CN117927275A - Waterproof construction method for underground excavation channel of subway - Google Patents

Abstract

The invention provides a subway underground excavation channel waterproof construction method which comprises the steps of waterproof layer construction, waterproof board grouting, secondary lining construction and secondary lining back grouting which are sequentially carried out; performing waterproof layer construction after the primary support of the underground excavation channel reaches the design strength, wherein the waterproof layer construction comprises the steps of construction preparation, geotechnical cloth buffer layer setting, waterproof board laying and waterproof layer protection; paving a geotextile buffer layer and a waterproof layer after construction preparation is completed; after the waterproof layer of the bottom plate is manufactured, a fine stone concrete waterproof layer is poured in time; the construction preparation steps comprise: removing the vertical septum support at the lower part of the grid steel frame, cutting off the vertical septum support from the root part of the vertical septum, and plastering cement mortar at the cutting-off part into a round curved surface; brushing a rubberized asphalt non-cured waterproof material at the position of the grid steel frame which is not dismantled for transition; the subway underground excavation channel waterproof construction method has the advantages of reliable scheme, simple and convenient construction, durable and applicable waterproof structure, and achieves the purposes of economy, rationality, safety and applicability and waterproof assurance.

Description

Waterproof construction method for underground excavation channel of subway

Technical Field

The invention belongs to the technical field of underground excavation channel waterproofing, and particularly relates to a subway underground excavation channel waterproofing construction method.

Background

Compared with the open cut method, the construction of the subway tunnel by adopting the shallow buried and underground excavation method has the advantages of low removal cost, small traffic influence and the like. The stratum of the underground excavation passage of the H-shaped access port of a certain station of the No.8 line is mainly positioned on clay soil and a clay soil layer with clay soil layers below a water level line, the dewatering difficulty is high, and risks such as a plastic flowing state and water leakage of soil bodies easily occur in the excavation process. The construction of underground passage adopts the CRD method of reserving core soil generally, in time sets up the grid steelframe and strut after the excavation, when waterproof construction, need demolish first vertical septum in order to lay the waterproof layer, and the septum after demolishing remains sharp corner easily, exists the hidden danger that cuts the waterproof board and causes groundwater seepage.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a waterproof construction method for a subway underground excavation channel.

In order to achieve the above object, the present invention provides the following technical solutions:

The subway underground excavation channel waterproof construction method comprises the following steps of waterproof layer construction, waterproof board grouting, secondary lining construction and secondary lining back grouting which are sequentially carried out;

Performing waterproof layer construction after the primary support of the underground excavation channel reaches the design strength, wherein the waterproof layer construction comprises the steps of construction preparation, geotechnical cloth buffer layer setting, waterproof board laying and waterproof layer protection; paving a geotextile buffer layer and a waterproof layer after construction preparation is completed; after the waterproof layer of the bottom plate is manufactured, a fine stone concrete waterproof layer is poured in time;

the construction preparation steps comprise: removing the vertical septum support at the lower part of the grid steel frame, cutting off the vertical septum support from the root part of the vertical septum, and plastering cement mortar at the cutting-off part into a round curved surface; and coating a rubberized asphalt non-cured waterproof material at the position of the undetached grille steel frame for transition.

Further, the grid steel frame is used for excavating a subway undercut channel by a CRD method, 4 guide holes are formed in the excavation process, the grid steel frame is formed by assembling 12 grids from a No. 1 grid to a No. 12 grid, the shape is regular, the whole grid steel frame is in a shape below an upper arc, the arch of the grid steel frame is round and smooth, the straight wall frames are straight and smooth, the straight wall frames are in smooth transition connection with the arch, the bottom frame is straight and is connected with straight wall frames on two sides in a right angle manner, the middle partition wall is in a cross shape which is horizontal and vertical, and the vertical middle partition is positioned at the center line of the guide hole; the vertical septum includes a number 3 grid in the upper portion and a number 6 grid in the lower portion.

Further, when the vertical middle partition support is removed, the No. 6 grille is removed firstly, only the No. 6 grille within the range of 300-500 mm above the bottom plate is removed, the grille is directly cut off by oxy-acetylene flame, and the grille in the thickness range of the bottom plate and other positions is reserved firstly; the cut part is smeared into a round curved surface by cement mortar so as to prevent the waterproof layer from being punctured, and the rubberized asphalt non-cured waterproof material is smeared at the part of the grid steel frame which is not dismantled for transition; then laying a geotextile buffer layer and a waterproof layer, constructing a fine stone concrete waterproof protective layer, and finishing the construction of the two substrate boards as soon as possible; then, according to the monitoring data condition, remaining the residual middle partition wall and temporary support, and applying a side wall waterproof layer and a second lining side wall; then, according to the monitoring data condition, remaining the remaining middle partition wall and temporary support, and applying a remaining waterproof layer and a secondary lining structure; and then, according to the monitoring data, when the strength of the secondary lining concrete reaches 100%, removing the middle partition plate and the middle partition wall, binding secondary lining steel bars of the arch wall, and pouring the secondary lining concrete in time to form a closed ring.

Further, the grid separation section No. 6 is removed, and the removal length of each section is not more than 4m.

Further, after the base layer is treated and accepted, cleaning floating ash, and then brushing a rubberized asphalt non-cured waterproof material at a grid steel frame for transition, wherein the dosage is 3kg/m ²; paving the rubberized asphalt non-cured waterproof material to 200mm on two sides of the undecut vertical septum, and connecting with the geotextile buffer layer; the rubberized asphalt non-cured waterproof material upwards covers a vertical middle partition with the height of 50mm, and two waterproof glue layers with the thickness of 20mm and 10mm are arranged at the positions of the upper edge of the rubberized asphalt non-cured waterproof material upwards at intervals of 100mm and 200 mm; the waterproof layer is paved on the rubberized asphalt non-solidified waterproof materials positioned on two sides and reaches the position of the vertical middle partition, and the edge of the waterproof layer is closed by a fixing piece.

