CN114703921B - A construction method for preventing sudden surge based on temporary bottom sealing structure - Google Patents

Abstract

The present invention relates to a construction method for preventing sudden surge based on a temporary bottom sealing structure, which at least comprises: before setting up a water-proof reinforcement structure, setting up at least one temporary bottom sealing structure preset to match the size of the shaft at a first position not affected by the confined water layer, and the distance between the first position and the confined water layer is not less than Among them, γ is the density of the impermeable layer, γ _ω is the density of water, and h is the height of the pressurized water head; a longitudinal reinforcement structure extending longitudinally downward to a specified depth is arranged between the first position and the second position, and a waterproof bottom sealing structure is arranged at the sixth position, and the longitudinal reinforcement structure and the waterproof bottom sealing structure are connected to form an integrated waterproof reinforcement structure so that the waterproof reinforcement structure cuts off the internal and external hydraulic connection, so as to increase the ability of the shaft bottom to resist the sudden surge of pressurized water; wherein, the distance between the first position and the sixth position is not less than 4m, the distance between the second position and the first position is not less than 1m, and the second position is above the water level line of the pressurized water.

Description

A construction method for preventing sudden surge based on temporary bottom sealing structure

This invention is a divisional application of an invention patent with application number 202010958047.4, application date September 11, 2020, and application name "A method for constructing a vertical shaft in a confined water layer based on non-drainage".

Technical Field

The invention relates to the technical field of shaft construction, and in particular to a construction method for preventing sudden surge based on a temporary bottom sealing structure.

Background technique

As my country is carrying out the South-to-North Water Diversion Project, the groundwater level in the northern region has gradually risen, which has brought certain difficulties to the current municipal subway construction. In order to protect water sources for green and environmentally friendly construction, the pumping of groundwater has been banned, which has further increased the difficulty of current shaft construction. At present, there are many construction methods for non-pressure water-rich strata, but there are relatively few excavation technologies for shafts in pressurized water strata.

The current prior art generally uses precipitation to excavate the confined water layer. For example, Chinese patent CN110387884A discloses a construction method for preventing sudden surges in ultra-deep foundation pits. The bottom of the foundation pit to be excavated is close to the confined water layer. The construction method includes: setting up an underground continuous wall around the area of the foundation pit to be excavated; using MJS to cast a water-proof reinforcement layer at the bottom of the underground continuous wall, and the peripheral edge of the water-proof reinforcement layer is in contact with the underground continuous wall; using MJS to cast a pressure-reducing reinforcement layer at the bottom of the foundation pit to be excavated above the water-proof reinforcement layer, and the peripheral edge of the pressure-reducing reinforcement layer is in contact with the underground continuous wall; excavating the foundation pit and correspondingly supporting the support structure. The present invention effectively solves the problem of the hidden danger of sudden surges of confined water during the excavation of ultra-deep foundation pits, and has little impact on the surrounding environment during construction, will not cause settlement of surrounding buildings, and can ensure construction quality and efficiency. Although this construction method can effectively prevent sudden surges, its reinforcement of the pit bottom is only one-time. This is effective for excavating foundation pits, but for subway construction that needs to penetrate the pressurized water layer, only one-time reinforcement of the pit bottom is completely insufficient.

Patent document CN 104912561B discloses a construction method for shield continuous crossing of shaft under high pressure water and complex strata conditions, which includes: step 1, end reinforcement; reinforcement of the soil at the end of the shaft, increase of the self-stability of the soil to ensure that no seepage occurs; step 2, breaking of the continuous wall of the portal and backfilling of the shaft; breaking of the portal concrete of the shaft from bottom to top, and removing the waste concrete in the shaft layer by layer, and backfilling the shaft with backfill materials; step 3, shield excavation and monitoring during the excavation process; step 4, grouting management behind the pipe segment; when the shield machine passes through the shaft to exit and enter the hole, the shield tail strengthens the synchronous grouting before exiting the hole, and uses radar to check the wall thickness grouting effect, and determines whether to perform secondary grouting according to the wall thickness grouting effect. Although the invention can reduce the danger of the shield to the high pressure water and complex strata when it passes through the shaft. However, the invention still uses the dewatering well to dewater and then excavates the shaft of the pressure water layer, which does not fundamentally change the shaft construction method.

The present invention aims to make up for the shortcomings of the existing vertical shaft construction technology, provide a new method for solving the problem of vertical shaft excavation in pressurized water strata, and solve the problem of water gushing, collapse and instability caused by excessive deformation of the shaft wall due to the head pressure in the stratum.

Patent document CN 104895570B discloses a method for reinforcing and excavating a subway shaft in a soft and water-rich stratum, comprising the following steps: step 1), vertical reinforcement; step 2), vertical partial excavation; step 3), lateral reinforcement; step 4), lateral expansion; step 5), shaft lining; step 6), deformation monitoring; step 7), repeating steps 1) to 6), excavating to the design elevation; step 8), casting the bottom plate, after excavating to the design elevation, casting the bottom of the shaft. The so-called "excavation method" adopted by the invention first requires the construction of an integral reinforcement structure, and the subsequent excavation process is also based on the reinforcement structure, that is, excavating and shaving off excess reinforcement material on the reinforcement structure to form a shaft structure. The technical solution as a whole relies on the overall construction to form a reinforcement structure, and then excavating excess reinforcement material to form a shaft side wall structure. The invention consumes more reinforcement materials to form the overall structure of the reinforcement body. The formed reinforcement body structure is not completely used for reinforcement. Most of the materials in the middle must be removed to form the shaft structure, which obviously causes greater waste. In contrast, the longitudinal reinforcement structure of the shaft of the present invention is not formed by "removing the integral reinforcement material".

