CN113356221A - 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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- CN113356221A CN113356221A CN202110741591.8A CN202110741591A CN113356221A CN 113356221 A CN113356221 A CN 113356221A CN 202110741591 A CN202110741591 A CN 202110741591A CN 113356221 A CN113356221 A CN 113356221A
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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 construction method for supporting and quickly excavating a polluted foundation pit, 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 of a construction site, and 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 the polluted foundation pit, adopting concrete pouring molding, and arranging along the whole length of the periphery of the polluted foundation pit; step three: and respectively detecting the pit wall soil of the foundation pits in the first work area, the second work area and the third work area in the excavation process of the foundation pit, wherein the first work area is a heavy metal polluted foundation pit, and the second work area is an organic polluted foundation pit. The method solves the problems that the existing method for excavating the polluted foundation pit is low in safety, low in excavation speed and incapable of detecting the pit wall of the foundation pit, and a reasonable construction method is formulated according to the pollution condition of soil, so that the construction period is increased invisibly, and the construction efficiency is reduced.
Description
Technical Field
The invention relates to the technical field of civil engineering, in particular to a construction method for supporting and quickly excavating a polluted foundation pit.
Background
The existing restoration method of the heavy metal polluted site mainly comprises burying, phytoremediation, bioremediation, soil leaching, solidification and stabilization, various integrated restoration technologies and the like, wherein the burying method is to dig out the polluted soil, place the dug polluted soil in a designated place and cover the dug polluted soil with the unpolluted soil, the method is simple to operate, but occupies the land, is easy to leak and pollute the surrounding environment, and transfers the pollution to the buried site, the phytoremediation and bioremediation technology mainly fixes the heavy metal pollutants in plants or organisms, and then extracts the heavy metals by using various separation technologies, the method is only used for the treatment of the agricultural polluted soil, is difficult to improve the strength of foundation soil, is influenced by the growth cycle of the plants or organisms, has long restoration time, and is not suitable for the restoration of the urban industrial polluted site;
the polluted site restoration technology can be divided into an in-situ restoration technology and an ex-situ restoration technology according to restoration sites, the in-situ restoration technology does not move polluted soil, the polluted site is directly restored in situ, and the method has the characteristics of good effect, small secondary pollution and the like; the ex-situ remediation technology is characterized in that the polluted soil is excavated and treated in situ or after transportation, the remediation period is short, the remediation effect is more controllable than that of in-situ remediation, but secondary pollution is easily caused in the excavation process, and the cost for excavation and transportation is high for large-area polluted soil;
in the Chinese patent application CN108746171A, the application mainly solves the problems of complex working procedures and high cost of the existing excavation process, but in the actual excavation process, a foundation pit support is not added, so that a certain potential safety hazard exists in the excavation process;
in the chinese patent application CN101773928A, this application discloses a treatment method for in-situ solidification and isolation of heavy metal industrial contaminated site, but this method only solidifies the pollutants in the soil inside the contaminated site, and does not change its state or form, resulting in still having a large pollution risk;
therefore, a construction method for supporting and quickly excavating a polluted foundation pit is provided.
Disclosure of Invention
The invention provides a construction method for supporting and quickly excavating a polluted foundation pit to solve the technical problems.
In order to achieve the purpose, the invention provides the following technical scheme:
a construction method for supporting and quickly excavating polluted foundation pit includes
The method comprises the following steps: before the polluted foundation pit is excavated, cleaning the periphery of the polluted foundation pit, leveling the site, cleaning slurry of 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 pouring concrete is arranged at the periphery of the polluted foundation pit and is arranged along the whole length of the periphery of the polluted foundation pit;
step three: the contaminated foundation pit detects the pit wall soil of the foundation pit in the first working area, the second working area and the third working area respectively in the excavation process; 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;
step four: the polluted foundation pit adopts a slope-releasing excavation mode in the construction process, and the slope surface protection measure is net-hanging anchor spraying; arranging a plurality of steel pipe columns on the pollution foundation pit, and connecting steel plate pile components among the plurality of steel pipe columns; the top end of the steel pipe column is provided with a transverse plate, and the lower end surface of the transverse plate is provided with a detection assembly and an alarm assembly respectively;
step five: reserving a protective film on the slope when the first working area, the second working area and the third working area are excavated, manually matching with machinery to carry out slope finishing, and timely carrying out slope support after the slope finishing is finished; until the bottom of the foundation pit is excavated;
step six: and leveling and gravel cleaning are carried out on the base of the polluted foundation pit, and the base plane position, the base elevation and the base geology of the polluted foundation pit after leveling and gravel cleaning are checked and accepted.
