CN113356221B - Polluted foundation pit supporting and rapid excavation construction method - Google Patents
Polluted foundation pit supporting and rapid excavation construction method Download PDFInfo
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- CN113356221B CN113356221B CN202110741591.8A CN202110741591A CN113356221B CN 113356221 B CN113356221 B CN 113356221B CN 202110741591 A CN202110741591 A CN 202110741591A CN 113356221 B CN113356221 B CN 113356221B
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/02—Foundation pits
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D1/00—Investigation of foundation soil in situ
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D15/00—Handling building or like materials for hydraulic engineering or foundations
- E02D15/02—Handling of bulk concrete specially for foundation or hydraulic engineering purposes
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/02—Foundation pits
- E02D17/04—Bordering surfacing or stiffening the sides of foundation pits
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/02—Sheet piles or sheet pile bulkheads
- E02D5/03—Prefabricated parts, e.g. composite sheet piles
- E02D5/04—Prefabricated parts, e.g. composite sheet piles made of steel
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/74—Means for anchoring structural elements or bulkheads
- E02D5/76—Anchorings for bulkheads or sections thereof in as much as specially adapted therefor
Abstract
The invention discloses a polluted foundation pit supporting and rapid excavation construction method, which comprises the following steps: before the polluted foundation pit is excavated, cleaning the periphery of the polluted foundation pit, leveling the site, cleaning slurry on the construction site, and then measuring and lofting the construction site; dividing the polluted foundation pit into a first work area, a second work area and a third work area; step two: arranging a water retaining wall at the periphery of a polluted foundation pit, and casting and forming by adopting concrete, wherein the water retaining wall is arranged along the periphery of the polluted foundation pit in a full length manner; step three: and respectively detecting the soil of the pit walls of the first working area, the second working area and the third working area in the process of excavation of the foundation pit, wherein the first working area is a heavy metal pollution foundation pit, and the second working area is an organic pollution foundation pit. The method solves the problems that the existing method for excavating the polluted foundation pit is low in safety and excavation speed, the pit wall of the foundation pit cannot be detected, a reasonable construction method is formulated according to the pollution condition of soil, the construction period is increased intangibly, and the construction efficiency is reduced.
Description
Technical Field
The invention relates to the technical field of civil engineering, in particular to a polluted foundation pit support and rapid excavation construction method.
Background
The existing repair method of the heavy metal polluted site mainly comprises burying, phytoremediation, bioremediation, soil leaching, solidification stabilization, various integrated repair technologies and the like, wherein the burying method is characterized in that the polluted soil is excavated and then placed at a designated site and covered by uncontaminated soil;
the polluted site repairing technology can be divided into an in-situ repairing technology and an ex-situ repairing technology according to repairing sites, and the in-situ repairing technology does not move polluted soil and directly repairs the polluted site, so that the method has the characteristics of good effect, small secondary pollution and the like; the ex-situ remediation technology is to excavate out the polluted soil, treat the polluted soil after in-situ ex-situ or transportation, has a short remediation period and a more controllable remediation effect than in-situ remediation, but is easy to cause secondary pollution in the process of excavation, and has higher construction cost of excavation and transportation for the large-area polluted soil;
in the Chinese invention patent application CN108746171A, the problems of complex working procedures and high cost of the existing excavation process are mainly solved, but foundation pit support is not added in the actual excavation process, so that certain potential safety hazards exist in the excavation process;
in the Chinese patent application CN101773928A, the application discloses a treatment method for in-situ solidification and isolation of a heavy metal industrial pollution site, but the method only solidifies pollutants in soil in the pollution site, and the state or the form of the pollutants are not changed, so that a large pollution risk still exists;
therefore, we propose a pollution foundation pit support and rapid excavation construction method.
Disclosure of Invention
The invention provides a polluted foundation pit support and rapid excavation construction method for solving the technical problems.