In addition, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the inventor studied a large number of documents and patents when making the present invention, but due to space limitations, not all details and contents are listed in detail. However, this does not mean that the present invention does not have the characteristics of these prior arts. On the contrary, the present invention already has all the characteristics of the prior art, and the applicant reserves the right to add relevant prior art to the background technology.

Summary of the invention

In view of the shortcomings of the prior art, the present invention provides a method for constructing a vertical shaft in a confined water layer without drainage, characterized in that the method at least comprises:

At least one temporary bottom sealing structure preset to match the size of the shaft is arranged at a first position not affected by the confined water layer,

A transverse horizontal reinforcement structure extending along the periphery of the shaft wall within a specified range is arranged at a second position above the first position;

Below the second position, longitudinal reinforcement structures distributed along the side wall of the shaft and water-proof reinforcement structures connected to the longitudinal reinforcement structures are respectively arranged to form a waterproof reinforcement layer of the shaft contour.

After the temporary bottom sealing structure is broken, a vertical shaft is excavated to a preset distance that does not penetrate the water-proof reinforcement structure. The vertical shaft is excavated in sections by cyclically arranging the temporary bottom sealing structure, the transverse horizontal reinforcement structure and the waterproof reinforcement layer to form a vertical shaft structure that penetrates the pressurized water layer.

The present invention uses cyclic segmented construction to ensure that the side walls and bottom of each excavated shaft section are waterproofly reinforced horizontally, vertically and bottom-sealed, making the excavation process simple and safe without worrying about sand gushing caused by water pressure in the pressurized water layer.

Preferably, the method for forming a waterproof reinforcement layer of a shaft profile comprises:

At least one layer of longitudinal grouting steel pipes obliquely distributed along the side wall of the shaft is arranged between the first position and the second position, and the longitudinal grouting steel pipes are grouted obliquely downward in a deep hole grouting manner to form the longitudinal reinforcement structure distributed along the side wall of the shaft. The longitudinal reinforcement structure of the present invention can form a waterproof reinforcement layer outside the side wall of the shaft, and the oblique deep hole grouting can make the slurry solidify along the side wall of the shaft, which is conducive to the grouting steel pipes at different angles to be poured in layers.

Preferably, the method for forming a waterproof reinforcement layer of a shaft profile further comprises:

At a sixth position below the first position, vertical deep hole grouting and/or inclined deep hole grouting are performed in a backward grouting manner to form a grouting thickness not less than the thickness of the impermeable layer. The waterproof reinforcement structure is as follows: _H1 is the thickness of the impermeable layer after the shaft is excavated, γ is the weight of the impermeable layer, _γω is the weight of water, and h is the height of the pressure water head. Through scientific calculation and setting, the waterproof bottom sealing structure of the shaft can resist the water pressure of the pressure water layer and prevent the water pressure from impacting the excavated sediment in the shaft.

Preferably, the method further comprises: horizontally arranging transverse grouting steel pipes including long steel pipes and short steel pipes along the side wall of the shaft at the second position, wherein the long steel pipes and the short steel pipes are arranged at intervals in a staggered manner of length, so that the transverse grouting steel pipes are cast in a horizontal deep hole grouting manner to form a transverse horizontal reinforcement structure. By arranging the transverse horizontal staggered long and short grouting steel pipes, slurry siltation in the same range can be avoided, which is more conducive to uniform transverse slurry distribution.

Preferably, the method further comprises: when the transverse cross-sectional profile of the shaft is a rectangle, at least one long steel pipe and at least one short steel pipe at the intersection ends of the two intersecting sides are arranged in a diffuse manner in a manner inclined with the sides, wherein the two long steel pipes at the two intersection ends are arranged adjacent to each other. By arranging adjacent long steel pipes at right angles, the horizontal extension range of the slurry at the right angle part can be made the same as the horizontal extension range of other parts, thereby avoiding the defect of insufficient horizontal reinforcement at the right angle position of the shaft.

Preferably, during the process of excavating downward along the shaft excavation surface, at least one primary lining structure is provided on the inner wall of the shaft. Providing the primary lining structure is beneficial to supporting the side wall of the shaft.

Preferably, the method further comprises: when the shaft is excavated in sections to a preset depth in a cyclic manner, a permanent bottom sealing structure is set at the bottom of the shaft by pouring concrete. A permanent bottom sealing structure that can be connected to the side wall of the shaft is set to make the overall shaft structure complete. In the process of penetrating the confined water layer, it is not necessary to set up additional precipitation wells for pumping and draining. Only the residual water in the constructed shaft needs to be pumped and drained, which reduces the workload of pumping and draining and also protects groundwater resources.

The present invention also provides a circulating type confined water layer shaft construction method, characterized in that the method at least comprises:

A temporary bottom sealing structure is set up at the first location not affected by the confined water layer.

