CN116044437A - Tunnel supporting isolation system and construction method thereof - Google Patents
Tunnel supporting isolation system and construction method thereof Download PDFInfo
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- CN116044437A CN116044437A CN202310062144.9A CN202310062144A CN116044437A CN 116044437 A CN116044437 A CN 116044437A CN 202310062144 A CN202310062144 A CN 202310062144A CN 116044437 A CN116044437 A CN 116044437A
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/003—Linings or provisions thereon, specially adapted for traffic tunnels, e.g. with built-in cleaning devices
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/38—Waterproofing; Heat insulating; Soundproofing; Electric insulating
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Abstract
The invention provides a tunnel supporting isolation system, which comprises: the first support piles are respectively positioned at two sides of the tunnel; the second support piles are respectively positioned at one side of the first support pile away from the tunnel; the second support pile corresponds to the position of the first support pile; the tops of the first support piles and the second support piles are connected through connecting plates so as to form portal frame type support isolation pile structures on two sides of the tunnel respectively; the first support piles positioned on the same side of the tunnel are arranged in a row, and the tops of the first support piles are connected through crown beams; the second support piles positioned on the same side of the tunnel are arranged in a row, and the tops of the second support piles are connected through crown beams so as to effectively prevent disturbance of pile foundations on two sides of the tunnel and foundation pit construction processes on the tunnel and adjacent soil bodies; simultaneously through being provided with triaxial stirring stake wall between first support stake and second support stake, prevent the water loss in the karst cave for this scheme still is applicable to the construction protection in karst landform subway tunnel.
Description
Technical Field
The invention relates to the field of construction supporting isolation structures, in particular to a tunnel supporting isolation system and a construction method thereof.
Background
At present, when deep foundation pits and pile foundations are constructed at home and abroad, more researches on the influence and protection of a subway tunnel are carried out, but the existing researches are mainly aimed at the situation of excavating the foundation pit on one side of the subway, and the technical scheme of simultaneously excavating the foundation pits on two sides to protect the subway tunnel is lacking.
Disclosure of Invention
In order to solve the problems, the invention provides a tunnel supporting and isolating system and a construction method thereof, which are used for solving the problem of protecting a subway tunnel when foundation pits on two sides of the subway tunnel are excavated simultaneously.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a tunnel support insulation system comprising:
the first support piles are respectively positioned at two sides of the tunnel;
the second support piles are respectively positioned at one side of the first support pile away from the tunnel; the second support pile corresponds to the position of the first support pile;
the tops of the first support piles and the second support piles are connected through connecting plates so as to form portal frame type support isolation pile structures on two sides of the tunnel respectively;
the first support piles positioned on the same side of the tunnel are arranged in a row, and the tops of the first support piles are connected through crown beams; the second support piles on the same side of the tunnel are arranged in a row, and the tops of the second support piles are connected through crown beams so as to effectively block disturbance of pile foundations on two sides of the tunnel and foundation pit construction processes on the tunnel and adjacent soil bodies.
Further, the tunnel supporting isolation system further comprises a triaxial stirring pile wall; the triaxial stirring stake wall is located between first support stake and the second support stake for cut underground karst water channel, reduce the influence of support stake construction to the tunnel structure.
Furthermore, the triaxial stirring stake wall adopts the triaxial stirring stake of overlap joint formula interpolation shaped steel to form the containment wall body that collects soil retaining and stagnant water function in an organic whole.
Further, the triaxial stirring stake wall is located near one side of the second support stake.
Further, the tunnel supporting isolation system further comprises a hanging net; the hanging net is arranged on the second support pile to protect soil bodies between the first support pile and the second support pile and prevent the soil bodies from caving.
The construction method of the tunnel supporting isolation system is applied to the tunnel supporting isolation system and comprises the following steps of:
the specific gravity of the slurry is increased to increase the liquid column pressure before drilling construction; increasing the height of the drilling barrel, filling clay around the protection barrel, and tamping layer by layer; the number of the slurry discharging holes is increased at the wall of the drill cylinder, so that slurry can be quickly replenished when the liquid level in the slurry discharging holes is reduced;
during drilling construction, a mine type drill is adopted for construction so as to squeeze and build walls and tamp partial filler of a karst cave; forming a stable artificial hole wall by putting a filler consisting of clay and bentonite, and preventing the pile hole wall from collapsing or collapsing; adopting a rotary drilling and forming process, wherein the drilling sequence adopts 'three-jump drilling one', and is carried out in three sequences;
and excavating a connecting plate and a crown beam foundation pit according to the measuring and lofting position after the construction of the support pile is completed, and constructing the crown beam of the support pile top and the connecting plate therebetween.