The method can detect the pit wall soil in the excavation process, and adopt different construction methods according to different detection results, so that the foundation pit can be effectively and quickly excavated, a better construction effect is achieved, and meanwhile, the method has higher 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 in threaded connection with the first steel sheet pile, and a plurality of buffer springs and inflatable 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 single chip microcomputer which are arranged on the lower end face of the cross rod; the single chip microcomputer, the buzzer and the infrared sensor are electrically connected; and a photovoltaic panel is arranged at the top of the transverse plate.
Wherein the breakwater mainly is in order to ensure during the rainstorm in rainy season, place rainwater can not flow into the foundation ditch and cause the loss, the place and the foundation ditch are along the sump pit that escape canal every 50m arranged all around, as supplementary drainage facility during the rainstorm, and set up the precipitation well in the foundation ditch, adopt the positive circulation rig pore-forming in-process of pore-forming, after drilling, put 2m deep gravel or well coarse sand at the bottom of the hole first, then hang and put the strainer, the strainer adopts phi 400/300mm cement gravel strainer, the outer packing 60 mesh nylon gravel strainerAnd a net is placed into the well by using a truck crane, the well pipe is vertically placed in the middle of the well, the top of the well pipe is higher than the ground by about 50cm, the well pipe is lowered to the designed depth, and after the water filtering well pipe is placed into the hole, a fine gravel filter material with the particle size of 3-7 mm is timely filled between the well pipe and the wall of the hole. The filter material must meet the grading requirement, screen out the particles except the upper and lower limits of the designed gravel specification, the qualification rate is more than 90%, the impurity content is not more than 3%, use spade unloading, in order to prevent the stratification from being uneven and impact the well pipe, fill the filter material and once finish continuously, fill to 1m under the well head from the bottom, the upper portion adopts the clay without sandstone to backfill and tamp and seal, the last step is the well washing, the main purpose of well washing lies in clearing away the mud that stops in the hole and permeable stratum and the mud of the hole wall, dredge the permeable stratum, and form good inverted filter around the well, adopt the pressure of 0.8Mpa, the displacement is 9m Mpa, adopt the mud of the hole wall to be good3And (5) washing the well by combining a/min air compressor and a submersible pump until clear water is pumped out. The difference of water pumping water inflow amounts of the front and the rear of the well washing is less than 15%, and the sediment in the well does not rise after the well washing.
Preferably, in the fourth step, a total station is adopted as a measuring and lofting instrument before construction, and an excavation side line is drawn; in the excavation process, a large excavator and a small excavator are adopted to carry out excavation in a matched mode, and the sealed type dump truck carries out slag discharging; and when the slope surface is excavated to 20cm, manually repairing the slope and performing soil nailing construction.
Preferably, the soil nails are cement mortar soil nails, and a construction mode of firstly grouting and then inserting the soil nails is adopted.
Wherein the permanent support soil nail which is firstly grouted is inserted immediately after the drill hole is filled with the grout; the permanent support soil nail of back slip casting carries out the slip casting immediately after the soil nail installation, insert the slip casting pipe to the hole bottom earlier, then withdraw from 50 ~ 100mm, begin the slip casting, the slip casting pipe is drawn out at the uniform velocity slowly along with the injection of mortar, insert soil nail immediately after full of the slip casting in the drilling, soil nail hole slip casting must closely knit, the downthehole mortar that fills up after the soil nail installation, the length in the body of rod insert hole is not less than 95% of design length, after the soil nail installation, before the mortar solidifies, must not strike, collide and draw the soil nail, keep 48h soil nail at least not disturbed.
