultra-small-clear-distance long-distance oblique crossing rail transit is characterized by comprising the following steps:

2. The active control method for the ultra-small clear distance long-distance oblique crossing rail transit existing underground structure is characterized by comprising the following steps of: the structure continuous deformation control value W takes one of the minimum value of a deformation limit value W1 corresponding to the bearing capacity, a deformation limit value W2 corresponding to the deformation of the structural member, a deformation limit value W3 corresponding to the existing structural crack and a deformation limit value W4 corresponding to the train running safety.

3. The active control method for the ultra-small clear distance long-distance oblique crossing rail transit existing underground structure is characterized by comprising the following steps of: the deformation limit value W1 corresponding to the bearing capacity is analyzed by establishing a load structure model through finite element software, the deformation of the structure in the crossing process is simulated, and under the deformation effect, when any one of bending moment, shearing force and axial force generated in the operated structure and the track is about to exceed the limit, the corresponding deformation value is the deformation limit value W1 corresponding to the bearing capacity;

4. The active control method for the ultra-small clear distance long-distance oblique crossing rail transit existing underground structure is characterized by comprising the following steps of: the lifting point position determination should consider the influence of subsequent lifting structure construction on the safety of the existing operation track traffic line, avoid too close facilities of distance operation track traffic vehicles, contact networks and cables during construction, influence the existing line operation safety, and simultaneously, the lifting point position determination should reduce the damage of subsequent newly built structure engineering construction on the lifting structure.

5. The active control method for the ultra-small clear distance long-distance oblique crossing rail transit existing underground structure is characterized by comprising the following steps of: the vertical lifting structure should consider the influence of construction on the operation safety of the existing line, and mainly consider the influence of standing of construction machinery and construction on operation trains and operation equipment, and construction safety isolation measures should be set.

6. The active control method for the ultra-small clear distance long-distance oblique crossing rail transit existing underground structure is characterized by comprising the following steps of: the width of the components of the transverse lifting structure is checked by partial pressure according to P1, P2 and P3 … … after loading all vertical loads P1, P2 and P3 … … of the area served by each lifting structure, and the width required by the transverse lifting structure is obtained under the condition of ensuring that the bearing capacity and durability index of the existing rail transit structure are not exceeded.

7. The active control method for the ultra-small clear distance long-distance oblique crossing rail transit existing underground structure is characterized by comprising the following steps of: and not less than 2 hydraulic jacks are arranged in each transverse lifting structure.

8. The active control method for the ultra-small clear distance long-distance oblique crossing rail transit existing underground structure is characterized by comprising the following steps of: step five, the following implementation steps are included;

9. The active control method for the ultra-small clear distance long-distance oblique crossing rail transit existing underground structure according to claim 8, which is characterized by comprising the following steps: and 5.8, firstly adding supporting section steel to lift the steel gasket, unloading the hydraulic jack after the steel gasket is firmly lifted, and taking out the hydraulic jack.

10. The active control method for the ultra-small clear distance long-distance oblique crossing rail transit existing underground structure according to claim 9, which is characterized by comprising the following steps: and taking out the wires in sections according to the monitoring result so as to ensure the safety of existing wire sedimentation control.