Further, the construction method of the tunnel supporting and isolating system further comprises the following steps: before the construction operation of the first support pile and the second support pile is carried out, the three-axis stirring pile wall construction is simultaneously and symmetrically carried out on two sides of the tunnel, and the first support pile and the construction follow the three-axis stirring pile wall construction flow operation to intercept underground karst water channels and reduce the influence of the follow-up support pile construction on the tunnel structure as much as possible.
Further, the triaxial stirring pile construction method comprises the following steps:
establishing a karst cave model to pre-judge construction conditions and a pre-cast construction scheme in advance, and timely processing when construction has problems;
optimizing construction process and construction parameters according to karst cave model data, and making a plan for handling slurry leakage hole collapse accidents;
and (5) carrying out triaxial stirring pile construction by using a triaxial stirrer.
Further, the preparation of the plan for handling the slurry leakage hole collapse accident comprises the following steps:
preparing auxiliary materials for emergency use of the rubble and clay; preparing an enlarged mud pit and a sufficient water source, and ensuring that mud has good viscosity and gel rate; close to the karst cave layer, the change of the mud level in the hole needs to be closely noticed, and once the mud is leaked, the mud needs to be quickly supplemented and lifted to drill into the hole to throw and fill the prepared auxiliary materials.
Further, the construction method of the tunnel supporting and isolating system further comprises the following steps: and stopping constructing backfill holes for the karst cave with slurry leakage, and re-drilling after the karst cave is initially set.
The invention provides a tunnel supporting isolation system, which comprises: the first support piles are respectively positioned at two sides of the tunnel; the second support piles are respectively positioned at one side of the first support pile away from the tunnel; the second support pile corresponds to the position of the first support pile; the tops of the first support piles and the second support piles are connected through connecting plates so as to form portal frame type support isolation pile structures on two sides of the tunnel respectively; the first support piles positioned on the same side of the tunnel are arranged in a row, and the tops of the first support piles are connected through crown beams; the second support piles positioned on the same side of the tunnel are arranged in a row, and the tops of the second support piles are connected through crown beams so as to effectively prevent disturbance of pile foundations on two sides of the tunnel and foundation pit construction processes on the tunnel and adjacent soil bodies; simultaneously through being provided with triaxial stirring stake wall between first support stake and second support stake, prevent the water loss in the karst cave for this scheme still is applicable to the construction protection in karst landform subway tunnel.
Drawings
FIG. 1 is a schematic cross-sectional view of a tunnel supporting and insulating system;
FIG. 2 is a schematic plan view of a tunnel supporting and insulating system;
FIG. 3 is a schematic diagram of a screen mounting structure;
fig. 4 is a schematic diagram of a construction method of a tunnel supporting and isolating system.
Reference numerals illustrate: 1-first support piles, 2-second support piles, 3-connecting plates, 4-crown beams, 5-triaxial stirring pile walls, 6-hanging nets, 7-prestressed inhaul cables, 8-ground, 9-subway tunnels and 10-backfilled light plain concrete.
Detailed Description
Embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.
Other advantages and effects of the present disclosure will become readily apparent to those skilled in the art from the following disclosure, which describes embodiments of the present disclosure by way of specific examples. It will be apparent that the described embodiments are merely some, but not all embodiments of the present disclosure. The disclosure may be embodied or practiced in other different specific embodiments, and details within the subject specification may be modified or changed from various points of view and applications without departing from the spirit of the disclosure. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict. All other embodiments, which can be made by one of ordinary skill in the art without inventive effort, based on the embodiments in this disclosure are intended to be within the scope of this disclosure.