A transverse horizontal reinforcement structure extending along the periphery of the shaft wall is arranged at a second position higher than the first position by means of horizontal deep hole grouting.

A longitudinal reinforcement structure surrounding the side wall of the shaft is formed by at least one layer of longitudinal grouting steel pipes arranged between the first position and the second position in a manner of inclined deep hole grouting.

A water-proof reinforcement structure which is circumferentially connected to the longitudinal reinforcement structure as a whole is arranged at a sixth position lower than the first position by a backward grouting method.

The shaft construction method of the present invention pre-reinforces the pre-excavated section of the shaft to block the pressurized water layer, and then excavates in the reinforced section to gradually increase the depth of the shaft, so that each excavated section is in a waterproof reinforced protective layer, thereby avoiding the influence of water pressure of the pressurized water layer.

Preferably, at least two layers of longitudinal grouting steel pipes are arranged between the first position and the second position for grouting downwardly along the side wall of the shaft, the orthographic projections of the two layers of longitudinal grouting steel pipes on the same horizontal plane are relatively displaced, and the inclination angle of the layer of longitudinal grouting steel pipes at a lower position is smaller than the inclination angle of the layer of longitudinal grouting steel pipes at a higher position. The setting of different angles is conducive to grouting the slurry of the longitudinal grouting steel pipes in different circumferential ranges outside the side wall of the shaft, and the longitudinal reinforcement structure formed is uniform and stronger.

Preferably, three layers of longitudinal grouting steel pipes are arranged between the first position and the second position for grouting obliquely downwardly along the side wall of the shaft, the first layer of grouting steel pipes are arranged at a first angle along the circumference of the side wall of the shaft at the third position between the first position and the second position, the second layer of grouting steel pipes are arranged at a second angle along the circumference of the side wall of the shaft at the fourth position between the first position and the second position, and the third layer of grouting steel pipes are arranged at a third angle along the circumference of the side wall of the shaft at the fifth position between the first position and the second position, and when the heights of the third position, the fourth position and the fifth position are successively reduced, the first angle, the second angle and the third angle are successively reduced, and the lengths of the first layer of grouting steel pipes, the second layer of grouting steel pipes and the third layer of grouting steel pipes are successively increased. The arrangement of three layers of grouting steel pipes is conducive to the rapid completion of grouting of the longitudinal reinforcement structure, and the grouting is uniform without grouting dead angles.

The present invention also provides a construction method for preventing sudden surge based on a temporary bottom sealing structure, the method comprising at least the following steps: before setting up the water-proof reinforcement structure, setting up at least one temporary bottom sealing structure preset to match the size of the shaft at a first position not affected by the confined water layer, the distance between the first position and the confined water layer being not less than Among them, γ is the density of the impermeable layer, γ _ω is the density of water, and h is the height of the confined water head;

A longitudinal reinforcement structure extending longitudinally downward to a specified depth is provided between the first position and the second position, and a waterproof bottom sealing structure is provided at the sixth position, and the longitudinal reinforcement structure and the waterproof bottom sealing structure are connected to form an integrated waterproof reinforcement structure so that the waterproof reinforcement structure isolates the internal and external hydraulic connection, so as to increase the ability of the shaft bottom to resist the sudden surge of pressurized water;

Among them, the distance between the first position and the sixth position is not less than 4m, the distance between the second position and the first position is not less than 1m, and the second position is above the water level of the pressurized water.

Preferably, the method further includes: after setting up the water-proof reinforcement structure, breaking down the temporary bottom sealing structure, and excavating the vertical shaft to a preset distance that does not penetrate the water-proof reinforcement structure, and excavating the vertical shaft in sections by cyclically setting up the temporary bottom sealing structure, the transverse horizontal reinforcement structure and the waterproof reinforcement layer to form a vertical shaft structure that penetrates the pressurized water layer.

Preferably, the method of setting up a longitudinal reinforcement structure between the first position and the second position includes: setting up at least one layer of longitudinal grouting steel pipes obliquely distributed along the side wall of the shaft, and the longitudinal grouting steel pipes are grouted obliquely downward in a deep hole grouting manner to form the longitudinal reinforcement structure distributed along the side wall of the shaft.

Preferably, at the second position, transverse grouting steel pipes including long steel pipes and short steel pipes are horizontally arranged along the side wall of the shaft, and the long steel pipes and short steel pipes are arranged at intervals in a staggered manner of long and short, so that the transverse grouting steel pipes are cast by horizontal deep hole grouting to form a transverse horizontal reinforcement structure.

Preferably, the method also includes: setting a transverse horizontal reinforcement structure extending along the periphery of the shaft wall to a specified range at a second position above the first position to perform transverse horizontal reinforcement on the outer periphery of the shaft, and the transverse horizontal reinforcement structure forms a horizontal slurry stop wall at the upper part of the excavation area, thereby preventing the formation of water channels between various layers.

Preferably, the method further comprises: after setting the temporary bottom sealing structure and before setting the water-proof reinforcement structure, reinforcing and forming the transverse horizontal reinforcement structure by means of horizontal deep hole grouting within a range of 3 m around the shaft wall.

Preferably, when the transverse cross-sectional profile of the shaft is a rectangle, at least one long steel pipe and at least one short steel pipe at the intersection ends of the two sides of the transverse horizontal reinforcement structure are arranged in a diffuse manner in an inclined manner to the edges, wherein the two long steel pipes at the two intersection ends are adjacent to each other.

