Background technology
Along with developing rapidly of urban construction, urban rail transit construction has welcome fast-developing paces.Adopted shield Method to build subway tunnel at present in China's urban rail transit construction in a large number.And shield structure turnover hole construction technology is most important in construction as the important component part of shield tunnel construction.
For guaranteeing the safety in shield structure turnover hole, the inlet and outlet cave soil body must have good stable and sealing, and the hole soil body does not cave in, prevents that underground water from pouring in the shield structure active well when making shield structure turnover hole.During the hole of shield structure turnover in the past, the outer soil body of portal generally is by carrying out consolidation process on the ground, treating to carry out the detection of soil layer consolidation effect before the shield structure turnover hole; When the soil layer consolidation effect is not good outside finding portal, can replenish reinforcing, to satisfy shield structure turnover hole construction requirement from ground.Such as carry out vertical churning, stirring or freezing by ground the outer soil body of portal is replenished reinforcing.
But the exploitation of urban underground space develops to the densification direction, and it is all the more complicated that the subway tunnel built environment is also becoming, and at present this mode of carrying out the hole consolidation process by ground can't satisfy the requirement of construction sometimes.
As shown in Figure 1, it is a kind of schematic diagram of subterranean tunnel environmental structure, wherein shield tunnel 11 and road tunnel 12 conllinear, and shield tunnel 11 is positioned at the below of road tunnel 12.From the surrounding structure of shield tunnel 11, the top is the road tunnel structure base plate 13 that has built up, and there are foundation pit enclosure structure 14(such as diaphragm wall in both sides), form the three side sealing closed loop border that all there is continuous structure the top and the left and right sides.And under three side sealing closed loop border, reinforce and replenish the structure influence that reinforcing all can be subjected to having constructed the early stage of the outer soil layer of portal, can't from ground, directly construct, strengthening construction needs penetratingly to descend road structure, can't implement.
And for example shown in Figure 8, it is the schematic diagram of another kind of subterranean tunnel environmental structure.The top of the shield tunnel 81 among this figure and the left and right sides have equally also formed three side sealing closed loop border, and reinforce and replenish reinforcing and also can't directly construct from ground the early stage of the outer soil layer of portal.
This shows, outside portal soil layer top and the left and right sides all have under the three side sealing closed loop border of structure shield structure turnover hole construction with in the past conventional construct different.Yet, yet there are no the similar engineering case at present at home and abroad, the shield structure that must adopt new job practices solution three side sealing to close under the built structure passes in and out a hole construction technology difficult problem.
Summary of the invention
The purpose of this invention is to provide a kind of three side sealing and close shield structure turnover cavity construction method under the built structure, can't adopt ground reinforcing and ground to replenish the problem of reinforcing with the shield structure turnover hole construction that solves under the three side sealing closed loop border.
The present invention proposes a kind of three side sealing and closes shield structure turnover cavity construction method under the built structure, may further comprise the steps: (1) is carried out early stage to the outer soil body of portal and is reinforced, and reinforces described early stage before the construction of portal superstructure and implements.(2) the soil stabilization effect is detected, described detection is implemented in portal superstructure construction back.(3), then adopt the horizontal frozen method that the outer soil body of portal is replenished reinforcing if the soil body does not reach intensity and sealing requirement.(4) implement shield structure turnover hole tunneling construction.
Close under the built structure shield structure turnover cavity construction method according to the described three side sealing of preferred embodiment of the present invention, replenish when reinforcing and specifically may further comprise the steps: (1) horizontal drilling on the soil body outside portal.(2) in lateral aperture, bury freezing pipe underground.(3) the outer soil body of portal is actively freezed, form the consolidation by freezing body.
Close shield structure turnover cavity construction method under the built structure according to the described three side sealing of preferred embodiment of the present invention, freeze also to comprise step after shield structure turnover hole tunneling construction is finished under the additional reinforcing condition in employing: (1) implements to force to thaw to freezing the soil body.(2) pull out freezing pipe, and slip casting in time in the hole that tube drawing forms.
Close under the built structure shield structure turnover cavity construction method according to the described three side sealing of preferred embodiment of the present invention, the soil stabilization effect is detected specifically comprise step: (1) offers thief hole on the soil body.(2) the sampling soil in the thief hole is carried out intensity detection.(3) judge the consolidation effect of the soil body according to the testing result of sampling soil.
Close under the built structure shield structure turnover cavity construction method according to the described three side sealing of preferred embodiment of the present invention, the soil stabilization effect is detected also comprise: observe in the thief hole whether percolating water or mud are arranged.