Example 1
As shown in fig. 1, 2 and 3, a schematic structural diagram of a tunnel supporting isolation system is shown, which includes:
the first support piles are respectively positioned at two sides of the tunnel;
the second support piles are respectively positioned at one side of the first support pile away from the tunnel; the second support pile corresponds to the position of the first support pile;
the tops of the first support piles and the second support piles are connected through connecting plates so as to form portal frame type support isolation pile structures on two sides of the tunnel respectively;
the first support piles positioned on the same side of the tunnel are arranged in a row, and the tops of the first support piles are connected through crown beams; the second support piles on the same side of the tunnel are arranged in a row, and the tops of the second support piles are connected through crown beams so as to effectively block disturbance of pile foundations on two sides of the tunnel and foundation pit construction processes on the tunnel and adjacent soil bodies.
In specific implementation, the tunnel supporting isolation system further comprises a triaxial stirring pile wall; the triaxial stirring stake wall is located between first support stake and the second support stake, triaxial stirring stake wall's main action is as the water-stop curtain for cut underground karst water channel, when reducing the foundation ditch excavation of subway tunnel both sides, the influence of the decline of foundation ditch water level to peripheral groundwater level especially subway tunnel both sides groundwater level, but its pile body intensity and rigidity are less, can't bear water, soil pressure as the atress component of foundation ditch support, consequently set up between first support stake and second support stake. Preferably, the position of the triaxial stirring pile wall is close to one side of the second supporting pile (namely, far away from the subway tunnel as far as possible), so that the influence of foundation pit precipitation on peripheral underground water level is reduced, the construction quantity near the subway tunnel is reduced, and the influence of the construction of the supporting pile and the triaxial stirring pile wall on the tunnel structure is reduced.
In specific implementation, the triaxial stirring pile wall adopts a triaxial stirring pile of lap joint type inserted section steel to strengthen the strength of the triaxial stirring pile wall so as to form a containment wall integrating a certain soil retaining function and a water stopping function.
In specific implementation, the tunnel supporting isolation system further comprises a hanging net; the hanging net is arranged on the second support pile to protect soil bodies between the first support pile and the second support pile and prevent the soil bodies from caving.
In specific implementation, the tunnel supporting isolation system further comprises a stress inhaul cable if intervention; the pre-stress inhaul cable adopts the steel strand wires, the pre-stress inhaul cable with portal formula support isolation stake structural connection adds the pre-stress pulling force to tunnel one side, can effectively control the deformation of foundation ditch, avoids causing the deformation of subway tunnel when the foundation ditch construction of both sides simultaneously. Furthermore, the two ends of the pre-stress inhaul cable are respectively connected with the first supporting piles which are positioned at the two sides of the subway tunnel and correspond to the positions, so that the portal supporting isolation pile structures at the two sides of the tunnel are connected into a whole, and an integral stress system is formed by opposite pulling after pre-stress is added. Compared with the independent inhaul cables at each side, the method of opposite pulling at the two sides of the tunnel is utilized, under the condition of simultaneous construction of foundation pits at the two sides of the tunnel, the restraint effect of the tunnel supporting and isolating system on the soil inside the tunnel can be enhanced, the horizontal and vertical displacement of the tunnel is reduced, and the tunnel protection effect is improved. Preferably, the prestress inhaul cable is arranged on the ground in a mode of pre-buried sleeve, so that drilling operation during construction of the prestress inhaul cable or the steel anchor rod in the traditional mode is avoided, disturbance of a drilling process on soil and a tunnel is avoided, and construction is more convenient and efficient.
The sleeve is a PVC pipe.
In some projects, because the top of the subway tunnel is close to the ground, the pile load above the ground above the subway tunnel cannot be too heavy, and the on-site assembly and lifting of some large-span diagonal steel galleries are difficult to carry out. The tunnel supporting isolation system can also utilize double portal isolation piles on two sides of the tunnel and opposite-pulling prestress steel strands to form a force transmission structure, dead weight load generated when the steel trusses are assembled is dispersed below the subway tunnel, sliding rails and lifting frames are arranged on the crown beam connecting plates, meanwhile, the crown Liang Lianji plates can also serve as a passage for a crawler crane to walk, the steel trusses and steel corridor on-site assembly and lifting of the subway tunnel load limiting ground are realized, the bearing safety of the tunnel is prevented from being influenced, and the foundation of the additionally constructed structural lifting frames can be avoided.