Preferably, in the fourth step, the polluted foundation pit is excavated by 1:1 slope excavation, and once net hanging and spraying protection is carried out to the bottom of the pit every layer of excavation.
Wherein, in the excavation process of the foundation pit, excavation is strictly carried out according to a designed slope ratio, over excavation is strictly forbidden, the slope is repaired in time, the flatness of the slope surface is ensured, the excavation depth and length of each step are reduced at the part with poor slope stability, the distance between the dowel bars is 1m, and the dowel bars are arranged in a quincunx shape; the method is characterized in that a total station is adopted to discharge point locations, the point locations are marked, slope joint bars are C20 steel bars, the length is 3m, the inserted slope joint bars are perpendicular to a slope surface, a grid with the diameter of 150 x 150 is adopted, the thickness of a protective layer of a steel bar net facing the soil surface 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 quincunx manner, the arrangement density is 2000 x 2000, and a Luoyang shovel is adopted to dig the soil body during installation so as to prevent blockage of a water drain hole.
Preferably, in the fourth step, the concrete is sprayed to the concrete surface layer firstly, and then the fine aggregate concrete is sprayed, wherein the distance between the spray head and the sprayed surface is 0.6-1.2 m.
The inclined planes with an angle of 45 degrees are formed between the middle segments and between the layers, the concrete spraying equipment adopts an air compressor, and the air volume of the air compressor is not less than 9m3The air pressure is 0.2-0.5 Mpa, the water pressure of the 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 sprayed with water for maintenance for one circle.
Preferably, in the fifth step, in the first working area and the second working area, during the excavation process, firstly, the polluted boundary and the excavation boundary are measured and set out, the polluted soil is excavated in multiple layers, and during the excavation process, the supporting is carried out while excavating; after the upper layer of polluted soil is excavated, laying an HDPE film on the surface of the lower layer of polluted soil for separation;
the method comprises the following steps that a duplex region is a heavy pollution region, the periphery of the heavy pollution region is sealed by Larsen steel piles, excavation is not conducted for the time, the pile tops of the Larsen steel piles are exposed out of the ground by 50cm, lock catch waist beams are arranged on the outer sides of the Larsen steel piles, and then reinforcing and point distribution monitoring are conducted.
The first work area is a heavy metal polluted foundation pit, during the excavation process, firstly, the polluted boundary and the excavation boundary measurement paying-off are carried out, then, the polluted soil excavation is carried out firstly, a long-arm excavator is adopted to directly excavate at the peripheral stations of the foundation pit, a TAC320 excavator is adopted to load, after the upper layer of polluted soil is excavated, a HDPE film is paved on the surface of the lower layer of polluted soil for separation, then the surrounding clean soil is excavated, wherein the secondary work area is an organic pollution foundation pit, the excavation mode is the same as that of the primary work area, and the three work areas contain more phosphorus and cause more serious pollution, so that the periphery is sealed by Larsen steel piles in the early stage of excavation, the Larsen steel pile is driven by a crawler excavator, before driving, workers are required to check the pile body one by one, rust marks deducted by chain are removed, steel plate piles with serious deformation can be used after being repaired and integrated to be qualified, and the steel plate piles which are still unqualified after being repaired are forbidden; before piling, coating grease in a locking port of a Larsen steel pile to facilitate the driving and pulling of the pile body, measuring and monitoring the inclination of each pile body to be not more than 2% in the inserting and driving process, aligning by using a leveling method when the inclination is overlarge, pulling and re-driving if the inclination cannot be adjusted, in order to avoid that the Larsen steel pile is squeezed down by lateral soil pressure after excavation of foundation pit, after the Larsen steel pile is driven, connecting the Larsen steel piles at two sides of an open channel into a whole by using H200 by 11 by 19mm I-steel respectively, positioning the Larsen steel piles at about 1.5m below the pile top, using electric welding rods to strain the Larsen steel piles, then using 200 by 12mm hollow round steel materials at intervals of 5m, using movable joints to symmetrically support the Larsen steel piles at two sides, screwing nuts of the movable joints during supporting to ensure the verticality and the excavation working face of the Larsen steel pile, and excavating the foundation pit in the process, the change condition of the Larsen pile needs to be observed at any time, and if the overturn or uplift state is obvious, a worker needs to immediately add symmetrical support at the overturn or uplift position.