In order to achieve the above purpose, the present invention provides the following technical solutions:
a method for supporting and quickly excavating a polluted foundation pit comprises the following steps
Step one: before the polluted foundation pit is excavated, cleaning the periphery of the polluted foundation pit, leveling a site, cleaning slurry on a construction site, and then measuring and lofting the construction site; dividing the polluted foundation pit into a first work area, a second work area and a third work area;
step two: a water retaining wall formed by concrete pouring is arranged on the periphery of the polluted foundation pit, and the water retaining wall is arranged along the periphery of the polluted foundation pit in a full length mode;
step three: the polluted foundation pit is used for respectively detecting the soil on the pit walls of the foundation pit in the first working area, the second working area and the third working area in the excavation process; wherein the first working area is a heavy metal pollution foundation pit, the second working area is an organic pollution foundation pit, and the third working area is a phosphorus pollution foundation pit;
step four: adopting a slope-releasing excavation mode in the construction process of the polluted foundation pit, wherein slope protection measures are net hanging and anchor spraying; arranging a plurality of steel pipe columns on the polluted foundation pit, and connecting steel sheet pile assemblies among the plurality of steel pipe columns; a transverse plate is arranged at the top end of the steel pipe column, and a detection assembly and an alarm assembly are respectively arranged on the lower end face of the transverse plate;
step five: reserving protective films on the slope surface when excavating the first working area, the second working area and the third working area, manually carrying out slope surface trimming by matching with machinery, and carrying out slope surface supporting in time after finishing slope surface trimming; until the foundation pit is excavated to the bottom of the foundation pit;
step six: leveling and cleaning broken stone on the substrate of the polluted foundation pit, and checking and accepting the plane position of the substrate, the elevation of the substrate and the geology of the substrate of the polluted foundation pit after leveling and cleaning broken stone.
According to the method, pit wall soil can be detected in the excavating process, different construction methods are adopted according to different detection results, so that foundation pits can be excavated effectively and rapidly, a good construction effect is achieved, and meanwhile, the method has high safety performance.
Preferably, the steel sheet pile assembly comprises a first steel sheet pile welded on the steel pipe column and a second steel sheet pile connected to the first steel sheet pile in a threaded manner, and a plurality of buffer springs and air filling columns are arranged between the first steel sheet pile and the second steel sheet pile; the detection assembly comprises a plurality of infrared sensors arranged on the lower end face of the cross rod; the alarm assembly comprises a buzzer and a singlechip which are arranged on the lower end surface of the cross rod; the singlechip, the buzzer and the infrared sensor are electrically connected; the top of diaphragm is equipped with the photovoltaic board.
The water retaining wall is mainly used for ensuring that field rainwater cannot flow into a foundation pit to cause loss during rainstorm in rainy season, a water collecting well is arranged at intervals of 50m along drainage ditches around the field and the foundation pit and is used as an auxiliary drainage facility during rainstorm, a dewatering well is arranged in the foundation pit, a positive circulation drilling machine is adopted in the pore forming process, 2m deep gravel or medium coarse sand is firstly put into the bottom of the pore after the pore forming is finished, then a water filtering pipe is hung, the water filtering pipe adopts a phi 400/300mm cement gravel water filtering pipe, a 60-mesh nylon net is wrapped outside the water filtering pipe, the water filtering pipe is hung in the well by an automobile, the well pipe is placed vertically and is positioned in the middle of a well hole, the top of the water filtering pipe is about 50cm higher than the ground, reinforcing measures are taken, the well pipe is lowered to the design depth, and fine gravel filtering materials with the particle size of 3-7 mm are filled between the well pipe and the wall in time after the water filtering well pipe is put into the hole. The filter material must meet the grading requirement, the particles outside the upper and lower limits of the designed gravel specification are screened out, the qualification rate is greater than 90%, the impurity content is not greater than 3%, a spade is used for blanking to prevent the layering unevenness and the impact of the well pipe, the filter material filling is continuously completed at one time, 1m below the well mouth is filled from bottom, the upper part is backfilled and sealed by ramming the clay layering without sand stone, the last step is flushing, the main purpose of flushing is to clear the slurry and the slurry of the wall of the hole and the permeable layer, dredge the permeable layer, form a good back filtering layer around the well, the pressure is 0.8Mpa, and the exhaust gas is 9m 3 And (3) the air compressor and the submersible pump are combined to wash the well until clear water is pumped out. The difference of water inflow of the water pumping before and after the well flushing is less than 15 percent, and the sediment in the well does not rise after the well flushing.