Example two
Fig. 3 is a schematic flow chart of a construction method of a tunnel supporting and isolating system, which is applied to the tunnel supporting and isolating system and comprises the following steps:
the specific gravity of the slurry is increased to increase the liquid column pressure before drilling construction;
increasing the height of the drilling barrel, filling clay around the protection barrel, and tamping layer by layer;
the number of the slurry discharging holes is increased at the wall of the drill cylinder, so that slurry can be quickly replenished when the liquid level in the slurry discharging holes is reduced;
during drilling construction, a mine type drill is adopted for construction so as to squeeze and build walls and tamp partial filler of a karst cave;
forming a stable artificial hole wall by putting a filler consisting of clay and bentonite, and preventing the pile hole wall from collapsing or collapsing;
and excavating a connecting plate and a crown beam foundation pit according to the measuring and lofting position after the construction of the support pile is completed, and constructing the crown beam of the support pile top and the connecting plate therebetween.
In specific implementation, the construction method of the tunnel supporting isolation system further comprises the following steps: before the construction operation of the first support pile and the second support pile is carried out, the three-axis stirring pile wall construction is simultaneously and symmetrically carried out on two sides of the tunnel, and the first support pile and the construction follow the three-axis stirring pile wall construction flow operation to intercept underground karst water channels and reduce the influence of the follow-up support pile construction on the tunnel structure as much as possible. The triaxial stirring pile wall adopts a phi 850@600 triaxial cement soil deep stirring pile, the pile length is 21-29 m, and rock entering is required. The construction is carried out by adopting a two-spraying two-stirring process and a one-hole sleeving method. The pile body curing agent adopts P.O42.5 ordinary silicate cement, the single pile cement mixing amount is not less than 200kg/m, the cement replacement rate is 22%, and the cement consumption is not less than 360kg/m3. The cement slurry water-cement ratio is controlled to be about 1.5-1.8.
In the concrete implementation, the construction quality of the deep mixing pile directly influences the water blocking effect of the foundation pit waterproof curtain. And the positions of the weak interlayer, the breaking belt, the soil hole, the karst cave and the like are easy to cause pile failure due to larger gaps and more slurry flows out in the process of spraying slurry. Therefore, the triaxial stirring pile construction comprises the following steps: establishing a karst cave model to pre-judge construction conditions and a pre-cast construction scheme in advance, and timely processing when construction has problems; optimizing construction process and construction parameters according to karst cave model data, and making a plan for handling slurry leakage hole collapse accidents; and (5) carrying out triaxial stirring pile construction by using a triaxial stirrer. Preferably, the optimized construction process comprises adding a group of drills on the blades of the stirrer, adding 2 more blades on the basis of 2×2=4 blades, and increasing stirring efficiency so as to improve stirring uniformity. Preferably, the optimized construction parameters comprise the working time of Duan Shi of poor geology, the stirring speed is reduced, the grouting pressure is increased, and the nozzle pressure of the grouting pipe is ensured to be more than 0.5 MPa. Preferably, the preparation of the plan for handling the slurry leakage and hole collapse accident comprises the following steps: preparing auxiliary materials for emergency use of the rubble and clay; preparing an enlarged mud pit and a sufficient water source, and ensuring that mud has good viscosity and gel rate; close to the karst cave layer, the change of the mud level in the hole needs to be closely noticed, and once the mud is leaked, the mud needs to be quickly supplemented and lifted to drill into the hole to throw and fill the prepared auxiliary materials.
In specific implementation, the construction method of the tunnel supporting isolation system further comprises the following steps: and stopping constructing backfill holes for the karst cave with slurry leakage, pumping mortar (concrete) according to a karst cave treatment mode, filling the mortar (concrete) to the position 1m above the karst cave, and re-drilling after the karst cave is initially set.
Example III
Fig. 3 is a schematic flow chart of a construction method of a tunnel supporting and isolating system, which comprises the following steps:
1. and (6) constructing a triaxial stirring pile wall.
The foundation pit support structure is firstly constructed with the stirring piles, then the supporting piles are constructed, underground karst water channels are cut off after the construction of the stirring piles, and the influence of the construction of the supporting piles on the subway tunnel structure is reduced as much as possible. The two sides and the corner support of the subway adopt phi 850@600 triaxial cement soil deep mixing piles, the pile length is 21-29 m, and rock entering is required. The construction is carried out by adopting a two-spraying two-stirring process and a one-hole sleeving method. The pile body curing agent adopts P.O42.5 ordinary silicate cement, the single pile cement mixing amount is not less than 200kg/m, the cement replacement rate is 22%, and the cement consumption is not less than 360kg/m3. The cement slurry water-cement ratio is controlled to be about 1.5-1.8.
