CN211973508U - Deep foundation pit supporting anti-seepage system for coastal karst stratum - Google Patents
Deep foundation pit supporting anti-seepage system for coastal karst stratum Download PDFInfo
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- CN211973508U CN211973508U CN201921925883.1U CN201921925883U CN211973508U CN 211973508 U CN211973508 U CN 211973508U CN 201921925883 U CN201921925883 U CN 201921925883U CN 211973508 U CN211973508 U CN 211973508U
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Abstract
The utility model discloses a deep foundation pit supporting seepage-proofing system of a coastal karst stratum, which comprises a supporting structure, a karst cave treatment structure and a horizontal waterproof curtain, wherein the supporting structure comprises a drilling secant pile, a waist beam, a crown beam and an inner support, and the drilling secant pile is arranged around a foundation pit and forms a closed seepage-proofing body; the horizontal waterproof curtain is arranged right below the bottom of the foundation pit. The utility model discloses a karst cave treatment measure can prevent the risk that the karst cave developed rapidly under the groundwater action, has improved the local ability of collapsing of the anti karst of ground. The utility model discloses a combined supporting system who supports in drilling secant pile + not only strut effectually, supporting construction deformability is little, need not be assisted in addition with waterproof measures such as stagnant water curtain moreover. The utility model discloses a level is to the stagnant water curtain adopt the mode of slip casting to carry out stagnant water treatment to the foundation ditch bottom region, can effectively cut off the effective passageway of the karst crack water of pit bottom, thoroughly solves the problem that the water gushed at the bottom of the pit.
Description
Technical Field
The utility model relates to a foundation ditch engineering technical field, especially a coastal karst stratum's deep basal pit struts prevention of seepage system.
Background
The coastal karst stratum belongs to complex hydrogeological conditions and has higher requirements on the supporting and seepage-proofing capacity of foundation pit engineering. Karst is the general term for various surface and underground corrosion phenomena caused by chemical erosion, disintegration, mechanical destruction, transportation and deposition of soluble rock formations (carbonates, sulfates, halides, etc.) by surface water and groundwater. With the prosperity and development of the economy of China, various building projects are pulled out like bamboo shoots in spring after rain. Among various civil engineering, geotechnical engineering plays an important role. In the case of geotechnical engineering of the coastal karst stratum, because the coastal karst stratum contains abundant fracture water, in the excavation process of a deep foundation pit (a foundation pit with the excavation depth of more than 5 m), the side wall and the bottom of the foundation pit are faced with serious karst fracture water problems, and corresponding water stopping measures are necessary. If a conventional foundation pit pile anchor supporting structure is adopted, the water seepage situation of the side wall cannot be completely avoided even if a vertical water-stopping curtain is additionally arranged, and the water leakage situation at the bottom of the pit cannot be completely treated. Similar difficulties are encountered with the remaining forms of supporting structures. Similar to the supporting form of the underground continuous wall, the cost is higher. At present, few construction examples of deep foundation pits in karst development areas at home and abroad exist, mature technical experiences are not available, and an effective method for treating the deep foundation pits in the coastal karst stratum is absolutely required to be explored.
SUMMERY OF THE UTILITY MODEL
The utility model aims to overcome the foundation ditch engineering infiltration problem in coastal karst stratum, provide the deep basal pit of coastal karst stratum who can effectively solve the serious infiltration problem in the coastal karst stratum deep basal pit excavation process and strut prevention of seepage system.
Realize the utility model discloses technical scheme that the purpose was taken as follows:
a deep foundation pit supporting anti-seepage system of a coastal karst stratum comprises a supporting structure, a karst cave treatment structure and a horizontal waterproof curtain, wherein the supporting structure comprises drilling secant piles and a crown beam, the drilling secant piles are arranged around a foundation pit and form a closed anti-seepage body, and the crown beam is arranged at the top of the drilling secant piles; the karst cave treatment structure is positioned at the periphery of the foundation pit and below the bottom of the foundation pit; the horizontal waterproof curtain is arranged right below the bottom of the foundation pit;
the drilling secant pile is composed of a reinforced concrete pouring pile and a plain concrete pouring pile, and the reinforced concrete pouring pile is embedded between the plain concrete pouring piles.
Furthermore, the inner side of the drilling secant pile is provided with a waist beam, an inner support is arranged between the waist beams on the left side and the right side, and the inner support is a reinforced concrete beam or a steel beam.
Furthermore, the karst cave treatment structure is positioned within 5m of the periphery of the foundation pit and within 10m of the bottom of the foundation pit.
Furthermore, the karst cave processing structure comprises a half-filled karst cave processing body, a non-filled karst cave processing body and a flowing plastic soft plastic sticky soil full-filled karst cave processing body.