Close shield structure turnover cavity construction method under the built structure according to the described three side sealing of preferred embodiment of the present invention, specifically comprise step when implementing shield structure turnover hole tunneling construction: (1) measures the temperature of freezing the soil body in real time.(2) judge according to variations in temperature whether the consolidation by freezing body reaches requirement of strength.(3), then implement shield structure turnover hole tunneling construction if reach requirement of strength.
Close shield structure turnover cavity construction method under the built structure according to the described three side sealing of preferred embodiment of the present invention, adopt high-pressure rotary-spray or agitation pile to carry out early stage to the outer soil body of portal and reinforce.
The invention has the beneficial effects as follows: the present invention adopts the horizontal frozen method that the outer soil body of portal is replenished reinforcing; the portal soil mass consolidation is possessed under the prerequisite of advantages such as compliance is strong, stagnant water effect good, safe and reliable; more can be to hole surrounding environment structure; especially top and left and right sides built structure play a good protection, solved existing hole reinforcing technique the difficult problem that can't handle.
The specific embodiment
Main thought of the present invention is to adopt the horizontal frozen method that the outer soil body of the portal under the three side sealing closed loop border is replenished reinforcing; make the shield structure turnover hole section soil body reach design strength and stagnant water effect; for shield structure turnover hole construction provides a safe and reliable working environment; and can be to surrounding environment, especially top and left and right sides built structure play a good protection.Method of the present invention all can be implemented under abominable complex geological conditions such as weak soil, high hydraulic pressure, is particularly useful for the shield structure turnover hole construction under the urban compact district complex environment.
Specify the present invention below in conjunction with accompanying drawing.
See also Fig. 2, it closes a kind of embodiment flow chart of the turnover of shield structure under built structure cavity construction method for three side sealing of the present invention, and it may further comprise the steps:
S201 carries out early stage to the outer soil body of portal and reinforces.
S202, construction portal superstructure.
S203 detects the soil stabilization effect.Pass through if detect, then enter step S207; Do not pass through if detect, then enter S204.
S204 adopts the horizontal frozen method that the outer soil body of portal is replenished reinforcing.
S205 implements shield structure turnover hole tunneling construction.
S206 is to consolidation by freezing body force to thaw (only implementing this step) when S204 is arranged.
S207 implements shield structure turnover hole tunneling construction.
Before the superstructure construction, at first the outer soil body of portal is reinforced (being step S201) in advance.Reinforcement means can adopt high-pressure rotary-spray or agitation pile, and preferable stabilization zone thickness is that portal outer shield structure axis direction extends 6m, and portal each side extends 3m to both sides, depth direction by portal below 3m to the structure base plate of portal top.The foundation pit enclosure structure of the outer left and right sides of portal can be constructed before or after pre-the reinforcing and all can.Pre-reinforcing should be implemented in the certain hour before shield structure turnover hole construction, thereby guarantees that the shield structure has reached the desired design requirement of strength when passing in and out the hole construction.
After shield structure turnover hole section portal soil stabilization finishes, can implement the normal construction (being step S202) of superstructure.Here said superstructure is meant the underground building structure of portal top, as road tunnel etc.The construction of superstructure should meet relevant design and job specfication requirement, and avoids destroying pre-soil mass consolidation at work progress as far as possible.Catchment etc. and all can influence the actual consolidation effect of the pre-soil mass consolidation in below in the end of backbreaking, cheat during as top structure excavation of foundation pit.
Before the shield structure turnover hole construction, must detect (being step S203), judge whether it possesses shield structure turnover hole execution conditions the outer soil stabilization effect of portal.The soil stabilization effect detection can be by offering thief hole on the inherent concrete portal of shield structure active well, observe earlier whether percolating water or mud phenomenon are arranged, carry out drill hole sampling again, and the soil of taking a sample is carried out intensity detection, judge whether soil mass consolidation reaches the design strength requirement.Simultaneously, whether there are percolating water or mud also to need Real Time Observation in the hole after the sampling.Perforate quantity and position should be implemented according to relevant design and job specfication, to reach overall understanding soil stabilization whole structure.
Observe and sampling soil strength test case according to perforate, judge the outer soil stabilization effect of shield structure turnover hole portal, whether decision replenishes reinforcing to the soil body.If soil strength and stagnant water effect have reached designing requirement, then can directly implement shield structure turnover hole tunneling construction (being step S207).As the soil strength of taking a sample fails to reach, and its design strength that should possess requires, tapping has more continuous percolating water or mud phenomenon, illustrate that then the outer soil stabilization intensity of portal is not good for not meeting design requirement, add the solid stagnant water effect, do not possess shield structure turnover hole execution conditions, should be defined as and to replenish consolidation process to the soil body.