(1) Stirring pile mechanical arrangement and walking route
The field is arranged according to 3 areas: east area, west area and subway protection area. And 3 cement stirring pile machines and 2 triaxial stirring pile machines are arranged, and the two sides of the tunnel are symmetrically constructed at the same time.
(2) Construction process optimization of mixing piles in karst areas
The construction quality of the deep mixing pile directly influences the water blocking effect of the foundation pit waterproof curtain. And the positions of the weak interlayer, the breaking belt, the soil hole, the karst cave and the like are easy to cause pile failure due to larger gaps and more slurry flows out in the process of spraying slurry. The construction process of the stirring pile is optimized mainly by adopting the following measures:
(1) pre-judging in advance and processing in time by using a BIM karst cave model;
(2) optimizing construction process, adding a group of drill bits on the blades of the stirrer, adding 2 more blades on the basis of original 2×2=4 blades, and increasing stirring efficiency to improve stirring uniformity;
(3) optimizing construction parameters: when the poor geological section is constructed, the stirring speed is reduced, the grouting pressure is increased, and the nozzle pressure of the grouting pipe is ensured to be more than 0.5 MPa;
(4) and stopping construction of backfill holes for the karst cave with a large amount of slurry leakage. Pumping mortar (concrete) according to a karst cave treatment mode, filling the mortar (concrete) to a position 1m above the karst cave, and drilling again after the mortar is initially set;
(5) and preparing a slurry leakage hole collapse accident prevention and treatment plan. Preparing auxiliary materials for emergency such as rubble, clay and the like; preparing an enlarged mud pit and a sufficient water source, and ensuring that mud has good viscosity and gel rate; close to the karst cave layer, the change of the mud level in the hole needs to be closely noticed, and once the mud is leaked, the mud needs to be quickly supplemented and lifted to drill into the hole to throw and fill the prepared auxiliary materials.
2. And constructing a first support pile and a second support pile.
The diameters of the support piles are phi 1000 and phi 800 respectively, and a rotary digging pore-forming process is adopted in consideration of subway protection requirements. The drilling sequence adopts 'jump three drills one', and is carried out in three sequences. The construction of the support pile follows the flow production of the triaxial mixing pile, and 6 rotary drilling rigs are arranged. The technical key points of the support pile construction include:
(1) Before the drilling construction of the supporting pile in the karst cave area, in order to prevent the collapse or collapse of the pile hole wall, the specific gravity of slurry is greatly increased to increase the liquid column pressure, and a firm artificial hole wall is formed by repeatedly adding a filler consisting of clay and bentonite. The relative density of the mud during drilling should be controlled to be around 1.3g/m 3.
(2) And stopping construction of backfill holes for the karst cave with a large amount of slurry leakage. Mortar can be pumped into the karst cave according to the karst cave treatment mode, the mortar is filled to the position 1m above the karst cave, and drilling is performed again after the mortar is initially set.
(3) Increasing the height of the drill cylinder. The drilling barrel height is increased as much as possible when the conditions allow, and the height is not less than 1.5 times of the diameter of the pile. The top end of the protective cylinder is not smaller than 0.3m above the ground, clay is filled around the protective cylinder, and the protective cylinder is tamped layer by layer.
(4) The number of the slurry discharging holes is increased. The number of the slurry discharging holes is additionally arranged at the wall of the barrel drill, so that slurry can be quickly replenished when the liquid level in the slurry discharging holes is reduced.
(5) And (5) adopting a mine type drill bit for construction. The middle part of the mine type drill bit is cylindrical, and the upper part and the lower part are both round tables, so that the mine type drill bit is used for extruding and wall forming and tamping partial filler of a karst cave.
3. Construction of opposite-pulling prestress steel strand
(1) Excavation of foundation pit and steel strand grooves of connecting plate
According to the measuring lofting position, a steel strand groove and a connecting plate foundation pit are excavated by using an excavator or manually, and the excavation depth is lower than the design elevation by 5cm. Excavating the full section of the connecting plate foundation pit, and pouring a mortar cushion layer; the width of the bottom of the steel strand groove excavation is 0.3m, and the slope adopts 1:1 slope, laying fine sand cushion layers in the grooves corresponding to the positions of the steel strands after the substrate is manually leveled, and backfilling fine sand in the steel strand grooves.
