CN111676980A - Foundation pit supporting construction method - Google Patents
Foundation pit supporting construction method Download PDFInfo
- Publication number
- CN111676980A CN111676980A CN202010484822.7A CN202010484822A CN111676980A CN 111676980 A CN111676980 A CN 111676980A CN 202010484822 A CN202010484822 A CN 202010484822A CN 111676980 A CN111676980 A CN 111676980A
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- China
- Prior art keywords
- anchor rod
- drilling
- hole
- foundation pit
- construction method
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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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
- 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
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B7/00—Special methods or apparatus for drilling
- E21B7/04—Directional drilling
Abstract
The invention discloses a foundation pit supporting construction method, which comprises the following construction procedures of determining hole positions → selecting a drilling machine → installing the drilling machine → drilling holes → clearing holes → installing anchor rods → checking the pullout resistance of the anchor rods. The construction method provided by the invention is suitable for soft geological and humid climate areas, the cost of drilling is low, the anchor rod body is used as a main medium of foundation pit support, the construction method saves the cost, the damage to the stratum is small, and the construction method has the advantages of high construction speed and short construction period.
Description
Technical Field
The invention relates to the field of engineering construction, in particular to a foundation pit supporting construction method.
Background
The mid-trip of the three gorges reservoir area of the Yangtze river belongs to subtropical monsoon climate, the precipitation is sufficient, after the excavation of the foundation pit is finished, the rock types of the stratum to be supported mainly include mudstone and sandstone, the texture is soft, the climate is humid, if a mode of arranging a transverse support is adopted as a foundation pit supporting scheme, the transverse support is easy to rot due to the effect of the humidity, meanwhile, the method is poor in stability when the stratum with the soft texture is implemented, and therefore a foundation pit supporting mode suitable for the geological condition of the local area and a construction method based on the mode are needed.
Disclosure of Invention
In view of the above, the present invention aims to provide a foundation pit supporting construction method, which uses an anchor rod body as a main medium for foundation pit supporting because of soft geology and low drilling cost in the area.
The purpose of the invention is realized by the following technical scheme:
a foundation pit supporting construction method is characterized in that: the construction method specifically comprises the following steps:
s1: determining hole sites according to the requirements of a design elevation;
s2: selecting a drilling machine based on the category of the anchoring stratum, the bore diameter of the anchor rod, the depth of the anchor rod and the construction site conditions;
s3: according to the stratum conditions, erecting a scaffold meeting the bearing capacity and the stability conditions of the drilling machine to install the drilling machine;
s4: drilling a bolt hole;
s5: continuing stable drilling for 1-2 minutes, and using high-pressure air to completely remove rock powder and water in the hole out of the hole;
s6: checking whether the anchor rod hole meets the design requirement, if so, performing S7, and if not, performing rectification until the design requirement is met;
s7: installing an anchor rod;
s8: and (5) checking the pullout resistance of the anchor rod.
Further, the longitudinal and transverse errors of the anchor rod hole in position during drilling are ensured not to exceed +/-50 mm; the elevation error is not more than +/-100 mm; the inclination angle and the direction of the drill hole meet the design requirements; the allowable error of the inclination angle is +/-1.0 degree; the orientation tolerance is ± 2.0 °.
Furthermore, a dry drilling mode is adopted during drilling, and a water drilling mode is forbidden.
Further, the drill bit used for drilling the anchor rod hole in the step S4 has a drill bit diameter not smaller than the designed anchor rod hole diameter; the actual drilling depth is at least 300mm greater than the design drilling depth.
Further, when it is checked that the pressurized water flows out of the anchor rod hole when the anchor rod hole is cleaned as described in S5, drainage holes are formed around the pressurized water to release the pressure and flow rate of the pressurized water.
Further, the conditions for inspecting the qualification of the anchor rod hole in S6 are as follows: when the drill bit is pushed smoothly, impact or shaking is not generated; the testing and delivering length of the drilling tool meets the designed anchor rod hole depth; the drill is smoothly withdrawn; the phenomena of obvious splashing of dust slag and water are not detected by blowing with high-pressure air.
Further, the S7 specifically includes:
s71: manufacturing an anchor rod body by using a phi 32 steel bar;
s72: arranging a group of steel bar positioning frames every 1-3m along the axial direction of the anchor rod body;
s73: carrying out anti-corrosion treatment on the insertion end of the anchor rod body;
s74: and inserting the anchor rod body into the hole position determined by the S1 according to the design requirement and grouting.
The invention has the beneficial effects that:
the invention provides a foundation pit supporting construction method, which has the advantages of saving cost, having less damage to stratum, along with high construction speed and short construction period because the area has soft geology and lower drilling cost and the anchor rod body is adopted as the main medium of the foundation pit supporting.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof.
Drawings
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings, in which:
FIG. 1 is a flow chart of the present invention.
Detailed Description
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the preferred embodiments are illustrative of the invention only and are not limiting upon the scope of the invention.
The purpose of the invention is realized by the following technical scheme:
the embodiment provides a foundation pit supporting construction method, as shown in fig. 1, the construction method specifically comprises the following steps:
s1: determining hole sites according to the requirements of a design elevation;
in the anchor rod construction range, the starting and stopping points are provided with fixing piles by using instruments, the conditions are encrypted in the middle, and the anchor rod is guaranteed not to be damaged in the construction stage. Other holes are measured by taking the fixed pile as a standard steel ruler, the whole section is uniformly lofted,
the position of the anchor rod needs to be lofted according to the length of the equally divided slope, and the distance between the anchor rod and the slope can be properly adjusted. If meeting special difficult place, need to pass through design supervision unit and approve, under the prerequisite of guaranteeing stability and structure safety, suitable relaxation positioning accuracy or adjustment anchor eye location.