Preferably, the method for providing the longitudinal reinforcement structure further comprises:

The longitudinal grouting steel pipe includes a first layer of grouting steel pipes arranged at a third position, a second layer of grouting steel pipes arranged at a fourth position, and a third layer of grouting steel pipes arranged at a fifth position.

The setting heights of the first layer of grouting steel pipes, the second layer of grouting steel pipes and the third layer of grouting steel pipes are gradually reduced, and deep hole grouting is performed in an inclined manner around the outer periphery of the shaft at the respective heights;

The first layer of grouting steel pipes is arranged at a first angle along the circumference of the shaft side wall and deep hole grouting is performed;

The second layer of grouting steel pipes is arranged at a second angle along the circumference of the shaft side wall and deep hole grouting is performed;

The third layer of grouting steel pipes is arranged at a third angle along the circumference of the shaft side wall and deep hole grouting is performed;

The first angle, the second angle and the third angle become smaller successively, so that during the grouting process, the slurry is grouted to the side wall of the shaft in a transverse layered manner, and the slurry forms a transversely thickened grouting from the inside to the outside of the side wall of the shaft, forming a longitudinal reinforcement structure reaching a preset thickness and a preset longitudinal depth.

Preferably, the method for setting up a water-proof reinforcement structure also includes: performing deep hole grouting with a bottom grouting steel pipe at an angle of 3-5° downward at a distance of 1.5m from the inner wall of the shaft, thereby forming a partial bottom structure on the bottom side of the shaft that can be connected to the longitudinal reinforcement structure, and connecting the longitudinal reinforcement structure with the water-proof reinforcement structure to form a complete closed reinforcement body.

Preferably, during the process of excavating downward along the shaft excavation surface, at least one primary lining structure is arranged on the inner wall of the shaft; after the shaft is excavated to a preset depth, a permanent bottom sealing structure is arranged on the shaft bottom plate.

Beneficial technical effects of the present invention:

As described above, the present invention adopts the method of pre-reinforcement followed by excavation, which can effectively prevent the problem of water and sand gushing caused by pressurized water during shaft construction, solve the safety hazards of shaft water-carrying construction, and prevent safety instability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a logical schematic diagram of the construction method of the present invention;

Fig. 2 is a schematic diagram of the principle of the present invention before construction;

FIG3 is a schematic longitudinal section view of a shaft structure of the present invention;

FIG4 is a schematic diagram of the top view of the vertical shaft of the present invention;

FIG5 is a schematic longitudinal cross-sectional view of the shaft of the present invention in an excavation state;

FIG6 is a schematic longitudinal section view of a primary lining structure of a shaft according to the present invention;

7 is a schematic top view of the structure of the permanent bottom sealing structure of the shaft according to the present invention;

FIG8 is a schematic structural diagram of the deep hole casting of the vertical shaft longitudinal reinforcement structure of the present invention.

Reference numerals list

1: Temporary bottom sealing structure; 2: Transverse horizontal reinforcement structure; 3: Longitudinal reinforcement structure; 4: Waterproof reinforcement structure; 5: Primary lining structure; 6: Permanent bottom sealing structure; 7: First angle brace; 8: Second angle brace; 10: Waterproof reinforcement layer; 11: Pressure water layer; 20: Transverse grouting steel pipe; 30: Longitudinal grouting steel pipe; 31: First layer grouting steel pipe; 32: Second layer grouting steel pipe; 33: Third layer grouting steel pipe; 40: Bottom sealing grouting steel pipe; A: Vertical shaft.

Detailed ways

The following is a detailed description with reference to the accompanying drawings.

The present invention provides a method for constructing a vertical shaft in a confined water layer without drainage, which adopts a method of pre-reinforcement followed by excavation for continuous operation, thereby achieving the vertical shaft passing through the confined water layer and avoiding the phenomenon of water and sand gushing caused by the action of the confined water.

The principle of the present invention is as follows: as shown in FIG2 , water-proof bottom reinforcement is achieved through artificial grouting, an artificial water-proof reinforcement structure is formed at the bottom of the shaft, and a closed longitudinal reinforcement structure is formed within the periphery of the shaft to resist water pressure.

In trenchless operation, γH ₁ = γ _ω h;

Among them, _H1 is the thickness of the impermeable layer after shaft excavation, γ is the density of the impermeable layer, _γω is the density of water, and h is the height of the pressure water head.

The thickness of the impermeable layer after foundation pit excavation is

When the confined water layer is deeply reinforced, the rock and soil density will increase significantly, that is, γ will increase, achieving The condition that no sudden surge occurs at the bottom of the pit can be met. The continuous excavation of the shaft is achieved through repeated cycles of bottom sealing and reinforcement structure construction operation steps.

The present invention provides a method for constructing a vertical shaft in a water-confined layer without drainage, as shown in Figure 1, comprising steps S1 to S8. The present invention can also be a circulating method for constructing a vertical shaft in a water-confined layer.

S1: Set up a temporary bottom sealing structure for the shaft.

A temporary bottom sealing structure 1 is provided at a first position above the influence stratum of the pressure water layer 11. The distance between the first position and the pressure water layer is not less than

Preferably, an I-beam is used to set a temporary bottom sealing structure whose horizontal plane intersects the central axis of the shaft. Optimally, the horizontal plane of the temporary bottom sealing structure tends to be relatively perpendicular to the central axis of the shaft.