(2) PVC sleeve mounting and fixing
The steel strand wires outsourcing 150mm diameter PVC pipe, accurate lofting before the PVC pipe installation to mark on the both ends support stake. The PVC pipeline is assembled according to the measurement mark hanging line section by section, and the installation length of the pipeline exceeds the surface of the crown beam by 10cm. And after the pipeline is installed, carrying out integral linear inspection, and temporarily fixing the positions of the steel strands at the middle positions of each section of the pipeline by adopting mortar. Fine sand is used for backfilling within 30cm above the pipeline, and plain soil can be used for backfilling the rest.
(3) Manufacture and installation of steel strand
And blanking the steel stranded wires, braiding the steel stranded wires, binding the steel stranded wires twice with 16# fine lead wires every 2m during the braiding, and smearing a layer of butter on the surfaces of the steel stranded wires. When the steel stranded wires pass through the PVC pipe, manual pushing is adopted, and the rope body is kept smooth when the steel stranded wires pass through the PVC pipe, so that the PVC pipe is prevented from being damaged.
(4) Crown beam and connecting plate construction
After the steel strand is installed, the crown beam of the pile top and the reinforced concrete connecting plate between the crown beam and the reinforced concrete connecting plate are constructed. During construction, the steel stranded wires and the PVC pipeline are protected, damage to the steel stranded wires and the PVC pipeline is avoided, and the steel stranded wires and the PVC pipeline are replaced if damaged.
(5) Tensioning and locking of prestressed steel strands
(1) And after the concrete strength of the crown beam and the connecting plate reaches the design requirement, starting to stretch the prestressed steel strand. The tensioning equipment is matched for use, and a pressure gauge reading-tensioning force relation curve is drawn through the calibration of a related certification authority and submitted to a supervision engineer as a formal file. Pressure gauges that are disassembled, serviced or subjected to a strong impact must be recalibrated.
(2) The prestressed steel strand tensioning adopts a construction method of single pre-tightening and re-grading integral tensioning. In order to ensure that the steel strands are straight and uniformly stressed, the single steel strand is pre-tensioned according to 10% of the design load before formal tensioning. The formal tensioning adopts integral tensioning, and is constructed according to three load levels of 300kN, 500kN and 800 kN. The load is applied uniformly, the loading rate is not more than 10% of the design stress per minute, the load is kept stable for 5 minutes after each stage of tensioning, and the elongation value of the steel strand is measured and recorded. If the actual elongation value is more than 10% or less than 5% of the theoretical elongation value, the stretching is stopped, and the stretching can be continued after the reason is found and remedial measures are taken. Stabilizing the pressure for 10-20 min to lock after reaching 100% of the design load.
(3) And monitoring the horizontal displacement of the pile top in real time in the tensioning process, and stopping tensioning and locking if the displacement is too large. And the locking force is monitored periodically in the foundation pit excavation construction process, and if the locking force is dissipated, the locking force needs to be timely supplemented and tensioned to the original locking value, so that the top constraint reliability of the support pile is ensured.
(4) And (3) in the earth excavation process, compensating and tensioning the prestress loss in time according to the monitoring data.
The invention provides a tunnel supporting isolation system, which comprises: the first support piles are respectively positioned at two sides of the tunnel; the second support piles are respectively positioned at one side of the first support pile away from the tunnel; the second support pile corresponds to the position of the first support pile; the tops of the first support piles and the second support piles are connected through connecting plates so as to form portal frame type support isolation pile structures on two sides of the tunnel respectively; the first support piles positioned on the same side of the tunnel are arranged in a row, and the tops of the first support piles are connected through crown beams; the second support piles positioned on the same side of the tunnel are arranged in a row, and the tops of the second support piles are connected through crown beams so as to effectively prevent disturbance of pile foundations on two sides of the tunnel and foundation pit construction processes on the tunnel and adjacent soil bodies; simultaneously through being provided with triaxial stirring stake wall between first support stake and second support stake, prevent the water loss in the karst cave for this scheme still is applicable to the construction protection in karst landform subway tunnel.
In the description of the present invention, it should be understood that the terms "middle," "length," "upper," "lower," "front," "rear," "vertical," "horizontal," "inner," "outer," "radial," "circumferential," and the like indicate an orientation or a positional relationship based on that shown in the drawings, merely for convenience of description and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the invention.