Preferably, the driving position line of the Larsen steel pile is measured and marked according to the width requirement of the excavation section of the polluted foundation pit in the construction process of the Larsen steel pile.
Preferably, the Larsen steel piles are driven by a crawler excavator, and the inclination of each Larsen steel pile is not more than 2% in the inserting and driving process of the Larsen steel piles; and after the Larsen steel piles are driven, connecting the Larsen steel piles on two sides of the open channel into a whole by using I-shaped steel, and firmly welding the Larsen steel piles by using welding rods.
Preferably, in the third step, a soil detection sensor is adopted to detect the soil conditions of the foundation pit walls of the first work area, the second work area and the third work area.
Compared with the prior art, the invention has the following beneficial effects:
1. the method is suitable for treating the severely polluted site, and the method has the advantages of high excavation speed and high safety performance; 2. the process equipment investment and the operating cost are low, and the position of a treatment site is not limited; 3. the invention adopts closed measure construction, has simpler construction steps and safe and reliable construction process, can effectively avoid the diffusion of pollutants in a 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 the foundation pit construction process of the present invention;
FIG. 2 is a flow chart of the soil nailing construction process of the present invention;
FIG. 3 is a flow chart of the Larsen steel pile construction process of the invention;
FIG. 4 is a schematic front view of a Larsen steel sheet according to the present invention;
FIG. 5 is a top view of the Larsen steel plate and cross bar assembly of the present invention;
FIG. 6 is a plan view of a Larsen steel sheet according to the present invention.
Description of the drawings: 1. steel pipe columns; 2. a first steel sheet pile; 3. a second steel sheet pile; 4. a buffer spring; 5. an inflatable column; 6. a transverse plate; 7. an infrared sensor; 8. a photovoltaic panel; 9. and an alarm device.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example one
Referring to fig. 1, a construction method for supporting and rapidly excavating a contaminated foundation pit includes
The method comprises the following steps: before the polluted foundation pit is excavated, cleaning the periphery of the polluted foundation pit, leveling the site, cleaning slurry of a construction site, and 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 the polluted foundation pit, adopting concrete pouring molding, and arranging the water retaining wall along the whole length of the periphery of the polluted foundation pit; pouring concrete to form the water retaining wall, wherein the height of the wall is 30cm, and the thickness of the wall is 10 cm; 1 water collecting well with the length of 1m multiplied by 1m is arranged at intervals of 50cm around the polluted foundation pit along the drainage ditch; and a catch drain of 0.3-0.3 m is arranged at the position of the top of the polluted foundation pit, which is at least 3m away from the excavation crest line of the polluted foundation pit.