Further, the weight of geotextile used for the geotextile buffer layer is not less than 400g/m ², the overlap joint of the geotextile is not less than 5cm, the geotextile buffer layer is paved from the arch part to side walls at two sides, the fixed point spacing is 0.6m, and the height of the side walls is 0.9m; the fixed points are arranged in a quincuncial shape; the waterproof board adopts an ECB plastic waterproof board with the thickness of 2.0 mm; the joint of the waterproof board is cleaned, the corner formed by the adjacent surfaces is made into an arc, and the radius of the arc is larger than 150mm; when the waterproof coiled material is paved, the waterproof coiled material is paved and pasted from the vault to two sides in turn along the annular direction, the lap joint length is not less than 100mm, the lap joint areas of two adjacent coiled materials are staggered, and the staggered position is not less than 600mm from the corner of the structure.

Further, the fine stone concrete waterproof protective layer is a C20 fine stone concrete waterproof protective layer with the thickness of 70 mm.

Further, the grouting of the waterproof board is constructed by adopting a waterproof board grouting system; the waterproof board grouting system comprises a grouting base and a grouting guide pipe, and the grouting base and the waterproof board are welded in a hot-melting way; the grouting guide pipe adopts a plastic threaded pipe and has enough compressive strength to ensure that the part embedded in the concrete is not flattened; the longitudinal spacing of the rings arranged in the grouting system is preferably 3-4 m; the grouting system is arranged as close to the deformation joint, the construction joint and the position of the wall penetrating pipe, which is easy to permeate water, the spacing between the special positions is preferably 50cm, and the circumferential spacing between the grouting systems at the two sides of the deformation joint is preferably properly encrypted to 2m; the grouting liquid adopts cement slurry with the water cement ratio of about 1 (2-3), and 8% -10% of expanding agent is added at the same time; the grouting pressure is controlled between 0.1MPa and 0.3MPa.

Further, the secondary lining is made of C35 waterproof reinforced concrete, the impervious grade is P8, and the thickness is 500 or 600mm; the construction of the second lining concrete of the underground excavation channel of the subway is carried out in 4 sections, a bottom plate is cast in each construction section, then a side wall and a vault are cast, and after the bottom plate is cast to reach the design strength, the formwork support of the side wall and the vault can be erected, and the construction of concrete casting can be carried out; the waterproof concrete is poured in sections and jumping sections, so that the primary pouring amount of the concrete is reduced, and the temperature stress of the concrete and the shrinkage of the concrete are controlled; before concrete is poured on the construction joint, roughening the joint surface, removing floating particles, washing with water, keeping moist, and paving cement mortar with the mortar-sand ratio identical to that of the concrete, so that new and old concrete at the construction joint can be effectively combined; in order to ensure the fluidity of the concrete, the slump is 160+/-20 mm on the side wall, the arch part is 180+/-20 mm, the slump loss before entering the mould is less than 10mm per hour, and the total slump loss value is not more than 10%; the concrete is poured symmetrically from bottom to top in layers, the pouring height of each layer is not more than 40cm, and the free fall of the waterproof concrete pouring is preferably controlled within the range of 2 m; fully vibrating the concrete by using a vibrator, and vibrating by using an attached vibrator, wherein the vibrating time of each point is generally 20-30; immediately covering the side wall and the vault with geotextile for water curing after removing the mould, wherein the difference between the surface temperature of the concrete and the surrounding environment is not more than 20 ℃ during removing the mould so as to prevent cracks from generating on the surface of the concrete, and the waterproof concrete is cured for not less than 14 days.

Further, grouting, plugging and waterproofing are carried out after secondary lining construction is carried out; grouting behind the secondary lining can be performed when the structural strength of the secondary lining reaches more than 75%, embedding the A42 steel welded pipe in the vault during secondary lining molding, embedding the A42 steel welded pipe during secondary lining pouring, and encrypting the arch part to 2-3 m, wherein the longitudinal distance is 4-5 m, the circumferential distance is 3-4 m; the non-shrinkage cement slurry is adopted as the grouting material for the back of the secondary lining, and the grouting pressure is 0.1 Mpa-0.3 Mpa.

Furthermore, the subway underground excavation channel waterproof construction method further comprises construction joint waterproof treatment and deformation joint waterproof treatment.

The beneficial effects of the invention are as follows:

The underground passage waterproof structure mainly comprises the self-waterproof structure, the geotextile buffer layer and the waterproof board, and prevents the detached middle partition from puncturing the waterproof board and timely protecting the paved bottom waterproof board through reasonable measures, so that the waterproof layer is prevented from being damaged by subsequent construction actions; meanwhile, grouting of the waterproof board and grouting of the secondary lining back ensure compactness and good impermeability of the integral waterproof layer and the lining structure;

The subway underground excavation channel waterproof construction method has the advantages of reliable scheme, simple and convenient construction and durable waterproof structure; the method achieves the compactness, impermeability, crack resistance, corrosion resistance and durability specified by the specification, and achieves the aims of advanced technology, economy, rationality, safety, applicability and water resistance assurance.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. Wherein:

Fig. 1 is a schematic layout diagram of a dewatering well according to an embodiment of the present invention.

Fig. 2 is a standard section waterproof construction diagram of an embodiment of the present invention.

Fig. 3 is a schematic structural view of a grid steel frame according to an embodiment of the invention.

Fig. 4 is a schematic diagram showing the sequence of removing the grille and the waterproof layer Shi Gongbu according to the embodiment of the present invention.

Fig. 5 is a schematic top view of a transition structure of a waterproof layer at a grid steel frame part according to an embodiment of the present invention.

Fig. 6 is a schematic front view of a waterproof layer transition structure at a grid steel frame part according to an embodiment of the present invention.

Fig. 7 is a schematic view of a deformation joint structure of a side wall and a top plate according to an embodiment of the present invention.

Fig. 8 is a schematic view of a deformation joint structure of a base plate according to an embodiment of the present invention.

Fig. 9 is a schematic view of a waterproof construction of a circumferential construction joint according to an embodiment of the present invention.

Fig. 10 is a schematic view of a waterproof construction of a longitudinal construction joint and a special portion according to an embodiment of the present invention.