Preferably, in the fourth step, the measuring and lofting instrument before construction adopts a total station, and an excavation boundary is drawn; in the excavation process, a large excavator and a small excavator are matched for excavation, and a closed dump truck is used for deslagging; and when the slope is excavated to 20cm, the slope is repaired by manual cooperation, and soil nailing construction is performed.
Preferably, the soil nails are cement mortar soil nails, and a construction mode of grouting firstly and then inserting the soil nails is adopted.
Wherein, the permanent support soil nails which are firstly grouted are inserted with soil nails immediately after grouting is fully performed in the drilling holes; the permanent support soil nail of back slip casting carries out the slip casting immediately after soil nail installation, firstly inserts the slip casting pipe to the hole bottom, then withdraws from 50 ~ 100mm, begins the slip casting, and the slip casting pipe is slowly at uniform velocity along with the injection of mortar and pulls out, inserts soil nail immediately after filling the thick liquid in the drilling, and soil nail hole slip casting must be closely knit, fills mortar in the hole after the soil nail installation, and the length in the body of rod patchhole is not less than 95% of design length, and after the soil nail installation is accomplished, before the mortar solidifies, must not strike, collide and draw the soil nail, keeps 48h at least soil nail not disturbed.
Preferably, in the fourth step, the polluted foundation pit is excavated by adopting 1:1 slope-releasing excavation, and each layer of excavation is carried out once net hanging and spraying protection until the pit bottom.
The foundation pit is excavated according to the designed slope ratio strictly in the process of excavating the foundation pit, overexcavation is strictly forbidden, the slope is repaired in time, the evenness of the slope surface is guaranteed, the excavation depth and length of each step are reduced at the position with poor slope surface stability, the spacing between dowel bars is 1m, and the quincuncial arrangement is realized; the point positions are released by the total station, marks are made on the point positions, slope dowel bars are C20 steel bars, the length of the slope dowel bars is 3m, the slope dowel bars are perpendicular to the slope surface after insertion, the thickness of a protection layer of a soil facing surface of a reinforcing steel bar net is controlled to be 5cm, a water drain pipe with the length of 0.5m is inserted into the back of a supporting surface layer, the water drain pipe is horizontally arranged in a quincuncial manner, the density of the arrangement is 2000 x 2000, a Luoyang shovel is adopted to dig a soil body during installation, and blockage of water drain holes is prevented.
Preferably, in the fourth step, the concrete is sprayed firstly to form a concrete surface layer, then the fine stone concrete is sprayed, and the distance between the spray head and the sprayed surface is 0.6-1.2 m.
Wherein inclined planes with 45-degree angles are formed among the middle sheets and among the layers, and concrete spraying equipment adopts an air compressorThe air volume of the air compressor is not less than 9m 3 And/min, the air pressure is 0.2-0.5 Mpa, the water pressure of a spray head is not less than 0.15MPa, the spraying distance is controlled to be 0.6-1.0 m, and the sprayed surface layer needs to be subjected to water spraying maintenance for one week.
Preferably, in the fifth step, the first work area and the second work area are firstly subjected to pollution boundary and excavation boundary measurement paying-off in the excavation process, and multi-layer excavation of polluted soil is performed, and in the excavation process, supporting is performed while excavation is performed; after the upper layer of polluted soil is excavated, paving HDPE film separation on the surface of the lower layer of polluted soil;
the three-work area is a heavy pollution area, the periphery of the heavy pollution area is sealed by Larson steel piles, excavation is not carried out, the tops of the Larson steel piles are exposed out of the ground for 50cm, a lock catch waist beam is arranged on the outer side of each Larson steel pile, then reinforcement is carried out, and point monitoring is carried out.