For example, the temporary bottom sealing structure 1 is a reinforcement structure reinforced by using I-beams at the horizontal plane of the shaft. The first position is a position at a vertical distance of not less than 1.5 m from the stratum affected by the confined water layer.

Preferably, the method for making the temporary bottom sealing structure 1 is: using I-beam as a skeleton, spraying premixed concrete to complete the temporary bottom sealing structure of the shaft. For example, the thickness of the temporary bottom sealing structure 1 is 0.6m. The thickness of the temporary bottom sealing structure is not limited to 0.6m, and can also be other thicknesses that are easy to excavate.

As shown in Figure 4, the I-beam frame includes at least one first angle brace 7, at least one second angle brace 8 and other steel pipes arranged at the angle of the shaft. The first angle brace is a concrete angle brace, and the second angle brace is an I-beam angle brace, both of which are used to support the I-beam frame. For example, the cross-sectional shape of the shaft is a rectangle with four corners. On the horizontal plane where the temporary bottom cover structure 1 is arranged, a first angle brace 2 is arranged at one corner, and second angle braces are arranged at the remaining three corners.

S2: Set up transverse horizontal reinforcement structure.

A horizontal reinforcement structure 2 for horizontal reinforcement is arranged at a second position above the first position where the temporary bottom sealing structure 1 is located, so as to realize horizontal reinforcement of the outer periphery of the shaft. The advantage of such arrangement is that the present invention performs horizontal deep hole grouting at the second position above the elevation position of the temporary shaft bottom sealing structure, and forms a horizontal grouting wall at the upper part of the excavation area, so as to prevent the formation of water channels between various layers and avoid the collapse of the upper sand and soil caused by the migration of water.

Preferably, the distance between the second position and the first position is not less than 1 m. Preferably, the transverse horizontal reinforcement structure 2 is reinforced by grouting within 3 m around the shaft wall.

Preferably, the distance between the second position and the temporary packaging structure is 1.2 m, wherein the second position is above the water level of the pressurized water.

As shown in FIG4 , the transverse horizontal reinforcement structure 2 is formed by a plurality of transverse grouting steel pipes 20 in a deep hole grouting manner. The transverse grouting steel pipes 20 include long steel pipes and short steel pipes. The transverse horizontal reinforcement structure 2 is deep hole grouting in batches. In the first batch of deep hole grouting, chemical double liquid slurry is used for grouting and water stopping; in the second batch, double liquid cement slurry is used for reinforcement.

Preferably, as shown in FIG4 , at the periphery of the vertical shaft at the second position, the long steel pipes and the short steel pipes are distributed in a plum blossom shape with the vertical shaft as the center. The longitudinal and transverse spacings between the long steel pipes and the short steel pipes are 30-40 cm. The length of the long steel pipe is 2-2.5 m, and the length of the short steel pipe is 1.5-2 m. Among them, for the vertical shaft with a rectangular cross section, at least one long steel pipe and at least one short steel pipe arranged at one end of the long side and/or short side of the rectangle are inclined in the direction of the angle bend, so that the long steel pipes and short steel pipes distributed near the right angle of the vertical shaft are distributed in a plum blossom shape or radial shape around the right angle. Preferably, for the vertical shaft with a rectangular cross section, the long steel pipes are arranged at both ends of each side of the rectangle, so that the long steel pipes respectively arranged on the two right-angle sides of each right angle are adjacent and in opposite inclination directions. The long steel pipe or short steel pipe not close to the right angle is arranged perpendicularly to the edge of the vertical shaft.

S3: A longitudinal reinforcement structure 3 extending longitudinally downward to a specified depth is provided at at least one position between the first position and the third position on the periphery of the shaft.

Preferably, the longitudinal reinforcement depth is 6 m extending vertically downward from the third position. Preferably, the transverse reinforcement range of the longitudinal reinforcement structure 3 is 2 m.

Preferably, a longitudinal reinforcement structure 3 arranged on the periphery of the shaft is formed by deep hole grouting along the side wall of the shaft A. The longitudinal reinforcement structure 3 can make the grouting radius range of each grouting point overlap each other, forming a reinforcement body on the side wall around the shaft to resist the pressure of the confined water layer.

Preferably, deep hole grouting is performed along the side wall of the shaft at a third position, a fourth position and/or a fifth position above the elevation position of the temporary bottom sealing structure 1 using a longitudinal grouting steel pipe 30 at an inclined angle, thereby forming a longitudinal reinforcement structure 3 to achieve vertical reinforcement of the side wall of the shaft.

The longitudinal grouting steel pipe 30 includes a first layer of grouting steel pipe 31 set at the third position, a second layer of grouting steel pipe 32 set at the fourth position, and a third layer of grouting steel pipe 33 set at the fifth position. The setting heights of the first layer of grouting steel pipe 31, the second layer of grouting steel pipe 32, and the third layer of grouting steel pipe 33 are gradually reduced, and deep hole grouting is performed in an inclined manner around the outer circumference of the shaft at the respective position heights.