After determining to replenish reinforcing, consider the existing underground structure base plate in the outer soil body of portal top, the present invention adopts the horizontal frozen method to implement additional reinforce (being step S204).Wherein, adopt the horizontal frozen method to replenish the preferable implementation of reinforcing and specifically can take following steps, as shown in Figure 3:
S301, horizontal drilling on the soil body outside portal.
S302 buries freezing pipe underground in lateral aperture.
S303 actively freezes the outer soil body of portal, forms the consolidation by freezing body.
It should be noted that, to in conjunction with the outer soil layer geological conditions of portal, groundwater table and peripheral load situation, carry out the horizontal frozen reinforcing design and calculate according to soil stabilization effect detection situation, determine consolidation by freezing body thickness and reinforcing scope, the layout of clear and definite horizontal frozen pipe and freeze pipe range etc.On portal, press the designing requirement perforate, and outside portal, hole in the soil body and bury freezing pipe underground.
See also Fig. 4, it is for burying a kind of schematic diagram of freezing pipe underground in the soil body outside portal.Wherein, in the many freezing pipe 41 horizontally embedded soil bodys outside portal 42, and the horizontal frozen pipe 41 buried underground is connected to freezing equipment (because freezing equipment places on the ground usually by pipeline 43 successively, thereby do not illustrate among the figure), and cooperate the equipment such as temperature tube and temperature transducer that freeze, the portal 42 outer soil bodys are actively freezed, and form soil mass consolidation 44, possesses stagnant water effect and certain intensity, for shield structure turnover hole construction provides reliable working environment.Wherein, can adopt salt solution or liquid nitrogen circulating frozen liquid as freezing equipment.
After the soil body satisfies requirement of strength outside portal, just can implement shield structure turnover hole tunneling construction (being step S205).And in order to ensure safety of construction, also will soil mass consolidation 44 be monitored in real time, seeing also Fig. 5, specifically can may further comprise the steps during the shield driving construction:
S501 measures the temperature of freezing the soil body in real time.
S502 judges according to variations in temperature whether the consolidation by freezing body reaches requirement of strength.
S503 if reach requirement of strength, then implements shield structure turnover hole tunneling construction.
Monitoring according to temperature, after soil mass consolidation 44 reaches designing requirement, freezing equipment is kept to be freezed, and keep under the frozen state that the routine of implementing portal cuts, shield cutter leans on the consolidation by freezing body, shield cutter cutting soil mass consolidation 44, portal sealing, finish shield structure turnover hole tunneling construction.Please respectively referring to Fig. 6 and Fig. 7, the schematic diagram that Fig. 6 appears for the shield structure, Fig. 7 are the schematic diagram of shield.Before the shield structure was appeared, at first shield machine 61 should be ready in the active well 62 that starts, and after soil mass consolidation 44 satisfies intensity and sealing requirement, cuts portal, and the cutterhead of shield machine 61 just can cut and pass through soil mass consolidation 44, and then carry out the tunneling construction in tunnel.Before the shield, shield machine 61 is to be positioned at the constructing tunnel section of having tunneled, and after soil mass consolidation 44 satisfied intensity and sealing requirement, shield machine 61 just can cut and pass through soil mass consolidation 44, and enter from hole 42 and to accept to finish the tunneling construction in tunnel the active well 72.Because the existence of soil mass consolidation 44 for shield structure turnover hole construction provides a safe and reliable working environment, especially plays a good protection to top and left and right sides built structure.
When the shield structure normally passes through the consolidation by freezing body, the portal sealing be in place and sealing effectiveness safe and reliable after, stop to safeguard and freeze, implement to force to thaw (being step S206) to freezing the soil body.Pressure should be pulled out freezing pipe after thawing and finishing, and slip casting in time in the hole that tube drawing forms, and the soil deformation that cause in the hole of avoiding collapsing also can be avoided soil body generation thaw collapse simultaneously, effectively controls stratum deformation.
The present invention adopts the horizontal frozen method to realize the additional reinforcing of the soil body outward of the portal under the three side sealing closed loop border, have advantages such as compliance is strong, stagnant water effect good, safe and reliable, can be applicable to various complex geological conditions, in the complex environment of busy section of town, city, implement shield structure turnover hole construction and have tangible technical advantage.More than disclosed only be several specific embodiment of the present invention, but the present invention is not limited thereto, any those skilled in the art can think variation, all should drop in protection scope of the present invention.