Fig. 11 is a schematic longitudinal section view of grouting of a waterproof board according to an embodiment of the present invention.

Fig. 12 is a flow chart of a secondary lining construction process according to an embodiment of the present invention.

FIG. 13 is a standard cross-section template bracket view of a secondary lining according to an embodiment of the present invention.

Fig. 14 is a schematic diagram of a two-lining concrete construction section according to an embodiment of the present invention.

Detailed Description

The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which are derived by a person skilled in the art based on the embodiments of the invention, fall within the scope of protection of the invention.

In the description of the present invention, the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. refer to the orientation or positional relationship based on that shown in the drawings, merely for convenience of description of the present invention and do not require that the present invention must be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. The terms "coupled" and "connected" as used herein are to be construed broadly and may be, for example, fixedly coupled or detachably coupled; either directly or indirectly through intermediate components, the specific meaning of the terms being understood by those of ordinary skill in the art as the case may be.

The invention will be described in detail below with reference to the drawings in connection with embodiments. It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.

The H-shaped passageway is formed by grouting reinforcement of a full section and supporting of a greenhouse, and the earthwork excavation adopts a CRD method of reserving core soil; before the earthwork of the underground excavation channel is excavated, soil body support and reinforcement are needed to be adopted, the stability of the opening of a hole and the soil body excavated by the channel is ensured, two dewatering wells are respectively arranged on the north and south sides of the municipal tunnel, the bottom of the well extends into the bottom 8m of the channel, and the well depth is 26m;

Specifically, the well depth of two dewatering wells is 35.0m, and the dewatering wells are steel pipe wells; the diameter of the steel pipe is 273mm, the bridge type filter pipe (the interval between filter holes is 25mm transversely and 75mm longitudinally), 2 layers of 80-100 mesh nylon net are wrapped on the outer side of the filter pipe, and fine gravel materials are filled on the periphery of the well pipe; as shown in fig. 6, the south dewatering wells J1 and J2 are positioned at the north 2.5m of the outer wall surface of the station structure and at the east-west 1m of the outer wall surface of the channel structure; north dewatering wells J3 and J4 are positioned on the north wall facing south 2.0m of the enlarged section of the undercut channel and on the outer wall facing east and west 1m of the channel structure; pumping water from a dewatering well by using a 2kw submersible pump, wherein the depth of the lower pump is about 3.0m away from the bottom of the well; the submersible pump is suitable for the minimum well diameter of 200mm, the flow rate of 25m ³/h, the lift of 50m and the power of 2kw; by arranging the dewatering well, the influence of underground water on the construction of the underground tunnel is reduced;

when the dewatering well is constructed, the bottom opening of the mouth protecting pipe is inserted into an undisturbed soil layer, viscous soil is applied to seal the outside of the pipe, so that slurry returning outside the pipe is prevented during construction, and the upper part of the mouth protecting pipe is 0.10-0.30 m higher than the ground; adopting a crawler-type reverse circulation drilling machine with the diameter of 500mm to form holes, wherein the mud weight is 1.08-1.10; before the bottom of the pipe is lowered, ensuring that the thickness of the sediment at the bottom of the pipe is not more than 100mm, and lowering the filter pipe; after the construction of the dewatering well is completed, the well pipe of the dewatering well is 20-30 cm higher than the road of the construction site, and the well cover is added for protection, so that sundries are prevented from falling into the well.

The primary lining of the H-shaped access and exit undercut channel adopts C25P6 sprayed concrete, the secondary lining adopts C35P8 molded concrete, and the lining structure is self-waterproof; the primary lining sprayed concrete is C25P6 early strength concrete, the thickness is 300mm, and the full section is supported; the secondary lining is made of C35 waterproof reinforced concrete, has an anti-seepage grade P8 and is 500 or 600mm thick;

The underground structure of the underground passage has a waterproof grade of two stages, the top part of the underground structure is not allowed to drip, the other underground structure is not allowed to leak water, and a small amount of wet stains can be formed on the surface of the structure; the underground passageway is waterproof, mainly comprising a self-waterproof structure, a geotextile buffer layer and an ECB waterproof board with the thickness of 2.0mm, and meanwhile, the waterproof treatment of special parts such as joints, construction joints, settlement joints and the like is finished; the related waterproof system comprises structural waterproof and auxiliary waterproof, wherein the structural waterproof comprises a waterproof layer, a lining structure self-waterproof layer, a seam waterproof layer and auxiliary drainage measures; auxiliary waterproof mainly refers to secondary lining back grouting; the structural waterproof system is shown in Table 1:

table 1 structural waterproof systems table

The self-waterproof concrete structure mainly comprises waterproof concrete which is soaked in the concrete structure to a certain depth by virtue of the characteristics of the self-waterproof concrete so as not to penetrate; by adding the high-efficiency water reducer, the shrinkage of the concrete is reduced, the anti-seepage and anti-cracking performances are enhanced, the durability of the concrete is improved, and a series of measures are taken to ensure the construction quality of the concrete;

in this example, the primary lining waterproof shotcrete C25P6 is prepared from cement in a mixing ratio (1 m ³): water: sand: broken stone: accelerator = 1:0.51:1.95:1.95:0.05, and the primary lining waterproof sprayed concrete is self-waterproof; the underground excavation channel is also subjected to back backfill grouting, and the back backfill grouting has very obvious effect on controlling stratum settlement, seepage prevention and water blocking; the back filling grouting water prevention of the back of the primary support adopts cement slurry, and the water cement ratio of the cement slurry is determined by field test; and (3) pre-burying an A42 multiplied by 3.25mm steel welded pipe (length of 1000 mm) during primary support construction, and grouting at a position 3-5 m away from an excavation working face. The grouting holes are arranged along the top of the channel and the side walls, the circumferential spacing arching line is 2m above, the side walls are 3m, the longitudinal spacing is 3m, and the grouting holes are arranged in plum blossom shape; the grouting holes in the key areas are properly encrypted, the circumferential spacing arching line is 1m above, the side wall is 2m, the longitudinal spacing is 2.0m, and the grouting holes are arranged in plum blossom shape; and back grouting is timely carried out every 2m of longitudinal excavation, and the final grouting pressure is controlled at 0.5MPa. The slurry is cement slurry, and the proportion is determined according to field tests; grouting is performed in a sequence from top to bottom.