Further, the drilling secant pile is fixedly connected with the crown beam in a pouring mode.
Further, the drilling diameter of the drilling occlusion pile is 800-1200 mm.
Furthermore, the waist rail is fixedly connected with the drilled occlusive pile in a bar planting mode, and the waist rail is fixedly connected with the inner support in a welding mode.
Further, the distance between the inner supports is less than 4 m.
Further, the semi-filling karst cave treatment body is gravel, broken stone, flow plastic soft plastic sticky soil and cement water glass concrete; the filling-free karst cave treatment body is gravel, broken stone and cement water glass concrete; the fluid-plastic soft-plastic cohesive soil full-filling karst cave treatment body is a fluid-plastic soft-plastic cohesive soil and cement water glass concrete body.
Further, the thickness of the horizontal waterproof curtain is larger than 3 m.
Compared with the prior art, the beneficial effects of the utility model are as follows:
1. the utility model discloses a risk that solution cavity treatment measure preventable solution cavity developed rapidly under groundwater action has avoided supporting construction to produce when the construction and collapses and the foundation ditch takes place the risk of surging suddenly under the effect of high water head karst confined water, has improved the anti karst local ability of collapsing of ground.
2. The utility model discloses a combined supporting system who supports in drilling secant pile + not only strut effectually, supporting construction deformability is little, need not assist waterproof measures such as stagnant water curtain in addition moreover, the infiltration condition appears very few in the foundation ditch lateral wall. Compared with other enclosure structure forms (such as underground continuous walls and the like) meeting the same engineering requirements, the comprehensive economic benefit has obvious advantages:
the reinforcement rate is lower. The drilled secant pile is usually arranged in a mode that reinforced concrete piles and plain concrete piles are arranged at intervals, so that the reinforcement ratio of the supporting structure is greatly reduced. ② the impermeability is stronger. The drilling secant pile is continuously constructed, construction joints do not exist among the piles, and the construction joints at the framing joints of the underground continuous wall are often weak links for seepage prevention; construction is flexible, and the transformation line can be turned as required during construction of the drilling occlusive pile, so that the construction method is more suitable for constructing some geometrical figures with variable planes or foundation pits in various arcs. And fourthly, the full casing drilling machine is adopted, and the advanced steel casing protecting wall is always arranged in the construction process, so that the mud protecting wall is not needed, and the cost for manufacturing and using the mud and treating the waste mud is saved. The reaming (filling) coefficient is smaller, because the steel sleeve retaining wall is always arranged in the construction process, the collapse of the hole wall is completely avoided, thereby reducing the reaming (filling) coefficient and reducing the concrete pouring amount.
3. The utility model discloses a level is to the stagnant water curtain adopt the mode of slip casting to carry out stagnant water treatment to the foundation ditch bottom region, can effectively cut off the effective passageway of the karst crack water of pit bottom, thoroughly solves the problem that the water gushed at the bottom of the pit.
4. The utility model discloses a water glass be a grouting material commonly used, water glass self has stronger adhesion, and acid-fast corrosion is strong, and can get into in the capillary, and blocking material's pore prevents its osmotic action behind the sclerosis. The water glass slurry has the characteristics of short gelling time, good injectability and controllability and the like. The cement water glass slurry is used as a grouting material, so that the setting time of the cement slurry is shortened, the cement slurry is prevented from being eroded by underground water and not easy to solidify, and the water interception and seepage prevention performance of the horizontal waterproof curtain can be obviously improved.
5. The horizontal waterproof curtain and the drilling secant pile jointly form a waterproof and anti-seepage system, so that a good closed body is formed on the side wall of the foundation pit and the bottom of the foundation pit, the drilling secant pile around the foundation pit and the horizontal waterproof curtain below the substrate can better play a role in supporting, and the influence of soil around the foundation pit on the stability of the foundation pit is small.
Drawings
Fig. 1 is a schematic sectional view of a foundation pit supporting anti-seepage system during construction of a drilling secant pile.
Fig. 2 is a schematic sectional view of a foundation pit supporting seepage-proofing system when a waterproof curtain is horizontally constructed.
Fig. 3 is a schematic sectional view of a foundation pit supporting anti-seepage system during foundation pit excavation.
Fig. 4 is a top view of fig. 3.
Fig. 5 is a schematic cross-sectional view of a drilled bite pile.
In the figure: 1. the method comprises the following steps of 1, ground 2, a drilled secant pile 3, the bottom of a foundation pit 4, a horizontal waterproof curtain 5, an inner support 6, a waist beam 7, a crown beam 8, a karst cave treatment structure 9, a grouting hole 21, a plain concrete pouring pile 22 and a reinforced concrete pouring pile.