The method comprises the steps of firstly measuring and paying off a pollution boundary and an excavation boundary in an excavation process of a heavy metal polluted foundation pit, then excavating polluted soil, directly excavating a peripheral station of the foundation pit by adopting a long-arm excavator, loading a TAC320 excavator, paving an HDPE film on the surface of the next layer of polluted soil after the upper layer of polluted soil is excavated, and then excavating peripheral clean soil, wherein the second working area is an organic polluted foundation pit, the excavation mode is the same as that of the first working area, and the three working areas contain more phosphorus and are more serious in pollution, so that the periphery of the foundation pit is sealed by Lassen steel piles in the early stage of excavation, wherein the Lassen steel piles are constructed by adopting a crawler excavator, before piling, workers are required to check the pile body one by one, remove rust which is seriously deformed, the steel piles which are seriously deformed can not be used until the repair is qualified after the repair is finished, and the repair is still qualified, and the repair is required to be disabled; before piling, grease is smeared in a locking notch of the Larson steel pile, so that the pile bodies are convenient to drive and pull out, the inclination of each pile body is required to be measured and monitored to be not more than 2% in the inserting and driving process, when the inclination is overlarge, the Larson steel pile is required to be aligned by using a pull Ji Fangfa, if the Larson steel pile cannot be aligned, the Larson steel pile is required to be lifted and driven, after the Larson steel pile is completely driven, larson steel piles on two sides of an open channel are respectively connected into a whole by using H200 by 11 by 19mm I-steel, the Larson steel piles are required to be respectively connected into a whole at the position about 1.5m below the pile top, then the Larson steel piles on two sides are symmetrically supported by using a movable section at intervals of 5m, the Larson steel piles on two sides are required to be screwed up by using a movable section, so as to ensure the verticality of the Larson steel pile and the working face of a foundation pit excavation, the change condition of the Larson pile is required to be observed at any time in the foundation pit excavation process, and if obvious capsizing or uplift states are required to be immediately increased by workers at the symmetrical supporting positions.
Preferably, in the construction process of the Larson steel pile, according to the requirement of the width of the excavation section of the polluted foundation pit, the Larson steel pile driving position line is measured and marked.
Preferably, the Larson steel piles are driven by a crawler excavator, and the inclination of each Larson steel pile is not more than 2% in the Larson steel pile inserting and driving process; and after the Larson steel piles are applied, respectively connecting Larson steel piles on two sides of the open channel into a whole by using the I-shaped steel, and firmly welding the Larson steel piles by using an welding rod.
Preferably, in the third step, soil conditions of the pit walls of the first working area, the second working area and the third working area are detected by using a soil detection sensor.
Compared with the prior art, the invention has the following beneficial effects:
1. the method is suitable for treating the places with serious pollution, and has the advantages of high excavation speed and high safety performance; 2. the process equipment investment and the operation cost are low, and the position of a treatment site is not limited; 3. the invention adopts the sealing measures for construction, has simpler construction steps, is safe and reliable in construction process, can effectively avoid the diffusion of pollutants in complex underground environment in time, and is also beneficial to the further centralized treatment of the pollutants.
Drawings
FIG. 1 is a flow chart of a foundation pit construction process of the invention;
FIG. 2 is a flow chart of a soil nail construction process in the invention;
FIG. 3 is a flow chart of a Larson steel pile construction process in the invention;
FIG. 4 is a schematic front view of Larson steel plate according to the present invention;
FIG. 5 is a top view of the Larson plate and rail assembly of the present invention;
fig. 6 is a plan view of the larsen steel sheet according to the present invention.