After the primary lining of the channel is penetrated, primary lining acceptance is required, penetration deviation, channel deviation and repairing work are measured, and large pits and peaks on the surface of the lining of the channel are repaired; before waterproofing, the primary lining partition wall is removed in a staged manner; after the middle partition wall is formed into a ring on the full section, the middle partition wall can be removed after the displacement of each part is stable enough to bear the whole pressure of the soil body; (1) After the deformation stability of the soil body is judged according to the monitoring data, the temporary vertical support is removed firstly; the temporary support is not excessively long each time, and the partition is applied, and the application length of each section is not more than 4m; after the temporary support is removed, paving a bottom plate waterproof layer, constructing a fine stone concrete waterproof layer and finishing the bottom plate construction as soon as possible; if the monitoring data are abnormal, timely supplementing the detached partition wall; (2) After the lower waterproof construction is finished, judging that the deformation of the soil body is stable according to the monitoring data, removing the horizontal temporary support and the upper vertical temporary support, and longitudinally removing the temporary support section to a length not more than 4m, and performing the partition construction; paving the residual waterproof layer in time after dismantling; if the monitoring data are abnormal, timely supplementing the upper vertical temporary support, and connecting the upper vertical temporary support with the lower vertical temporary support by bolts; and binding second lining steel bars of the arch wall after the temporary support is removed, and pouring second lining concrete in time to form a closed ring.

As shown in fig. 3, the excavation process is divided into 4 pilot holes, the grid steel frames are formed by assembling 12 grids from a grid 1 to a grid 12, the shape is regular, the whole grid steel frames are in a shape below an upper arc, the arch frames of the grid steel frames (including a top arch and a wall arch) are round and smooth, the straight wall frames are straight and smooth, the straight wall frames are in transition connection with the arch frames, the whole bottom frames are straight and are connected with the straight wall frames at right angles at two sides, the middle partition wall is a cross shape which is horizontal and vertical, and the vertical middle partition is positioned at the center line of the pilot hole; the grid 1, the grid 8, the grid 2 and the grid 9 form a top arch, the grid 3 and the grid 6 form a vertical middle partition, the grid 4 and the grid 10 form a horizontal middle partition, the lower part of the grid 2 and the grid 5 form a straight wall frame on one side, the lower part of the grid 9 and the grid 11 form a straight wall frame on the other side, and the grid 7 and the grid 12 are used as underframes; the grid corresponds to the pilot hole, and the pilot hole No. 1 is supported by the grid No. 1, the grid No. 2, the grid No. 3 and the grid No. 4; the guide hole No. 2 is supported by a grid No. 4, a grid No. 6, a grid No. 5 and a grid No. 7; the guide hole No. 3 is supported by a grid No. 3, a grid No. 8, a grid No. 9 and a grid No. 10; the guide hole No. 4 is supported by a grid No. 6, a grid No. 10, a grid No. 11 and a grid No. 12; the grid steelframe of this embodiment is regular, and the chassis is straight, and easy cutting when dispelling vertical septum and supporting, and flat chassis makes lower part pilot tunnel shape be the rectangle, and the concrete surface of spraying after the excavation is flat to easy expansion is difficult for hollowing, fold when geotechnique's cloth and waterproof board are laid.

When the secondary lining structure is applied, as shown in fig. 2 to 4, firstly, removing the No. 6 grille, removing only the No. 6 grille within the range of 300-500mm above the bottom plate, directly cutting by oxy-acetylene flame, and retaining the grille within the thickness range of the bottom plate (the grille between the No. 7 grille and the grille between the No. 12 grille) and other positions; removing the No. 6 grid partition, wherein the removing length of each section is not more than 4m, the removed part is smeared into a round curved surface by cement mortar so as to prevent the waterproof layer from being punctured, and the positions of the non-removed grid steel frames are coated with rubberized asphalt non-cured waterproof materials for transition; and then laying a geotextile buffer layer and a waterproof layer, and constructing a fine stone concrete waterproof protective layer to finish the construction of the two substrate boards as soon as possible. And secondly, according to the condition of the monitoring data, reserving the rest middle partition walls and temporary supports, and applying a side wall waterproof layer and a two-lining side wall, wherein the height of the side wall is close to that of the horizontal middle partition wall. And thirdly, according to the condition of the monitoring data, remaining the remaining middle partition wall and temporary support, and applying a remaining waterproof layer and a secondary lining structure. And fourthly, according to the monitoring data, when the strength of the secondary lining concrete reaches 100%, removing the middle partition plate and the middle partition wall, binding secondary lining steel bars of the arch wall, pouring the secondary lining concrete in time to form a closed ring, and performing waterproof construction.

Specifically, the waterproof layer construction method comprises the following steps:

① Preparation for construction

A. Before the waterproof board is paved, the strength requirement of the primary support concrete reaches the design strength; the flatness is required to meet the design specification, otherwise, cement mortar with the ratio of 1:1.25 is adopted for leveling until the flatness meets the requirement; the base surface must not have sharp protrusions such as steel bars, iron wires, steel pipes and the like, otherwise, the base surface must be cut off from the root, and a circular curved surface is smeared with cement mortar at the cut-off position so as to prevent the waterproof layer from being punctured; when the ruler is used for checking, the gap between the ruler and the base surface is not more than 5mm, and the gap is not more than one place in each meter length, and the gap is only allowed to be changed gently;

b. and (3) basal surface treatment: when the waterproof layer is constructed, the basal plane must not have bright water, if bright water adopts grouting to block water or guide and discharge, and the basal plane is kept dry; removing impurities such as floating soil, mud, oil stains and the like on the structure, and ensuring that the base surface is flat and has no leakage before the waterproof layer is paved;