Any one, any two or all of the first layer of grouting steel pipes 31, the second layer of grouting steel pipes 32 and the third layer of grouting steel pipes 33 can be set between the first position and the second position. The intervals between the third position, the fourth position and the fifth position can be set as needed, and the present invention does not limit this.

The first layer of grouting steel pipes at the third position are arranged at a first angle along the circumference of the shaft side wall and deep hole grouting is performed to form a partial or complete longitudinal reinforcement structure 3 for longitudinally reinforcing the shaft side wall.

The second layer of grouting steel pipes at the fourth position are arranged at a second angle along the circumference of the shaft side wall and deep hole grouting is performed to form a partial or complete longitudinal reinforcement structure 3 for longitudinally reinforcing the shaft side wall.

The third layer of grouting steel pipes at the fifth position are arranged at a third angle along the circumference of the shaft side wall and deep hole grouting is performed to form a partial or complete longitudinal reinforcement structure 3 for longitudinally reinforcing the shaft side wall.

If the first angle, the second angle and the third angle are the same, during the grouting process, the slurry is easy to accumulate in the same horizontal range, which is not conducive to the uniform pouring of the slurry. In the present invention, when the heights of the third position, the fourth position and the fifth position are successively reduced, the first angle, the second angle and the third angle are successively reduced, and the lengths of the first layer of grouting steel pipes, the second layer of grouting steel pipes and the third layer of grouting steel pipes are successively increased. The setting of gradually decreasing angles is conducive to grouting the slurry to the side wall of the shaft in a horizontal layered manner during the grouting process, and is conducive to the slurry forming a horizontally thickened grouting from the inside to the outside of the side wall of the shaft, forming a longitudinal reinforcement structure 3 reaching a preset thickness and a preset longitudinal depth.

Preferably, the first layer of grouting steel pipes 31, the second layer of grouting steel pipes 32 and/or the third layer of grouting steel pipes 33 are not all distributed in the same longitudinal plane. That is, the orthographic projections of the second layer of grouting steel pipes and the first layer of grouting steel pipes on the same horizontal plane are staggered and do not intersect each other. The orthographic projections of the second layer of grouting steel pipes and the third layer of grouting steel pipes on the same horizontal plane are staggered and do not intersect each other. For example, they are arranged in a layered staggered manner according to the petals.

Based on the combined effect of different heights, different angles and mutually staggered settings of the first layer of grouting steel pipes 31, the second layer of grouting steel pipes 32 and the third layer of grouting steel pipes 33, the first layer of grouting steel pipes 31, the second layer of grouting steel pipes 32 and the third layer of grouting steel pipes 33 form an inverted plum blossom distribution shape with the shaft as the center and the grouting steel pipes staggered in layers. The first layer of grouting steel pipes 31, the second layer of grouting steel pipes 32 and the third layer of grouting steel pipes 33 perform plum blossom grouting each time when grouting the side wall of the shaft, which can ensure that the grouting influence radii overlap with each other to form a closure, and avoid the appearance of grouting gaps.

The following is one implementation of the longitudinal reinforcement structure 3 of the present invention.

Preferably, the third position is 70 cm above the first position of the temporary bottom structure 1. The fourth position is 40 cm above the first position of the temporary bottom structure 1. The fifth position is 20 cm above the first position of the temporary bottom structure 1. Such interval arrangement is conducive to uniform grouting of the grouting steel pipes at each position in the longitudinal direction, forming a longitudinal reinforcement structure 3 with uniform thickness.

Preferably, the first layer of grouting steel pipes 31 at the third position are at a first angle of 40° to 50° with the shaft side wall at the third position and are arranged circumferentially along the shaft side wall, so as to perform 40° to 50° deep hole grouting. The length of the first layer of grouting steel pipes 31 is 2 to 2.5 m. The first transverse spacing between the first sub-grouting steel pipes 61 is 50 to 60 cm.

The second layer of grouting steel pipe 32 is at a second angle of 20 to 25° with the shaft side wall at the fourth position and is arranged circumferentially along the shaft side wall, so as to perform 20 to 25° deep hole grouting. The length of the second layer of grouting steel pipe 32 is 4 to 4.5 m. The second lateral spacing between the second layer of grouting steel pipes 32 is 50 to 60 cm. On the horizontal projection plane, the second layer of grouting steel pipe 32 is staggered relative to the first layer of grouting steel pipe 31. That is, the second layer of grouting steel pipe 32 and the first layer of grouting steel pipe 11 are staggered in a plum blossom shape.

The third layer of grouting steel pipe 33 is arranged at a third angle of 10° to 15° with the side wall of the shaft at the fifth position, so as to perform deep hole grouting at 10° to 15°. The length of the third layer of grouting steel pipe 33 is 6 to 7m. The second transverse spacing between the third layer of grouting steel pipes 33 is 50 to 60cm. On the horizontal projection plane, the third layer of grouting steel pipe 33 is staggered relative to the second layer of grouting steel pipe 32. That is, the third layer of grouting steel pipe 33 and the second layer of grouting steel pipe 32 are staggered in a plum blossom shape.

S4: Set up a waterproof bottom sealing structure 4.