Description of the drawings: 1. a steel pipe column; 2. a first steel sheet pile; 3. steel sheet piles II; 4. a buffer spring; 5. an inflatable column; 6. a cross plate; 7. an infrared sensor; 8. a photovoltaic panel; 9. and an alarm device.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
Referring to FIG. 1, a method for supporting and rapidly excavating a polluted foundation pit includes
Step one: before the polluted foundation pit is excavated, cleaning the periphery of the polluted foundation pit, leveling the site, cleaning slurry on the construction site, and then measuring and lofting the construction site; dividing a polluted foundation pit into a first work area, a second work area and a third work area;
step two: arranging a water retaining wall at the periphery of the polluted foundation pit, and casting and forming by adopting concrete, wherein the water retaining wall is arranged along the periphery of the polluted foundation pit in a full length manner; the water retaining wall formed by concrete pouring has the height of 30cm and the thickness of 10cm; 1 water collecting well of 1m by 1m is arranged around the polluted foundation pit along the drainage ditch at intervals of 50 cm; and a water intercepting ditch with the diameter of 0.3m by 0.3m is arranged at the position of the top of the polluted foundation pit, which is at least 3m away from the top line of the excavated slope of the polluted foundation pit.
Step three: the method comprises the steps of respectively detecting pit wall soil of a first work area, a second work area and a third work area in the process of excavating a polluted foundation pit, wherein the first work area is a heavy metal polluted foundation pit, the second work area is an organic polluted foundation pit, and the third work area is a phosphorus polluted foundation pit; if the soil pollution is detected to be serious, the excavation is continued, otherwise, the slope is put down;
step four: the method is characterized in that a slope-releasing excavation mode is adopted in the construction process of the polluted foundation pit, if the depth of the polluted foundation pit is 0-4m, slope is released according to a gradient coefficient of 1:1.2, and slope protection measures are anchor spraying by hanging; if the depth of the polluted foundation pit is below 6m, slope is laid according to a gradient coefficient of 1:1.5, a plurality of steel pipe columns are arranged on the polluted foundation pit, and steel sheet pile assemblies are connected between the plurality of steel pipe columns; a transverse plate is arranged at the top end of the steel pipe column, and a detection assembly and an alarm assembly are respectively arranged on the lower end face of the transverse plate;
step five: reserving protective films on the slope surface when excavating the first working area, the second working area and the third working area, manually finishing the slope surface by matching with machinery, and supporting the slope surface in time after finishing the slope surface; after the slope support reaches the strength required by standardization, the next layer of excavation is carried out until the excavation is carried out to the bottom of the foundation pit;
step six: leveling and cleaning broken stone on the substrate of the polluted foundation pit, and checking and accepting the plane position of the substrate, the elevation of the substrate and the geology of the substrate of the polluted foundation pit after leveling and cleaning broken stone.
The water retaining wall is mainly used for ensuring that field rainwater cannot flow into a foundation pit to cause loss during rainstorm in rainy season, a water collecting well is arranged at intervals of 50m along drainage ditches around the field and the foundation pit and is used as an auxiliary drainage facility during rainstorm, a dewatering well is arranged in the foundation pit, a positive circulation drilling machine is adopted in the pore forming process, 2m deep gravel or medium coarse sand is firstly put into the bottom of the pore after the pore forming is finished, then a water filtering pipe is hung, the water filtering pipe adopts a phi 400/300mm cement gravel water filtering pipe, a 60-mesh nylon net is wrapped outside the water filtering pipe, the water filtering pipe is hung in the well by an automobile, the well pipe is placed vertically and is positioned in the middle of a well hole, the top of the water filtering pipe is about 50cm higher than the ground, reinforcing measures are taken, the well pipe is lowered to the design depth, and fine gravel filtering materials with the particle size of 3-7 mm are filled between the well pipe and the wall in time after the water filtering well pipe is put into the hole. The filter material must meet the grading requirement, the particles outside the upper and lower limits of the designed gravel specification are screened out, the qualification rate is more than 90%, the impurity content is not more than 3%, a spade is used for blanking to prevent the layering non-uniformity and the impact on the well pipe, the filter material filling is continuously completed at one time, 1m from the bottom filling to the lower part of the well mouth, the upper part is provided with clay layering backfill without sand stone and ramming sealing mouthThe final step is well flushing, which mainly aims at removing the slurry and the slurry of the wall of the hole, dredging the permeable layer, forming a good reverse filtering layer around the well, adopting the pressure of 0.8Mpa and the exhaust gas of 9m 3 And (3) the air compressor and the submersible pump are combined to wash the well until clear water is pumped out. The difference of water inflow of the water pumping before and after the well flushing is less than 15 percent, and the sediment in the well does not rise after the well flushing.