② Geotextile buffer layer arrangement

The buffer layer is paved from the arch part to the side walls at two sides; smoothly fixing geotextile on the primary support sprayed concrete surface, wherein the distance between fixed points is 0.6m, and the height of a side wall is 0.9m; the fixing points are arranged in a quincuncial shape, and the fixing points are added at the larger convex-concave parts of the base surface so that the buffer layer is closely adhered to the base surface; the weight of the geotextile is not less than 400g/m ², the overlap joint of the geotextile is not less than 5cm, and the laid buffer layer is smooth, has no bulge and no wrinkles;

③ Waterproof board laying

A. The waterproof board adopts an ECB plastic waterproof board with the thickness of 2.0 mm; the joint of the waterproof board is cleaned, the corner formed by the adjacent surfaces is made into an arc, and the radius of the arc is larger than 150mm;

b. the one-time paving length of the waterproof board can be determined according to factors such as construction conditions, concrete circulation grouting length and the like, and before paving, the waterproof board is required to be paved in a trial mode and adjusted;

c. the connecting part of the waterproof board is protected before the next stage of construction, so that the waterproof board cannot be stained and damaged;

d. after the base layer is treated and accepted, cleaning floating ash, and then brushing a rubberized asphalt non-cured waterproof material at a grid steel frame for transition, wherein the dosage is 3kg/m ²; fig. 5 and 6 are schematic views of transition structures of waterproof layers at the grid steel frame parts, wherein the rubberized asphalt non-cured waterproof materials are paved to 200mm at two sides of an undecut vertical middle partition and are connected with a geotextile buffer layer; the rubberized asphalt non-cured waterproof material upwards covers a vertical middle partition with the height of 50mm, and two waterproof glue layers with the thickness of 20mm and 10mm are arranged at the positions of the upper edge of the rubberized asphalt non-cured waterproof material upwards at intervals of 100mm and 200 mm; the waterproof layer is paved on the rubberized asphalt non-curing waterproof materials positioned on two sides and reaches the position of the vertical middle partition, and the edge of the waterproof layer is closed by a fixing piece;

f. When the waterproof coiled materials are paved, the waterproof coiled materials are paved and pasted from the vault to two sides in turn along the circumferential direction, the lap joint length is not less than 100mm, the lap joint areas of two adjacent coiled materials are staggered, and the staggered position is not less than 600mm from the corner of the structure; when the buffer layer is paved, the buffer layer is paved along the structural ring direction, and the buffer layer cannot be pulled too tightly, so that certain looseness is reserved; the waterproof coiled material is installed in a fixed mode of steel nails, and the nail parts are repaired and covered by the waterproof coiled material; the coiled material is laid smoothly, stretched, wrinkled and raised, and no empty drum, close adhesion and firm adhesion are required during later laying, so that water leakage cannot occur;

④ Protection of waterproof layer

The laid waterproof layer is specially protected, and the damage to the waterproof plate caused by transportation and binding of the reinforcing steel bars is paid attention to; and repairing the waterproof layer in time when the waterproof layer is found to be damaged. Timely pouring protective layer concrete after the waterproof layer of the bottom plate is manufactured; the channel is used for timely pouring the C20 fine stone concrete waterproof layer with the thickness of 70mm on the bottom plate waterproof layer, fine stone is used as coarse aggregate for the fine stone concrete waterproof layer, the fluidity and plasticity of concrete are improved, and the compactness of the concrete is improved under the same condition, so that the construction efficiency is improved, the cost is reduced, the economical efficiency of the concrete is improved, the leveling is easy, the high-efficiency construction of the next procedure is facilitated, and the construction quality is improved. Arranging geotextile protective layers on the side walls and the vault, and adopting geotextile with the density of 400 g/square meter as a waterproof structure buffer layer; when the steel bar is bound at the position without the protective layer, the waterproof layer is not damaged, the shoes with nails are strictly forbidden to walk on the waterproof layer, and the layers are timely repaired when the layers are damaged; the geotextile and waterproof board construction is shown in the standard section waterproof construction diagram of figure 2.

Specifically, as the two ends of the underground excavation channel are connected with the open excavation section or the open excavation station, a deformation joint is required to be arranged at the joint, the waterproof structure of the deformation joint comprises a back-attached water stop belt arranged at the outer side of the deformation joint, a steel edge rubber water stop belt with a grouting pipe arranged at the middle part of the deformation joint, and stainless steel water receiving tanks arranged at the arch part of the deformation joint and at the inner side of the side wall, and the inner side of the deformation joint is embedded with sealing glue; the steel edge rubber water stop with the grouting pipe forms a closed waterproof line, and the stainless steel water receiving tank can lead a small amount of water seepage into the underground excavation channel drainage ditch in an organized manner; FIG. 7 shows a side wall and top panel deformation joint structure, and FIG. 8 shows a bottom panel deformation joint structure;

specifically, the circumferential construction joint spacing of the underground excavation channel is 9-15 m; the joint of the construction joint and the inverted arch as well as the side wall is staggered, the construction joint is left on the wall body 300mm higher than the intersection point of the side wall and the inverted arch, and when a reserved hole is formed in the wall body, the distance between the construction joint and the edge of the hole is not less than 300mm; the waterproof structure of the circumferential construction joint comprises a geotextile buffer layer arranged on the inner side of a plastic waterproof board, a waterproof board reinforcing layer arranged on the inner side of the geotextile buffer layer, a steel edge rubber water stop strip arranged in the middle of the deformation joint and a water stop glue arranged between the construction joint and the steel edge rubber water stop strip, wherein the waterproof board reinforcing layer adopts a single-layer plastic waterproof cloth with the width of 500 mm; FIG. 9 is a view showing a waterproof construction of a circumferential construction joint according to an embodiment of the present invention;

The longitudinal construction joint is additionally provided with two water stopping lines except the auxiliary waterproof layer: arranging a galvanized steel sheet water stop belt with the thickness of 5mm or embedding a grouting pipe capable of repeatedly grouting in the middle of the longitudinal construction joint; fig. 10 is a schematic view of a waterproof construction of a longitudinal construction joint and a special portion according to an embodiment of the present invention.