Step three: the method comprises the following steps that (1) contaminated foundation pits are detected in the excavation process of foundation pits of a first working area, a second working area and a third working area respectively, wherein the first working area is a heavy metal contaminated foundation pit, the second working area is an organic contaminated foundation pit, and the third working area is a phosphorus contaminated foundation pit; if the soil pollution is detected to be serious, the excavation is continued, otherwise, the slope is released;
step four: adopting a slope-releasing excavation mode in the construction process of the polluted foundation pit, releasing the slope according to a slope coefficient of 1:1.2 if the depth of the polluted foundation pit is 0-4m, and adopting a slope surface protection measure of net hanging anchor spraying; if the depth of the polluted foundation pit is below 6m, slope releasing is carried out according to the gradient coefficient of 1:1.5, a plurality of steel pipe columns are arranged on the polluted foundation pit, and steel plate pile components are connected among the plurality of steel pipe columns; the top end of the steel pipe column is provided with a transverse plate, and the lower end surface of the transverse plate is respectively provided with a detection assembly and an alarm assembly;
step five: reserving a protective film on the slope when a first work area, a second work area and a third work area are excavated, manually matching with machinery to trim the slope, and timely supporting the slope after the slope is trimmed; after the slope support reaches the strength required by the specification, performing next-layer excavation until the slope support reaches the bottom of the foundation pit;
step six: leveling and cleaning broken stones for the base of the polluted foundation pit, and checking and accepting the base plane position, the base elevation and the base geology of the polluted foundation pit after leveling and cleaning the broken stones.
WhereinThe water retaining wall is mainly used for ensuring that rainwater on a site cannot flow into a foundation pit to cause loss in rainy seasons, water collecting wells are arranged at intervals of 50m along drainage ditches at the periphery of the site and the foundation pit and serve as auxiliary pumping and drainage facilities in the rainy seasons, a precipitation well is arranged in the foundation pit, a forward circulation drilling machine is adopted for hole forming in the hole forming process, after drilling is finished, 2m deep gravels or medium coarse sand are placed at the bottom of a hole, then a water filtering pipe is hung and placed, 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 placed into the well by a truck crane, the well pipe is placed vertically and is positioned in the middle of the well hole, the top of the water filtering pipe is 50cm higher than the ground, reinforcing measures are taken, the well pipe is lowered to the designed depth, and after the water filtering pipe is placed into the hole, a fine filtering material with the grain size of 3-7 mm is timely filled between the well pipe and the wall. The filter material must meet the grading requirement, screen out the particles except the upper and lower limits of the designed gravel specification, the qualification rate is more than 90%, the impurity content is not more than 3%, use spade unloading, in order to prevent the stratification from being uneven and impact the well pipe, fill the filter material and once finish continuously, fill to 1m under the well head from the bottom, the upper portion adopts the clay without sandstone to backfill and tamp and seal, the last step is the well washing, the main purpose of well washing lies in clearing away the mud that stops in the hole and permeable stratum and the mud of the hole wall, dredge the permeable stratum, and form good inverted filter around the well, adopt the pressure of 0.8Mpa, the displacement is 9m Mpa, adopt the mud of the hole wall to be good3And (5) washing the well by combining a/min air compressor and a submersible pump until clear water is pumped out. The difference of water pumping water inflow amounts of the front and the rear of the well washing is less than 15%, and the sediment in the well does not rise after the well washing.
Preferably, in the fourth step, a total station is adopted as a measuring and lofting instrument before construction, and an excavation side line is drawn; in the excavation process, a large excavator and a small excavator are adopted to carry out excavation in a matched mode, and the sealed type dump truck carries out slag discharging; and when the slope surface is excavated to 20cm, manually repairing the slope and performing soil nailing construction.
Example two
Referring to fig. 2, in the construction method for supporting and quickly excavating the polluted foundation pit, preferably, the soil nails are cement mortar soil nails, and mainly adopt 16mm three-level hot rolled steel bars and M30 cement mortar for full-length grouting, and a construction mode of grouting first and then inserting the soil nails is adopted; prying and removing pumice on the side slope, cleaning the rock surface, and arranging the drilling position; drilling a mortar soil nail with the soil nail length less than 6m by adopting an YT-28 hand pneumatic drill, and mounting the soil nail after grouting; when the length of the soil nail is more than 6m, a YG80 guide rail type rock drill is adopted for drilling, and the soil nail is firstly installed and then grouting is carried out; and after the drilling is finished, washing the hole by using high-pressure air water, and blowing out water in the hole.