As shown in Figures 3 to 6, vertical deep hole grouting is performed at the sixth position below the first position of the temporary bottom sealing structure 1 to form a water-proof reinforcement structure 4 that can be connected to the longitudinal reinforcement structure 3 as a whole. Among them, the distance between the first position and the sixth position is not less than 4m. Preferably, the sixth position is 4.5m below the first position. The present invention sets a water-proof reinforcement structure at the sixth position, which can increase the ability of the pit bottom to resist the sudden surge of pressurized water, thereby forming a closed reinforcement body on the outer wall of the shaft to separate the internal and external hydraulic connections.

As shown in Figure 8, the present invention adopts a backward grouting method to control the grouting position. There are two deep hole grouting methods at the sixth position:

The first method is: the bottom grouting steel pipe 40 is grouting vertically downward, and the grouting depth ranges from 4.5 to 6 m.

The second method is: deep hole grouting is performed by a bottom grouting steel pipe 40 at a downward inclination of 1.5m from the inner wall of the shaft, with an inclination angle of 3-5°, which is conducive to forming a partial bottom structure on the bottom side of the shaft that can be connected to the longitudinal reinforcement structure 3, and connecting the longitudinal reinforcement structure 3 with the water-proof reinforcement structure 4 to form a complete closed reinforcement body.

The water-proof reinforcement structure 4 of the present invention is reinforced with the longitudinal reinforcement structure 3 of the lateral shaft wall to form a closed reinforcement body, which is a key step of the grouting closure of the present invention. Preferably, the grouting pressure of the bottom grouting steel pipe 40 is 0.5-1MPa. The water-proof reinforcement structure 4 is reinforced with double-liquid cement slurry, and the grouting depth is 1.5m. The grouting holes of the bottom grouting steel pipe 40 are spaced 1.5m in the vertical and horizontal directions.

Through steps S1 to S4, the longitudinal reinforcement structure 3 is connected with the water-proof reinforcement structure 4 to form a complete shaft-shaped waterproof reinforcement body, which can resist the water pressure of the confined water layer. The soil in the shaft will not be pressed by the water pressure of the confined water layer during excavation, and water can only penetrate slowly, effectively avoiding the problem of water gushing and quicksand caused by the pressure of the confined water layer on the excavation of the stratum.

S5: Destroy the temporary bottom cover structure 1.

The temporary bottom sealing structure 1 is removed to prepare for the excavation of the shaft.

S6: Vertical excavation of shaft A.

The vertical shaft excavation is carried out by the inverted shaft wall method. During the excavation process, the surface water in the shaft is pumped out. As shown in Figure 6, the initial lining structure 5 of the vertical shaft is constructed every 50 cm.

S7: After excavating 4 m, steps S2 to S6 are performed again until the excavation passes through the confined water stratum.

After breaking down the temporary bottom sealing structure 1, excavation is carried out in sections when passing through the confined water stratum. After each section is excavated, reinforcement is carried out according to steps S2-S6, and excavation is repeated until the construction of the confined water stratum shaft is completed.

S8: After the shaft is excavated to a preset depth, a permanent bottom sealing structure 6 is set on the shaft bottom plate.

Specifically, as shown in FIG. 7 , an I-beam is used as a steel skeleton, and concrete is poured to seal the bottom plate of the shaft, thereby forming a permanent bottom sealing structure 6 .

The method for constructing a vertical shaft in a pressurized water layer without drainage of the present invention adopts a method of excavation followed by pre-reinforcement, which can effectively prevent the problem of water and sand gushing caused by the action of pressurized water during the vertical shaft construction process, solve the safety hazard of vertical shaft water-carrying construction, and prevent safety instability.

It should be noted that the above-mentioned specific embodiments are exemplary, and those skilled in the art can come up with various solutions inspired by the disclosure of the present invention, and these solutions also belong to the disclosure scope of the present invention and fall within the protection scope of the present invention. Those skilled in the art should understand that the present invention specification and its drawings are illustrative and do not constitute a limitation on the claims. The scope of protection of the present invention is defined by the claims and their equivalents. The present invention specification contains multiple inventive concepts, such as "preferably", "according to a preferred embodiment" or "optionally", which means that the corresponding paragraph discloses an independent concept, and the applicant reserves the right to file a divisional application based on each inventive concept.

Claims (8)

1. The construction method for preventing surging based on the temporary back cover structure is characterized by at least comprising the following steps:

before arranging the waterproof reinforcement structure (4), arranging at least one temporary bottom sealing structure (1) which is preset to be matched with the size of the vertical shaft at a first position which is not influenced by the pressure-bearing water layer, wherein the distance between the first position and the pressure-bearing water layer is not less than ; Wherein/>Is the water impermeable layer weight,/>Is the gravity of water,/>Is the height of the pressure-bearing water head;

The second position is arranged above the first position, a transverse horizontal reinforcing structure (2) extending along the periphery of the shaft wall within a specified range is arranged at the second position so as to transversely and horizontally reinforce the periphery of the shaft, and the transverse horizontal reinforcing structure (2) forms a horizontal slurry stopping wall at the upper part of an excavation area, so that the formation of water channels between various floors is prevented;

arranging a longitudinal grouting steel pipe (30) between the first position and the second position to form a longitudinal reinforcing structure (3) which longitudinally extends downwards to a specified depth and is distributed along the side wall of the vertical shaft, and carrying out bottom hole vertical deep hole grouting at a sixth position below the first position of the temporary bottom sealing structure (1) to form a waterproof reinforcing structure (4) which can be connected with the longitudinal reinforcing structure (3) into a whole, wherein the waterproof reinforcing structure (4) and the longitudinal reinforcing structure (3) form a waterproof reinforcing layer of the profile of the vertical shaft, so that the sealing reinforcing body formed by reinforcing the waterproof reinforcing structure (4) and the longitudinal reinforcing structure (3) cuts off internal and external hydraulic connection, and the capacity of the bottom of the vertical shaft pit for resisting pressure water surge is increased;