Specifically, due to the specificity of the construction process of the secondary lining concrete of the undermining engineering, a very small gap is easy to generate between a concrete structure and a waterproof layer; in order to ensure the compactness of the whole structure, a waterproof board grouting system is adopted for grouting and waterproof treatment; as shown in fig. 11, the waterproof board grouting system comprises a grouting base and a grouting guide pipe, wherein the grouting base and the waterproof board are welded in a hot-melting way; the grouting guide pipe adopts a plastic threaded pipe and has enough compressive strength to ensure that the part embedded in the concrete is not flattened; the longitudinal spacing of the rings arranged in the grouting system is preferably 3-4 m; the grouting system is arranged as close to the positions which are easy to permeate water, such as the deformation joint, the construction joint, the wall penetrating pipe and the like, the spacing between the special positions is preferably 50cm, and the circumferential spacing between the grouting systems at the two sides of the deformation joint is preferably properly encrypted to 2m; the grouting liquid adopts cement slurry with the water cement ratio of about 1 (2-3), and 8% -10% of expanding agent is added at the same time; grouting pressure is determined according to the water leakage condition, the structure thickness, the burial depth and other factors, and can be controlled to be generally 0.1 MPa-0.3 MPa or determined according to field tests; the back backfill grouting system arranged on the arch of the second lining cannot replace the waterproof board grouting system; after the construction of the secondary lining structure is completed, if water leakage occurs, grouting is carried out between the waterproof board and the secondary lining by using a grouting system.

Further, the strength grade of the secondary lining concrete of the underground excavation channel adopts C35 concrete when the underground water is non-corrosive, and the impermeability grade is P8; the standard section channel is lined by an integral full-hall fastener scaffold, a shaping I-steel main rib and a combined steel mould, and pumping concrete is poured;

The waterproof concrete construction is carried out after the primary support of the excavation is basically stable; when the secondary lining structure is constructed, the inverted arch is in advance, and the lining template is adopted for integral pouring of the secondary lining of the arch wall; the arch wall is longitudinally segmented according to the length of 6 meters; inverted arch concrete pouring and arch bottom concrete filling advanced arch wall concrete for 30cm to form line production; when pumping concrete, pumping concrete of the concrete tank truck into the concrete pump in the hole through the ground conveying pump, and pouring the concrete into the working surface through the conveying pump; a feed port can be arranged if necessary; according to the overall construction arrangement, the underground excavation channel lining is operated in a single process; FIG. 12 is a secondary lining construction flow chart;

As shown in fig. 13 and 14, after the secondary lining steel bars of the underground excavation channel are bound, inverted arch and side wall templates are installed, and side wall and roof concrete is poured; the H-shaped passageway for the entrance and the exit comprises a standard section and an enlarged section, wherein the construction of the second lining concrete is carried out in 4 sections, the standard section part is divided into 3 sections (the lengths of the single sections are 9.23m, 9.23m and 9.24 m), and the enlarged section part is 1 section (the length is 15.1 m); C35P8 mold concrete is adopted as the second lining; pouring a bottom plate at each construction section, then pouring side walls and vaults, and after the bottom plate is poured to reach the design strength, building a template bracket of the side walls and the vaults and performing concrete pouring construction; the waterproof concrete is poured in sections and jumping sections, so that the primary pouring amount of the concrete is reduced, and the temperature stress of the concrete and the shrinkage of the concrete are controlled; before concrete is poured on the construction joint, roughening the joint surface, removing floating particles, washing with water, keeping moist, and paving cement mortar with the mortar-sand ratio identical to that of the concrete, so that new and old concrete at the construction joint can be effectively combined; in order to ensure the fluidity of the concrete, the slump is 160+/-20 mm on the side wall, the arch part is 180+/-20 mm, the slump loss before entering the mould is less than 10mm per hour, and the total slump loss value is not more than 10%; the concrete is poured symmetrically from bottom to top in layers, the pouring height of each layer is not more than 40cm, the free fall of the waterproof concrete pouring is preferably controlled within a range of 2m, and when the height exceeds 2m, a string barrel and a chute are used; the distance between the two feeding holes is not more than 2m; the concrete is fully vibrated by a vibrator, and is vibrated by an attached vibrator, wherein the vibrating time of each point is generally 20-30 s, and the concrete is free from leakage vibration, lack of vibration and excessive vibration, so that the uniformity and compactness of the concrete are ensured, and the crack resistance of the concrete is improved; various steel bars or binding iron wires are arranged in the waterproof concrete structure, the waterproof concrete structure is not contacted with the template, and water stopping measures are required to be arranged when bolts for fixing the template must pass through the concrete structure; the pouring sequence of each layer is started from the constructed end of the concrete, so that the joint quality of the concrete construction joint is ensured, and the exhaust is convenient; strictly controlling the molding temperature of the concrete, utilizing construction at night as much as possible during construction in summer and high-temperature seasons, taking measures to reduce the molding temperature of the concrete, wherein the highest molding temperature is not more than 35 ℃; concrete pouring is continuously carried out, horizontal and inclined joints are not generated, if the concrete pouring is interrupted due to reasons, the hardened front layer concrete surface soft layer and cement mortar film must be chiseled off before the pouring construction is continued, and the surface is chiseled, and the high-pressure water is used for washing cleanly; the phenomena of incompact vault concrete, insufficient pouring and the like are often generated due to vault concrete pouring; when the concrete is poured, the concrete is uniformly distributed and poured from the contact surface of the new concrete and the old concrete, and finally the extrusion pumping pouring is carried out at the middle position of the unit body; when the concrete is squeezed out of the baffle head plate, the pressure is stabilized for a few minutes to see whether the concrete is full or not, if the stabilized pressure can not be refilled, the vault is indicated to be full; immediately covering the side wall and the vault with geotextile for water curing after removing the mould, wherein the difference between the surface temperature of the concrete and the surrounding environment is not more than 20 ℃ when removing the mould so as to prevent cracks from occurring on the surface of the concrete, curing the waterproof concrete for not less than 14 days, and timely watering and curing the waterproof concrete during curing to keep the concrete moist; polishing the joints of the two lining template brackets after the two lining template brackets are removed, and plastering the joints by adopting equal-label glue-doped mortar if necessary to ensure the roundness of the vault outline; the secondary lining construction ensures the quality and lining thickness of secondary lining concrete and the lining appearance.