Wherein the permanent support soil nail which is firstly grouted is inserted immediately after the drill hole is filled with the grout; the permanent support soil nail of back slip casting carries out the slip casting immediately after the soil nail installation, insert the slip casting pipe to the hole bottom earlier, then withdraw from 50 ~ 100mm, begin the slip casting, the slip casting pipe is drawn out at the uniform velocity slowly along with the injection of mortar, insert soil nail immediately after full of the slip casting in the drilling, soil nail hole slip casting must closely knit, the downthehole mortar that fills up after the soil nail installation, the length in the body of rod insert hole is not less than 95% of design length, after the soil nail installation, before the mortar solidifies, must not strike, collide and draw the soil nail, keep 48h soil nail at least not disturbed.
EXAMPLE III
Referring to fig. 3, a construction method for supporting and rapidly excavating a polluted foundation pit, preferably, in the fifth step, in the excavation process, a polluted boundary and an excavation boundary are firstly measured and set off in a first working area and a second working area, the polluted soil is excavated in multiple layers, the supporting and the excavating are carried out while excavating, and the excavating mode adopts vertical layering, longitudinal segmentation and support following excavation; after the upper layer of polluted soil is excavated, laying a HDPE film on the surface of the lower layer of polluted soil for separation, excavating the peripheral clean soil, and placing a slope and a pit wall for soil detection and support;
the method comprises the following steps that a triplex region is a heavy pollution region, the periphery of the heavy pollution region is sealed by Larsen steel piles, excavation is not carried out temporarily, the tops of the Larsen steel piles are exposed to 50cm above the ground, lock catch waist beams are arranged on the outer sides of Larsen steel plates, then opposite sides are oppositely pulled and reinforced, concrete with the thickness of 50cm is fully poured on the surface of the square Larsen steel piles, point distribution monitoring is carried out, meanwhile, foundation pit dewatering wells are constructed, foundation pit dewatering is carried out, after the dewatering wells are completed, pay-off is carried out on the excavation boundary of the triplex region, and then polluted soil excavation is carried out;
the first work area is a heavy metal polluted foundation pit, during the excavation process, firstly, the polluted boundary and the excavation boundary measurement paying-off are carried out, then, the polluted soil excavation is carried out firstly, a long-arm excavator is adopted to directly excavate at the peripheral stations of the foundation pit, a TAC320 excavator is adopted to load, after the upper layer of polluted soil is excavated, a HDPE film is paved on the surface of the lower layer of polluted soil for separation, then the surrounding clean soil is excavated, wherein the secondary work area is an organic pollution foundation pit, the excavation mode is the same as that of the primary work area, and the three work areas contain more phosphorus and cause more serious pollution, so that the periphery is sealed by Larsen steel piles in the early stage of excavation, the Larsen steel pile is driven by a crawler excavator, before driving, workers are required to check the pile body one by one, rust marks deducted by chain are removed, steel plate piles with serious deformation can be used after being repaired and integrated to be qualified, and the steel plate piles which are still unqualified after being repaired are forbidden; before piling, coating grease in a locking port of a Larsen steel pile to facilitate the driving and pulling of the pile body, measuring and monitoring the inclination of each pile body to be not more than 2% in the inserting and driving process, aligning by using a leveling method when the inclination is overlarge, pulling and re-driving if the inclination cannot be adjusted, in order to avoid that the Larsen steel pile is squeezed down by lateral soil pressure after excavation of foundation pit, after the Larsen steel pile is driven, connecting the Larsen steel piles at two sides of an open channel into a whole by using H200 by 11 by 19mm I-steel respectively, positioning the Larsen steel piles at about 1.5m below the pile top, using electric welding rods to strain the Larsen steel piles, then using 200 by 12mm hollow round steel materials at intervals of 5m, using movable joints to symmetrically support the Larsen steel piles at two sides, screwing nuts of the movable joints during supporting to ensure the verticality and the excavation working face of the Larsen steel pile, and excavating the foundation pit in the process, the change condition of the Larsen pile needs to be observed at any time, and if the overturn or uplift state is obvious, a worker needs to immediately add symmetrical support at the overturn or uplift position.