After the waterproof reinforcement structure (4) is arranged, excavating a vertical shaft in a sectional manner until a preset distance which does not penetrate through the waterproof reinforcement structure (4) is reserved under the condition that the temporary bottom sealing structure (1) is broken, and excavating the vertical shaft in a sectional manner in a mode that the temporary bottom sealing structure (1), the transverse horizontal reinforcement structure (2) and the waterproof reinforcement layer are circularly arranged so as to form a vertical shaft structure penetrating through the bearing water layer;

the distance between the first position and the sixth position is not smaller than 4m, the distance between the second position and the first position is not smaller than 1m, and the second position is located above the water level line of the pressure-bearing water.

2. The construction method for preventing surging based on a temporary back cover structure according to claim 1, wherein the method for disposing the longitudinal reinforcement structure (3) between the first position and the second position comprises: at least one layer of longitudinal grouting steel pipes (30) which are distributed along the side wall of the vertical shaft in an inclined way is arranged,

The longitudinal grouting steel pipes (30) are grouted obliquely downwards in a deep hole grouting mode to form the longitudinal reinforcing structures (3) distributed along the side wall of the vertical shaft.

3. The construction method for preventing surging based on the temporary back cover structure according to claim 2, wherein,

A transverse grouting steel pipe (20) comprising a long steel pipe and a short steel pipe is horizontally arranged along the side wall of the vertical shaft at a second position, the long steel pipe and the short steel pipe are arranged at intervals in a long-short staggered mode,

And the transverse grouting steel pipe (20) is poured in a horizontal deep hole grouting mode to form a transverse horizontal reinforcing structure (2).

4. The construction method for preventing surging based on the temporary back cover structure according to claim 2, wherein the method further comprises:

After the temporary bottom sealing structure (1) is arranged and before the waterproof reinforcing structure is arranged, the transverse horizontal reinforcing structure (2) is reinforced and formed in a horizontal deep hole grouting mode within the range of 3m along the periphery of the shaft wall.

5. The construction method for preventing surging based on the temporary back cover structure according to claim 2, wherein,

Under the condition that the profile of the transverse cross section of the vertical shaft is rectangular, at least one long steel pipe and at least one short steel pipe at the intersecting ends of two intersecting sides of the transverse horizontal reinforcing structure (2) form diffusion arrangement in a manner of inclining to the sides, wherein the two long steel pipes at the two intersecting ends are adjacently arranged.

6. A construction method for preventing surging based on a temporary back cover structure according to claim 3, wherein the method for providing the longitudinal reinforcement structure (3) further comprises:

the longitudinal grouting steel pipe (30) comprises a first layer of grouting steel pipe (31) arranged at a third position, a second layer of grouting steel pipe (32) arranged at a fourth position and a third layer of grouting steel pipe (33) arranged at a fifth position,

The arrangement heights of the first layer grouting steel pipe (31), the second layer grouting steel pipe (32) and the third layer grouting steel pipe (33) are gradually reduced, and deep hole grouting is respectively carried out in a manner of inclining around the periphery of the vertical shaft at the positions;

The first layer grouting steel pipe (31) is arranged at a first angle along the circumferential direction of the side wall of the vertical shaft and is used for deep hole grouting;

the second layer grouting steel pipes (32) are arranged at a second angle along the circumferential direction of the side wall of the vertical shaft and are used for deep hole grouting;

The third-layer grouting steel pipe (33) is circumferentially arranged at a third angle along the side wall of the vertical shaft and is used for deep hole grouting;

The first angle, the second angle and the third angle are sequentially reduced, so that in the grouting process, the slurry is used for grouting the side wall of the vertical shaft in a transverse layering mode, and the slurry forms transverse thickened grouting on the side wall of the vertical shaft from inside to outside, so that a longitudinal reinforcing structure (3) reaching a preset thickness and a preset longitudinal depth is formed.

7. The construction method for preventing surging based on a temporary back cover structure according to claim 1, wherein the method for providing a water-proof reinforcing structure (4) further comprises:

Deep hole grouting is performed downwards in an inclined manner, which is 1.5m away from the inner wall of the vertical shaft, by the bottom sealing grouting steel pipe (40), wherein the inclined angle is 3-5 degrees, so that a part of bottom sealing structure which can be connected with the longitudinal reinforcing structure (3) is formed on the bottom sealing side surface of the vertical shaft, and the longitudinal reinforcing structure (3) is connected with the water-proof reinforcing structure (4) to form a complete closed reinforcing body.

8. The construction method for preventing surging based on the temporary back cover structure according to claim 1, wherein,

At least one primary lining structure (5) is arranged on the inner wall of the vertical shaft in the process of downwards excavating along the excavation surface of the vertical shaft;

after the vertical shaft is dug to a preset depth, a permanent bottom sealing structure (6) is arranged on the bottom plate of the vertical shaft.