In the present invention, unless expressly stated or limited otherwise, a first feature "on" a second feature may be that the first and second features are in direct contact, or that the first and second features are in indirect contact via an intervening medium. The meaning of "a plurality of" means at least two, e.g., two, three, etc., unless explicitly defined otherwise.
In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
The above description is for the purpose of illustrating the embodiments of the present invention and is not to be construed as limiting the invention, but is intended to cover all modifications, equivalents, improvements and alternatives falling within the spirit and principles of the invention.
Claims (10)
1. A tunnel supporting insulation system, comprising:
the first support piles are respectively positioned at two sides of the tunnel;
the second support piles are respectively positioned at one side of the first support pile away from the tunnel; the second support pile corresponds to the position of the first support pile;
the tops of the first support piles and the second support piles are connected through connecting plates so as to form portal frame type support isolation pile structures on two sides of the tunnel respectively;
the first support piles positioned on the same side of the tunnel are arranged in a row, and the tops of the first support piles are connected through crown beams; and the second support piles positioned on the same side of the tunnel are arranged in a row, and the tops of the second support piles are connected through crown beams.
2. The tunnel support isolation system of claim 1, further comprising a triaxial mixing pile wall; the triaxial stirring stake wall is located between the first support stake and the second support stake.
3. The tunnel supporting and isolating system as claimed in claim 2, wherein the triaxial stirring pile wall adopts a triaxial stirring pile of lap joint type inserted section steel.
4. The tunnel support isolation system of claim 2, wherein the triaxial mixing pile wall is positioned adjacent to a side of the second support pile.
5. The tunnel support insulation system of claim 1, further comprising a screen; the hanging net is arranged on the second support pile.
6. A construction method of a tunnel supporting and isolating system, which is applied to the tunnel supporting and isolating system as claimed in any one of claims 1 to 5, comprising the following steps:
the specific gravity of the slurry is increased to increase the liquid column pressure before drilling construction; increasing the height of the drilling barrel, filling clay around the protection barrel, and tamping layer by layer; the number of slurry discharging holes is increased at the wall of the drill cylinder;
the construction is carried out by adopting a mine type drill bit during the drilling construction; forming an artificial pore wall by adding a filler consisting of clay and bentonite; adopting a rotary drilling and forming process, wherein the drilling sequence adopts 'three-jump drilling one', and is carried out in three sequences;
and excavating a connecting plate and a crown beam foundation pit after the construction of the support pile is completed, and constructing a crown beam on the top of the support pile and the connecting plate therebetween.
7. The method for constructing a tunnel supporting and isolating system according to claim 6, further comprising the steps of: and before the construction operation of the first support pile and the second support pile, simultaneously and symmetrically performing triaxial stirring pile wall construction on two sides of the tunnel, wherein the first support pile and the construction follow triaxial stirring pile wall construction line operation.
8. The method for constructing a tunnel supporting and isolating system according to claim 7, wherein the performing of the triaxial stirring pile construction comprises the steps of:
establishing a karst cave model to pre-judge construction conditions and a pre-cast construction scheme in advance, and timely processing when construction has problems;
optimizing construction process and construction parameters according to karst cave model data, and making a plan for handling slurry leakage hole collapse accidents;
and (5) carrying out triaxial stirring pile construction by using a triaxial stirrer.
9. The method for constructing a tunnel supporting and isolating system according to claim 8, wherein the step of preparing a plan for handling slurry leakage and hole collapse accidents comprises the following steps:
preparing a piece of stone and clay auxiliary materials; preparing a slurry pool and a water source and ensuring that the slurry has viscosity and gel rate; closely paying attention to the change of the mud level in the hole, supplementing the mud and lifting the drill once the mud is leaked, and throwing and filling the prepared auxiliary materials into the hole.
10. The method for constructing a tunnel supporting and insulating system according to any one of claims 6 to 9, further comprising the steps of: and stopping constructing backfill holes for the karst cave with slurry leakage, and re-drilling after the karst cave is initially set.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115369860A (en) * | 2022-09-30 | 2022-11-22 | 中建八局第二建设有限公司 | Construction method of super-long isolation pile close to subway |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115369860A (en) * | 2022-09-30 | 2022-11-22 | 中建八局第二建设有限公司 | Construction method of super-long isolation pile close to subway |
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