Preferably, the driving position line of the Larsen steel pile is measured and marked according to the width requirement of the excavation section of the polluted foundation pit in the construction process of the Larsen steel pile.
Preferably, the Larsen steel piles are driven by a crawler-type excavator, and the inclination of each Larsen steel pile is not more than 2% in the inserting and driving process of the Larsen steel piles; after the Larsen steel piles are driven, H200 multiplied by 11 multiplied by 19mm I-steel is used for respectively connecting the Larsen steel piles at two sides of the open channel into a whole, electric welding rods are used for firmly welding the Larsen steel piles, and then hollow round steel materials are used for symmetrically supporting the steel plate piles at two sides by a special movable joint every 5 m.
Example four
Referring to fig. 4-6, in the embodiment, on the basis of 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 inflatable columns are disposed 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 component 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 spring and the corresponding inflatable column 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, the steel sheet pile assembly can be effectively detected through the infrared sensor after being deformed, when the deformed part of the steel sheet pile touches the infrared sensor, the infrared sensor transmits detection data to a single chip microcomputer of an alarm device, and a buzzer is controlled by the single chip microcomputer to give a buzzing alarm so as to remind a worker in time; 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 the steel sheet pile subassembly and using.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (10)
1. A construction method for supporting and quickly excavating a polluted foundation pit is characterized by comprising the following steps: comprises that
The method comprises the following steps: before the polluted foundation pit is excavated, cleaning the periphery of the polluted foundation pit, leveling the site, cleaning slurry of 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 pouring concrete is arranged at the periphery of the polluted foundation pit and is arranged along the whole length of the periphery of the polluted foundation pit;
step three: the contaminated foundation pit detects the pit wall soil of the foundation pit in the first working area, the second working area and the third working area respectively in the excavation process; 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;
step four: the polluted foundation pit adopts a slope-releasing excavation mode in the construction process, and the slope surface protection measure is net-hanging anchor spraying; arranging a plurality of steel pipe columns on the pollution foundation pit, and connecting steel plate pile components among the plurality of steel pipe columns; the top end of the steel pipe column is provided with a transverse plate, and the lower end surface of the transverse plate is provided with a detection assembly and an alarm assembly respectively;
step five: reserving a protective film on the slope when the first working area, the second working area and the third working area are excavated, manually matching with machinery to carry out slope finishing, and timely carrying out slope support after the slope finishing is finished; until the bottom of the foundation pit is excavated;
step six: and leveling and gravel cleaning are carried out on the base of the polluted foundation pit, and the base plane position, the base elevation and the base geology of the polluted foundation pit after leveling and gravel cleaning are checked and accepted.
2. The construction method for supporting and rapidly excavating the polluted foundation pit as claimed in claim 1, wherein the construction method comprises the following steps: the steel sheet pile assembly comprises a first steel sheet pile welded on the steel pipe column and a second steel sheet pile in threaded connection with the first steel sheet pile, and a plurality of buffer springs and inflatable 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 single chip microcomputer which are arranged on the lower end face of the cross rod; the single chip microcomputer, the buzzer and the infrared sensor are electrically connected; and a photovoltaic panel is arranged at the top of the transverse plate.
3. The construction method for supporting and rapidly excavating the polluted foundation pit as claimed in claim 1, wherein the construction method comprises the following steps: in the fourth step, a total station is adopted as a measuring and lofting instrument before construction, and an excavation side line is drawn; in the excavation process, a large excavator and a small excavator are adopted to carry out excavation in a matched mode, and the sealed type dump truck carries out slag discharging; and when the slope surface is excavated to 20cm, manually repairing the slope and performing soil nailing construction.
4. The construction method for supporting and rapidly excavating the polluted foundation pit as claimed in claim 3, wherein the construction method comprises the following steps: the soil nails are cement mortar soil nails, and a construction mode of grouting first and then inserting the soil nails is adopted.