Further, grouting, plugging and waterproofing are carried out after secondary lining construction is carried out; grouting behind the secondary lining can be performed when the structural strength of the secondary lining reaches more than 75%, embedding the A42 steel welded pipe in the vault during secondary lining molding, embedding the A42 steel welded pipe during secondary lining pouring, and encrypting the arch part to 2-3 m, wherein the longitudinal distance is 4-5 m, the circumferential distance is 3-4 m; the non-shrinkage cement slurry is adopted as the grouting material for the back of the secondary lining, and the grouting pressure is 0.1 Mpa-0.3 Mpa.

The water prevention of the underground excavation channel is realized by taking the principle of 'taking prevention as the main part, combining rigid and flexible, setting multiple fortifications, taking place according to local conditions and comprehensively treating', and paying importance to each link in the construction process, so that the water prevention construction quality is ensured, the design principle is a reinforced concrete structure self-waterproof system, and effective technical measures are taken to ensure that the waterproof concrete achieves the compactness, impermeability, crack resistance, corrosion resistance and durability specified in the specification; reinforcing deformation joints, construction joints, wall penetrating pipes, embedded parts, reserved holes, various joints, various structural section interfaces and other detail waterproof measures: ① During the excavation construction, observation records are made on the water seepage condition, the water seepage position, the water quantity and the like of the channel. If the water seepage is large, a proper method is selected to seal the water; ② When the primary support is excavated, if larger water flows out in a stranded way, a water pipe can be buried to lead out water, and then grouting and water shutoff are carried out after the primary support is sprayed with concrete to reach the strength; ③ The construction process of the sprayed concrete is improved, the compactness and the surface flatness of the sprayed concrete are improved, and the possibility of water leakage is reduced; attach importance to the primary support base surface treatment work and provide reliable guarantee for the construction quality of the flexible waterproof layer; ④ During the construction of the primary support, back grouting is required to be carried out on the primary support, and back backfilling is carried out on the back of the primary support; filling gaps between the primary support and the soil body, and plugging the water permeable channel to basically achieve a primary water stopping effect; ⑤ After the primary support is finished and before water is applied, performing secondary system grouting and water shutoff treatment on the leakage part of the primary support, so that the primary support is basically free of leakage; the underground structure of the underground passage has a waterproof grade of two stages.

The waterproof system constructed by the construction method comprises structural waterproof and auxiliary waterproof, wherein the structural waterproof comprises primary building structure self-waterproof, waterproof layer, secondary lining structure self-waterproof, joint waterproof and auxiliary drainage measures; the auxiliary waterproofing comprises a primary back backfill grouting system, a waterproof board grouting system, a secondary lining back grouting system and a fine stone concrete waterproof layer on a bottom plate waterproof layer; through reasonable measures, the detached middle partition wall is prevented from puncturing the waterproof board, the paved bottom waterproof board is timely protected, and the waterproof layer is prevented from being damaged by subsequent construction actions; simultaneously, grouting the waterproof board and grouting the back of the secondary lining ensures the compactness and impermeability of the integral waterproof layer and the lining structure; the subway underground excavation channel waterproof construction method has the advantages of reliable scheme, simple and convenient construction, durable and applicable waterproof structure, and achieves the purposes of economy, rationality, safety and applicability and waterproof assurance.

It is to be understood that the above description is intended to be illustrative, and that the embodiments of the present application are not limited thereto. The foregoing description of the preferred embodiments of the application is not intended to limit the application to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the application as defined by the appended claims.

Claims (10)

1. A subway underground excavation passage waterproof construction method is characterized by comprising the following steps of: the method comprises the following steps of waterproof layer construction, waterproof board grouting, secondary lining construction and secondary lining back grouting which are sequentially carried out;

Performing waterproof layer construction after the primary support of the underground excavation channel reaches the design strength, wherein the waterproof layer construction comprises the steps of construction preparation, geotechnical cloth buffer layer setting, waterproof board laying and waterproof layer protection; paving a geotextile buffer layer and a waterproof layer after construction preparation is completed; after the waterproof layer of the bottom plate is manufactured, a fine stone concrete waterproof layer is poured in time;

the construction preparation steps comprise: removing the vertical septum support at the lower part of the grid steel frame, cutting off the vertical septum support from the root part of the vertical septum, and plastering cement mortar at the cutting-off part into a round curved surface; and coating a rubberized asphalt non-cured waterproof material at the position of the undetached grille steel frame for transition.

2. The subway undercut channel waterproof construction method according to claim 1, characterized in that: the grid steel frame is used for excavating a subway undercut channel by a CRD method, the excavation process is divided into 4 pilot holes, the grid steel frame is formed by assembling 12 grids from a No.1 grid to a No. 12 grid, the shape is regular, the whole grid steel frame is in a shape below an upper arc, the arch frame of the grid steel frame is round and smooth, the straight wall frames are straight and smooth, the straight wall frames are in smooth transition connection with the arch frames, the whole bottom frame is straight and is connected with the straight wall frames at right angles at two sides, the middle partition wall is a cross shape which is horizontal and vertical, and the vertical middle partition is positioned at the center line of the pilot hole; the vertical septum includes a number 3 grid in the upper portion and a number 6 grid in the lower portion.

3. The subway undercut channel waterproof construction method according to claim 2, characterized in that: when the vertical middle partition support is removed, removing the No. 6 grille, only removing the No. 6 grille within the range of 300-500 mm above the bottom plate, directly cutting off the grille by oxy-acetylene flame, and retaining the grille in the thickness range of the bottom plate and other positions; the cut part is smeared into a round curved surface by cement mortar so as to prevent the waterproof layer from being punctured, and the rubberized asphalt non-cured waterproof material is smeared at the part of the grid steel frame which is not dismantled for transition; then laying a geotextile buffer layer and a waterproof layer, constructing a fine stone concrete waterproof protective layer, and finishing the construction of the two substrate boards as soon as possible; then, according to the monitoring data condition, remaining the residual middle partition wall and temporary support, and applying a side wall waterproof layer and a second lining side wall; then, according to the monitoring data condition, remaining the remaining middle partition wall and temporary support, and applying a remaining waterproof layer and a secondary lining structure; and then, according to the monitoring data, when the strength of the secondary lining concrete reaches 100%, removing the middle partition plate and the middle partition wall, binding secondary lining steel bars of the arch wall, and pouring the secondary lining concrete in time to form a closed ring.