Preferably, in the fourth step, the measuring and lofting instrument before construction adopts a total station, and an excavation boundary is drawn; in the excavation process, a large excavator and a small excavator are matched for excavation, and a closed dump truck is used for deslagging; and when the slope is excavated to 20cm, the slope is repaired by manual cooperation, and soil nailing construction is performed.
Example two
Referring to fig. 2, in the method for supporting and quickly excavating a polluted foundation pit, preferably, soil nails are cement mortar soil nails, and full-length grouting soil nails are mainly formed by adopting 16mm three-stage hot rolled steel bars and M30 cement mortar, and a construction mode of grouting firstly and then inserting the soil nails is adopted; the pumice on the side slope is pried off, the rock surface is cleaned up, and drilling positions are arranged; mortar soil nails with the soil nail length less than 6m are drilled by adopting a YT-28 hand drill, and the soil nails are firstly injected and then installed; drilling holes by adopting a YG80 guide rail type rock drill with the soil nails of which the lengths are more than 6m, and grouting after the soil nails are installed; after the drilling is finished, the hole is washed by high-pressure air and water in the hole is blown out.
Wherein, the permanent support soil nails which are firstly grouted are inserted with soil nails immediately after grouting is fully performed in the drilling holes; the permanent support soil nail of back slip casting carries out the slip casting immediately after soil nail installation, firstly inserts the slip casting pipe to the hole bottom, then withdraws from 50 ~ 100mm, begins the slip casting, and the slip casting pipe is slowly at uniform velocity along with the injection of mortar and pulls out, inserts soil nail immediately after filling the thick liquid in the drilling, and soil nail hole slip casting must be closely knit, fills mortar in the hole after the soil nail installation, and the length in the body of rod patchhole is not less than 95% of design length, and after the soil nail installation is accomplished, before the mortar solidifies, must not strike, collide and draw the soil nail, keeps 48h at least soil nail not disturbed.
Example III
Referring to fig. 3, in a fifth step, a first working area and a second working area are preferably selected, during the excavation, a pollution boundary and an excavation boundary are measured and paid off, during the multi-layer excavation of polluted soil, during the excavation, the supporting is performed while the excavation is performed, and the excavation mode adopts vertical layering, longitudinal segmentation and supporting along with the excavation; after the upper layer of polluted soil is excavated, paving HDPE film separation on the surface of the lower layer of polluted soil, cleaning soil around the excavation, and placing slopes and pit walls for soil detection and support;
the method comprises the steps of firstly sealing the periphery of a heavy pollution area by using Larson steel piles, temporarily excavating, exposing the tops of the Larson steel piles to the ground by 50cm, arranging a lock waist beam on the outer side of a Larson steel plate, then carrying out opposite side opposite pulling reinforcement, fully casting concrete with the thickness of 50cm on the inner surface of the square Larson steel pile, carrying out point monitoring, constructing foundation pit dewatering wells, carrying out foundation pit dewatering, paying off the excavated boundaries of the heavy pollution area after the dewatering wells are completed, and carrying out polluted soil excavation;
the method comprises the steps of firstly measuring and paying off a pollution boundary and an excavation boundary in an excavation process of a heavy metal polluted foundation pit, then excavating polluted soil, directly excavating a peripheral station of the foundation pit by adopting a long-arm excavator, loading a TAC320 excavator, paving an HDPE film on the surface of the next layer of polluted soil after the upper layer of polluted soil is excavated, and then excavating peripheral clean soil, wherein the second working area is an organic polluted foundation pit, the excavation mode is the same as that of the first working area, and the three working areas contain more phosphorus and are more serious in pollution, so that the periphery of the foundation pit is sealed by Lassen steel piles in the early stage of excavation, wherein the Lassen steel piles are constructed by adopting a crawler excavator, before piling, workers are required to check the pile body one by one, remove rust which is seriously deformed, the steel piles which are seriously deformed can not be used until the repair is qualified after the repair is finished, and the repair is still qualified, and the repair is required to be disabled; before piling, grease is smeared in a locking notch of the Larson steel pile, so that the pile bodies are convenient to drive and pull out, the inclination of each pile body is required to be measured and monitored to be not more than 2% in the inserting and driving process, when the inclination is overlarge, the Larson steel pile is required to be aligned by using a pull Ji Fangfa, if the Larson steel pile cannot be aligned, the Larson steel pile is required to be lifted and driven, after the Larson steel pile is completely driven, larson steel piles on two sides of an open channel are respectively connected into a whole by using H200 by 11 by 19mm I-steel, the Larson steel piles are required to be respectively connected into a whole at the position about 1.5m below the pile top, then the Larson steel piles on two sides are symmetrically supported by using a movable section at intervals of 5m, the Larson steel piles on two sides are required to be screwed up by using a movable section, so as to ensure the verticality of the Larson steel pile and the working face of a foundation pit excavation, the change condition of the Larson pile is required to be observed at any time in the foundation pit excavation process, and if obvious capsizing or uplift states are required to be immediately increased by workers at the symmetrical supporting positions.