Detailed Description
The invention is explained in more detail below with reference to the figures and examples, without limiting the scope of the invention to the details.
As shown in fig. 1-5, the deep foundation pit supporting seepage-proofing system of the coastal karst stratum comprises a supporting structure, a karst cave treatment structure 8 and a horizontal waterproof curtain 4, wherein the supporting structure comprises drilling secant piles 2, waist beams 6, crown beams 7 and inner supports 5, the drilling secant piles 2 are arranged around a foundation pit and form a sealed seepage-proofing body, the top parts of the drilling secant piles 2 are provided with the waist beams 7, the inner sides of the drilling secant piles 2 are provided with the waist beams 6, and the inner supports 5 are arranged between the waist beams 6 on the left side and the right side; the karst cave treatment structure 8 is positioned at the periphery of the foundation pit and below the bottom 3 of the foundation pit; the horizontal waterproof curtain 4 is arranged right below the bottom 3 of the foundation pit;
the bored secant pile 2 is composed of a reinforced concrete cast pile 22 and a plain concrete cast pile 21, and the reinforced concrete cast pile 22 is embedded between the plain concrete cast piles 21.
Further, the inner support 5 is a reinforced concrete beam or a steel beam.
Further, the karst cave treatment structure 8 is located within 5m of the periphery of the foundation pit and within 10m of the bottom 3 of the foundation pit.
Further, the karst cave treatment structure 8 comprises a half-filled karst cave treatment body, a non-filled karst cave treatment body and a fluid-plastic soft-plastic cohesive soil full-filled karst cave treatment body.
Further, the drilling secant pile 2 and the crown beam 7 are fixedly connected in a pouring mode.
Further, the drilling diameter of the drilling engagement pile 2 is 800-.
Further, the wale 6 is fixedly connected with the drilled secant pile 2 in a bar planting mode, and the wale 6 is fixedly connected with the inner support 5 in a welding mode.
Further, the distance between the inner supports 5 is less than 4 m.
Further, the semi-filling karst cave treatment body is gravel, broken stone, flow plastic soft plastic sticky soil and cement water glass concrete; the filling-free karst cave treatment body is gravel, broken stone and cement water glass concrete; the fluid-plastic soft-plastic cohesive soil full-filling karst cave treatment body is a fluid-plastic soft-plastic cohesive soil and cement water glass concrete body.
Further, the thickness of the horizontal waterproof curtain 4 is more than 3 m.
The utility model discloses a construction method, including following step:
A. measuring and placing a ground red line for construction, finishing the setting of a construction enclosure, and carrying out foundation pit construction after leveling the ground;
B. in order to ensure the safety of the foundation pit, carrying out karst cave treatment within the range of 10m below the bottom 3 of the foundation pit and 5m around the foundation pit; the processing method comprises the following steps:
b1, for the semi-filled karst cave, filling gravel and broken stone, and then grouting cement-water glass slurry through the grouting holes 9 to form a semi-filled karst cave treatment body;
b2, for the unfilled karst cave, filling gravel and broken stone, and then grouting the cement-water glass slurry through the grouting holes 9 to form an unfilled karst cave treatment body;
b3, directly carrying out grouting on cement water glass slurry through the grouting holes 9 to form a full-filling karst cave treatment body for the full-filling karst cave;
C. a firm construction guide groove is made in advance according to the position of the drilled secant pile 2 of a design drawing, a measuring instrument is used for positioning the pile point of the drilled secant pile 2, corresponding drilling equipment is selected, a first batch of drilled holes are constructed, plain concrete is poured into the first batch of drilled holes, and a plain concrete pouring pile 21 is formed;
D. after the first batch of drilling plain concrete is poured for 60 +/-2 hours, namely before the concrete is initially set, performing second batch of drilling construction between two holes of the first batch of drilling holes, after the drilling is finished, putting a reinforcement cage and pouring concrete to form reinforced concrete pouring piles 22, and embedding the reinforced concrete pouring piles 22 between the plain concrete pouring piles 21 to form drilling secant piles 2;
E. after the construction of the drilled secant pile 2 is finished and the periphery of the foundation pit is sealed by the drilled secant pile 2, the construction of a pile top crown beam 7 is started;
F. preparing cement slurry according to the design proportion, preparing the cement slurry, and then doping the cement slurry into the water glass; the cement paste has the water cement mass ratio of 0.75-1, and the water glass doping amount is 2-4% of the cement paste mass;
G. grouting the position right below the bottom 3 of the foundation pit through the grouting holes 9 to form a horizontal waterproof curtain 4, and ensuring that the jacking force of the bearing water at the lower part of the horizontal waterproof curtain 4 is not greater than the soil pressure above the horizontal waterproof curtain 4;
H. excavating foundation pits in layers from the ground 1, and erecting a waist beam 6 and an inner support 5 in time;
I. after the foundation pit is excavated to the designed elevation, the bottom 3 of the foundation pit is leveled manually, then a broken stone mattress layer and a C15 concrete mattress layer are constructed according to the design requirement, and the mattress layer is leveled according to the design requirement.