4. The subway undercut passageway waterproof construction method according to claim 3, characterized in that: and 6, removing the grid separation sections, wherein the removing length of each section is not more than 4m.

5. The subway undercut channel waterproof construction method according to claim 1, characterized in that: after the base layer is treated and accepted, cleaning floating ash, and then brushing a rubberized asphalt non-cured waterproof material at a grid steel frame for transition, wherein the dosage is 3kg/m ²; paving the rubberized asphalt non-cured waterproof material to 200mm on two sides of the undecut vertical septum, and connecting with the geotextile buffer layer; the rubberized asphalt non-cured waterproof material upwards covers a vertical middle partition with the height of 50mm, and two waterproof glue layers with the thickness of 20mm and 10mm are arranged at the positions of the upper edge of the rubberized asphalt non-cured waterproof material upwards at intervals of 100mm and 200 mm; the waterproof layer is paved on the rubberized asphalt non-solidified waterproof materials positioned on two sides and reaches the position of the vertical middle partition, and the edge of the waterproof layer is closed by a fixing piece.

6. The subway undercut channel waterproof construction method according to claim 1, characterized in that: the weight of geotextile used for the geotextile buffer layer is not less than 400g/m ² cm, the overlap joint of the geotextile is not less than 5cm, the geotextile buffer layer is paved from the arch part to the side walls at two sides, the fixed point spacing is 0.6m, and the height of the side walls is 0.9m; the fixed points are arranged in a quincuncial shape; the waterproof board adopts an ECB plastic waterproof board with the thickness of 2.0 mm; the joint of the waterproof board is cleaned, the corner formed by the adjacent surfaces is made into an arc, and the radius of the arc is larger than 150mm; when the waterproof coiled material is paved, the waterproof coiled material is paved and pasted from the vault to two sides in turn along the annular direction, the lap joint length is not less than 100mm, the lap joint areas of two adjacent coiled materials are staggered, and the staggered position is not less than 600mm from the corner of the structure.

7. The subway undercut channel waterproof construction method according to claim 1, characterized in that: the fine stone concrete waterproof protective layer is a C20 fine stone concrete waterproof protective layer with the thickness of 70 mm.

8. The subway undercut channel waterproof construction method according to claim 1, characterized in that: grouting the waterproof board by adopting a waterproof board grouting system; the waterproof board grouting system comprises a grouting base and a grouting guide pipe, and the grouting base and the waterproof board are welded in a hot-melting way; the grouting guide pipe adopts a plastic threaded pipe and has enough compressive strength to ensure that the part embedded in the concrete is not flattened; the longitudinal spacing of the rings arranged in the grouting system is preferably 3-4 m; the grouting system is arranged as close to the deformation joint, the construction joint and the position of the wall penetrating pipe, which is easy to permeate water, the spacing between the special positions is preferably 50cm, and the circumferential spacing between the grouting systems at the two sides of the deformation joint is preferably properly encrypted to 2m; the grouting liquid adopts cement slurry with the water cement ratio of about 1 (2-3), and 8% -10% of expanding agent is added at the same time; the grouting pressure is controlled between 0.1MPa and 0.3MPa.

9. The subway undercut channel waterproof construction method according to claim 1, characterized in that: the secondary lining is made of C35 waterproof reinforced concrete, the impervious grade is P8, and the thickness is 500mm or 600mm; the construction of the second lining concrete of the underground excavation channel of the subway is carried out in 4 sections, a bottom plate is cast in each construction section, then a side wall and a vault are cast, and after the bottom plate is cast to reach the design strength, the formwork support of the side wall and the vault can be erected, and the construction of concrete casting can be carried out; the waterproof concrete is poured in sections and jumping sections, so that the primary pouring amount of the concrete is reduced, and the temperature stress of the concrete and the shrinkage of the concrete are controlled; before concrete is poured on the construction joint, roughening the joint surface, removing floating particles, washing with water, keeping moist, and paving cement mortar with the mortar-sand ratio identical to that of the concrete, so that new and old concrete at the construction joint can be effectively combined; in order to ensure the fluidity of the concrete, the slump is 160+/-20 mm on the side wall, the arch part is 180+/-20 mm, the slump loss before entering the mould is less than 10mm per hour, and the total slump loss value is not more than 10%; the concrete is poured symmetrically from bottom to top in layers, the pouring height of each layer is not more than 40cm, and the free fall of the waterproof concrete pouring is preferably controlled within the range of 2 m; fully vibrating the concrete by using a vibrator, and vibrating by using an attached vibrator, wherein the vibrating time of each point is generally 20-30 s; immediately covering the side wall and the vault with geotextile for water curing after removing the mould, wherein the difference between the surface temperature of the concrete and the surrounding environment is not more than 20 ℃ during removing the mould so as to prevent cracks from generating on the surface of the concrete, and the waterproof concrete is cured for not less than 14 days.

10. The subway undercut channel waterproof construction method according to claim 1, characterized in that: grouting, plugging and waterproofing are carried out after secondary lining construction; grouting behind the secondary lining can be performed when the structural strength of the secondary lining reaches more than 75%, embedding the A42 steel welded pipe in the vault during secondary lining molding, embedding the A42 steel welded pipe during secondary lining pouring, and encrypting the arch part to 2-3 m, wherein the longitudinal distance is 4-5 m, the circumferential distance is 3-4 m; the non-shrinkage cement slurry is adopted as the grouting material for the back of the secondary lining, and the grouting pressure is 0.1 Mpa-0.3 Mpa.