Preferably, during construction of the Larson steel pile, a Larson steel pile driving position line is measured according to the requirement of the width of the excavation section of the polluted foundation pit, and marking is carried out.
Preferably, the Larson steel piles are driven by a crawler-type excavator, and the inclination of each Larson steel pile is not more than 2% in the Larson steel pile inserting and driving process; after the Larson steel piles are applied, H200 multiplied by 11 multiplied by 19mm I-steel is used for respectively connecting Larson steel piles on two sides of the open channel into a whole, welding the Larson steel piles firmly by welding rods, and then symmetrically supporting the steel sheet piles on two sides by using hollow round steel materials at intervals of 5 m.
Example IV
Referring to fig. 4-6, in the first embodiment, the steel sheet pile assembly includes a first steel sheet pile welded to the steel pipe column, and a second steel sheet pile screwed to the first steel sheet pile, and a plurality of buffer springs and air filling columns are arranged between the first steel sheet pile and the second steel sheet pile; the detection assembly comprises a plurality of infrared sensors arranged on the lower end surface of the cross rod; the alarm assembly comprises a buzzer and a singlechip which are arranged on the lower end surface of the cross rod; the singlechip, the buzzer and the infrared sensor are electrically connected; the top of diaphragm is equipped with the photovoltaic board.
The corresponding buffer springs and the corresponding air filling columns are arranged between the first steel sheet pile and the second steel sheet pile, so that the anti-seismic performance of the steel sheet pile assembly is effectively enhanced, and after the steel sheet pile assembly is deformed, the steel sheet pile assembly can be effectively detected through the infrared sensor; and through setting up the photovoltaic board, can effectively supply power to this equipment, turn into the electric energy with solar energy, when practicing thrift manufacturing cost, the security when having improved steel sheet pile subassembly and used.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (7)
1. A polluted foundation pit supporting and rapid excavation construction method is characterized in that: comprising
Step one: before the polluted foundation pit is excavated, cleaning the periphery of the polluted foundation pit, leveling a site, cleaning slurry on a construction site, and then measuring and lofting the construction site; dividing the polluted foundation pit into a first work area, a second work area and a third work area;
step two: a water retaining wall formed by concrete pouring is arranged on the periphery of the polluted foundation pit, and the water retaining wall is arranged along the periphery of the polluted foundation pit in a full length mode;
step three: the polluted foundation pit is used for respectively detecting the soil on the pit walls of the foundation pit in the first working area, the second working area and the third working area in the excavation process; wherein the first working area is a heavy metal pollution foundation pit, the second working area is an organic pollution foundation pit, and the third working area is a phosphorus pollution foundation pit;
step four: adopting a slope-releasing excavation mode in the construction process of the polluted foundation pit, wherein slope protection measures are net hanging and anchor spraying; the polluted foundation pit is provided with a plurality of steel pipe columns, steel sheet pile assemblies are connected between the plurality of steel pipe columns, each steel sheet pile assembly comprises a first steel sheet pile welded on the steel pipe column and a second steel sheet pile connected on the first steel sheet pile in a threaded manner, and a plurality of buffer springs and air filling columns are arranged between the first steel sheet pile and the second steel sheet pile; the steel pipe column comprises a steel pipe column body, wherein a steel pipe column is arranged at the top end of the steel pipe column body, a transverse plate is arranged at the top end of the steel pipe column body, a detection assembly and an alarm assembly are respectively arranged on the lower end face of the transverse plate, the detection assembly comprises a plurality of infrared sensors arranged on the lower end face of the transverse plate, the alarm assembly comprises a buzzer and a singlechip which are arranged on the lower end face of the transverse plate, and the singlechip, the buzzer and the infrared sensors are electrically connected; the top of the transverse plate is provided with a photovoltaic plate;