The present invention is not limited to the embodiment, and any equivalent concept or change within the technical scope of the present invention is all listed as the protection scope of the present invention.
Claims (10)
1. A deep foundation pit supporting anti-seepage system for a coastal karst stratum is characterized in that: the construction method comprises a supporting structure, a karst cave treatment structure (8) and a horizontal waterproof curtain (4), wherein the supporting structure comprises drilling secant piles (2) and a crown beam (7), the drilling secant piles (2) are arranged around a foundation pit and form a closed anti-seepage body, and the crown beam (7) is arranged at the top of the drilling secant piles (2); the karst cave treatment structure (8) is positioned at the periphery of the foundation pit and below the bottom (3) of the foundation pit; the horizontal waterproof curtain (4) is arranged right below the bottom (3) of the foundation pit;
the drilling secant pile (2) is composed of reinforced concrete cast piles (22) and plain concrete cast piles (21), and the reinforced concrete cast piles (22) are embedded between the plain concrete cast piles (21).
2. The system of claim 1, wherein the system is used for supporting and preventing seepage of deep foundation pits of the coastal karst stratum and comprises: the inner side of the drilling secant pile (2) is provided with a waist beam (6), an inner support (5) is arranged between the waist beams on the left side and the right side, and the inner support (5) is a reinforced concrete beam or a steel beam.
3. The system of claim 1, wherein the system is used for supporting and preventing seepage of deep foundation pits of the coastal karst stratum and comprises: the karst cave treatment structure (8) is positioned within the range of 5m of the periphery of the foundation pit and within the range of 10m of the bottom (3) of the foundation pit.
4. The system of claim 1, wherein the system is used for supporting and preventing seepage of deep foundation pits of the coastal karst stratum and comprises: the karst cave processing structure (8) comprises a half-filled karst cave processing body, a non-filled karst cave processing body and a flow-plastic soft-plastic sticky soil full-filled karst cave processing body.
5. The system of claim 1, wherein the system is used for supporting and preventing seepage of deep foundation pits of the coastal karst stratum and comprises: the drilling secant pile (2) is fixedly connected with the crown beam (7) in a pouring mode.
6. The system of claim 1, wherein the system is used for supporting and preventing seepage of deep foundation pits of the coastal karst stratum and comprises: the drilling diameter of the drilling occlusive pile (2) is 800-1200 mm.
7. The system of claim 2, wherein the system is used for supporting and preventing seepage of deep foundation pits of the coastal karst stratum, and comprises: the wale (6) is fixedly connected with the drilling secant pile (2) in a bar planting mode, and the wale (6) is fixedly connected with the inner support (5) in a welding mode.
8. The system of claim 2, wherein the system is used for supporting and preventing seepage of deep foundation pits of the coastal karst stratum, and comprises: the distance between the inner supports (5) is less than 4 m.
9. The system of claim 4, wherein the system is used for preventing seepage of deep foundation pits of the coastal karst stratum and comprises: the semi-filling karst cave treatment body is gravel, broken stone, flow plastic soft plastic sticky soil and cement water glass concrete; the filling-free karst cave treatment body is gravel, broken stone and cement water glass concrete; the fluid-plastic soft-plastic cohesive soil full-filling karst cave treatment body is a fluid-plastic soft-plastic cohesive soil and cement water glass concrete body.
10. The system of claim 1, wherein the system is used for supporting and preventing seepage of deep foundation pits of the coastal karst stratum and comprises: the thickness of the horizontal waterproof curtain (4) is more than 3 m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921925883.1U CN211973508U (en) | 2019-11-11 | 2019-11-11 | Deep foundation pit supporting anti-seepage system for coastal karst stratum |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921925883.1U CN211973508U (en) | 2019-11-11 | 2019-11-11 | Deep foundation pit supporting anti-seepage system for coastal karst stratum |
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| CN211973508U true CN211973508U (en) | 2020-11-20 |
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| CN201921925883.1U Active CN211973508U (en) | 2019-11-11 | 2019-11-11 | Deep foundation pit supporting anti-seepage system for coastal karst stratum |
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