5. The construction method for supporting and rapidly excavating the polluted foundation pit as claimed in claim 1, wherein the construction method comprises the following steps: in the fourth step, the polluted foundation pit is excavated by 1:1 slope excavation, and once net hanging and spraying protection is carried out to the bottom of the pit every time one layer is excavated.
6. The construction method for supporting and rapidly excavating the polluted foundation pit as claimed in claim 1, wherein the construction method comprises the following steps: and in the fourth step, spraying concrete to spray the concrete surface layer firstly, and then spraying fine aggregate concrete, wherein the distance between a spray head and the sprayed surface is 0.6-1.2 m.
7. The construction method for supporting and rapidly excavating the polluted foundation pit as claimed in claim 1, wherein the construction method comprises the following steps: in the fifth step, in the excavation process, firstly carrying out measurement and paying-off on a polluted boundary and an excavation boundary in the first working area and the second working area, carrying out multilayer excavation on polluted soil, and carrying out excavation and supporting in the excavation process; after the upper layer of polluted soil is excavated, laying an HDPE film on the surface of the lower layer of polluted soil for separation;
the method comprises the following steps that a duplex region is a heavy pollution region, the periphery of the heavy pollution region is sealed by Larsen steel piles, excavation is not conducted for the time, the pile tops of the Larsen steel piles are exposed out of the ground by 50cm, lock catch waist beams are arranged on the outer sides of the Larsen steel piles, and then reinforcing and point distribution monitoring are conducted.
8. The construction method for supporting and rapidly excavating the polluted foundation pit as claimed in claim 7, wherein the construction method comprises the following steps: and in the construction process of the Larsen steel pile, measuring a driving position line of the Larsen steel pile according to the width requirement of the excavation section of the polluted foundation pit, and marking the driving position line.
9. The method for supporting and rapidly excavating the polluted foundation pit according to claim 8, wherein the method comprises the following steps: the Larsen steel piles are driven by a crawler-type excavator, and the inclination of each Larsen steel pile is not more than 2% in the inserting and driving process of the Larsen steel piles; and after the Larsen steel piles are driven, connecting the Larsen steel piles on two sides of the open channel into a whole by using I-shaped steel, and firmly welding the Larsen steel piles by using welding rods.
10. The construction method for supporting and rapidly excavating the polluted foundation pit as claimed in claim 1, wherein the construction method comprises the following steps: and in the third step, detecting the soil conditions of the foundation pit walls of the first work area, the second work area and the third work area by adopting a soil detection sensor.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107316421A (en) * | 2017-08-16 | 2017-11-03 | 河海大学常州校区 | The night Material Management System and its application method in a kind of construction site |
| CN111456019A (en) * | 2020-04-10 | 2020-07-28 | 北京场道市政工程集团有限公司 | Safe construction method for foundation pit excavation |
| CN112281857A (en) * | 2020-10-19 | 2021-01-29 | 中铁六局集团有限公司 | Deep foundation pit excavation construction method |
| CN112695763A (en) * | 2020-12-28 | 2021-04-23 | 中国水利水电第七工程局有限公司 | Deep sludge stratum foundation pit excavation method |
| CN113174958A (en) * | 2021-03-24 | 2021-07-27 | 上海宝冶集团有限公司 | Construction method for foundation pit of adjacent road under poor ground condition |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107316421A (en) * | 2017-08-16 | 2017-11-03 | 河海大学常州校区 | The night Material Management System and its application method in a kind of construction site |
| CN111456019A (en) * | 2020-04-10 | 2020-07-28 | 北京场道市政工程集团有限公司 | Safe construction method for foundation pit excavation |
| CN112281857A (en) * | 2020-10-19 | 2021-01-29 | 中铁六局集团有限公司 | Deep foundation pit excavation construction method |
| CN112695763A (en) * | 2020-12-28 | 2021-04-23 | 中国水利水电第七工程局有限公司 | Deep sludge stratum foundation pit excavation method |
| CN113174958A (en) * | 2021-03-24 | 2021-07-27 | 上海宝冶集团有限公司 | Construction method for foundation pit of adjacent road under poor ground condition |
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