step five: reserving protective films on the slope surface when excavating the first working area, the second working area and the third working area, manually carrying out slope surface trimming by matching with machinery, and carrying out slope surface supporting in time after finishing slope surface trimming; until the foundation pit is excavated to the bottom of the foundation pit; the first work area and the second work area are firstly subjected to pollution boundary and excavation boundary measurement paying-off in the excavation process, then subjected to multi-layer excavation of polluted soil, and simultaneously subjected to excavation and support in the excavation process; after the upper layer of polluted soil is excavated, paving HDPE film separation on the surface of the lower layer of polluted soil; the three-work area is a heavy pollution area, the periphery of the heavy pollution area is sealed by Larson steel piles, excavation is not carried out, the tops of the Larson steel piles are exposed out of the ground for 50cm, a lock catch waist beam is arranged on the outer side of each Larson steel pile, then reinforcement is carried out, and point distribution monitoring is carried out; the Larson steel piles are driven by a crawler-type excavator, the inclination of each Larson steel pile is not more than 2% in the Larson steel pile inserting and driving process, and after the Larson steel piles are driven, larson steel piles on two sides of an open channel are respectively connected into a whole by using I-shaped steel and are firmly welded by using welding rods;
step six: leveling and cleaning broken stone on the substrate of the polluted foundation pit, and checking and accepting the plane position of the substrate, the elevation of the substrate and the geology of the substrate of the polluted foundation pit after leveling and cleaning broken stone.
2. The method for supporting and rapidly excavating a polluted foundation pit according to claim 1, wherein the method comprises the following steps: in the fourth step, a total station is adopted as a measuring and lofting instrument before construction, and excavation edges are drawn; in the excavation process, a large excavator and a small excavator are matched for excavation, and a closed dump truck is used for deslagging; and when the slope is excavated to 20cm, the slope is repaired by manual cooperation, and soil nailing construction is performed.
3. The method for supporting and quickly excavating a polluted foundation pit according to claim 2, which is characterized in that: the soil nails are cement mortar soil nails, and a construction mode of grouting firstly and then inserting the soil nails is adopted.
4. The method for supporting and rapidly excavating a polluted foundation pit according to claim 1, wherein the method comprises the following steps: in the fourth step, the polluted foundation pit is excavated by adopting 1:1 slope-releasing excavation, and each layer of excavation is carried out once net hanging and spraying protection until the pit bottom.
5. The method for supporting and rapidly excavating a polluted foundation pit according to claim 1, wherein the method comprises the following steps: in the fourth step, the concrete is sprayed on the concrete surface layer, then the fine stone concrete is sprayed, and the distance between the spray head and the sprayed surface is 0.6-1.2 m.
6. The method for supporting and rapidly excavating a polluted foundation pit according to claim 1, wherein the method comprises the following steps: and in the construction process of the Larson steel pile, measuring a Larson steel pile driving position line according to the requirement of the width of the excavation section of the polluted foundation pit, and marking.
7. The method for supporting and rapidly excavating a polluted foundation pit according to claim 1, wherein the method comprises the following steps: in the third step, soil conditions of the pit walls of the first work area, the second work area and the third work area are detected by adopting a soil detection sensor.
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