S2: a drilling machine is selected based on the category of an anchoring stratum, the aperture of an anchor rod, the depth of the anchor rod and the conditions of a construction site, the anchor rod drilling machine is adopted to drill holes in the stratum, and a root canal drilling technology is adopted in the stratum which is easy to collapse, is broken in the stratum or is soft and full of water and the like and is buried and drilled in a stuck drill.
S3: according to the stratum conditions, a platform is erected by using a scaffold rod with the diameter of 48mm, the platform is fixed with a slope by using an anchor rod, a drilling machine is lifted to the platform by using a tripod, a scaffold meeting the bearing capacity and the stability conditions of the drilling machine is erected to install the drilling machine, the drilling machine is accurately installed and fixed according to the slope measuring and placing hole positions, the machine position is strictly and seriously adjusted, the situation that the longitudinal and transverse errors of the drilled anchor rod hole in position do not exceed +/-50 mm, the elevation error does not exceed +/-100 mm, the inclination angle and the direction of the drilled hole meet the design requirements, the inclination angle allowable error +/-1.0 degrees and the azimuth allowable error +/-2.0 degrees are ensured. The installation of the drilling machine requires to be horizontal and stable, and the drilling machine needs to be checked at any time in the drilling process.
S4: drilling an anchor rod hole, wherein dry drilling is required for drilling the hole, and water drilling is forbidden, so that the engineering geological condition of the side slope rock body is not deteriorated and the bonding property of the hole wall is ensured during anchor rod construction. The drilling speed is strictly controlled according to the performance of the drilling machine and the anchoring stratum, and the drilling hole is prevented from being twisted and reduced, so that the anchoring difficulty or other accidents are avoided.
In the drilling process, on-site construction records are made on stratum changes, drilling states (drilling pressure and drilling speed), underground water and some special conditions of each hole. If the hole collapse and shrinkage phenomena occur, the drilling is stopped immediately, the wall-fixing grouting treatment is carried out in time (the grouting pressure is 0.1-0.2Mpa), and the hole is swept again and drilled after the cement mortar is initially set.
The hole diameter and the hole depth of the drilled hole are required to be not less than the design values, the deviation of the hole opening is less than or equal to +/-50 mm, and the allowable deviation of the hole depth is +200 mm. To ensure the diameter of the anchor rod hole, the diameter of the drill bit used in practice is required to be not smaller than the designed hole diameter. To ensure the bolt hole depth, the actual drilling depth is required to be greater than the design depth of 300 mm.
S5: and (3) continuing stable drilling for 1-2 minutes to prevent the hole bottom from being sharp and extinguishing and the designed hole diameter from being not reached, preventing the hole wall of the drilled hole from being stuck by sediment and water, cleaning the drilled hole wall, and removing rock powder and water in the drilled hole out of the hole by using high-pressure air after the drilling is finished so as to avoid reducing the bonding strength of cement mortar and hole wall rock-soil bodies. Except for anchoring relatively hard and complete rock mass, high-pressure water washing is not required. If pressure-bearing water flows out of the anchor hole, anchor bars and grouting can be arranged below the anchor hole after the water pressure and the water quantity are reduced, and drain holes are arranged at proper positions around the anchor hole for treatment if necessary.
S6: whether the anchor rod hole meets the design requirements is detected, and the detection standard is as follows: the hole inspection is carried out under the condition that a side station is established on site, the drill bit is required to be smoothly pushed in the hole inspection process, impact or shaking is not generated, the inspection and delivery length of the drilling tool meets the designed anchor rod hole depth, the requirement of withdrawing the drilling tool is smooth, and the phenomena of obviously splashing dust slag and water bodies are not generated by blowing inspection with high-pressure air. Meanwhile, the hole position, the inclination angle and the direction of the anchor hole are required to be rechecked, and after all anchor hole construction items are qualified, the anchor hole drilling inspection is qualified. According to the scheme, if the design requirement is met, S7 is carried out, and if the design requirement is not met, rectification is carried out until the design requirement is met;
s7: installing an anchor rod;
s71: manufacturing an anchor rod body by using a phi 32 steel bar;
s72: a group of steel bar positioning frames are arranged every 2m along the axial direction of the anchor rod body;
s73: performing anti-corrosion treatment on the insertion end of the anchor rod body, namely performing two times of treatment by adopting an asphalt isolation layer;
s74: according to the design requirement, the anchor rod body is inserted into a hole site and grouted, when the anchor rod is installed, the length of the anchor rod exposed out of the hole is measured by a steel ruler, the length of the anchor rod in the hole is calculated (the error is controlled within the range of +/-50 mm), and the anchoring length is ensured. Before installation, each steel bar needs to be ensured to be straight, derusted and degreased, and the serial number of the anchor hole is carefully checked again before the anchor rod body is installed;
s8: and (5) checking the pullout resistance of the anchor rod.
In order to ensure that the anchor rod has reliable anchoring force, a strict uplift resistance test is required to be carried out on not less than 3 anchor rods on each slope surface under the field condition, test data must be compared with the original design, and if the test result is greatly different from the original design result, anchor rod anchoring parameters are adjusted by a design party.
After the construction is completed, the supervisor or owner should be accepted by the standards of table 1.
TABLE 1 quality acceptance Standard Table
Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.
Claims (7)
1. A foundation pit supporting construction method is characterized in that: the construction method specifically comprises the following steps:
s1: determining hole sites according to the requirements of a design elevation;
s2: selecting a drilling machine based on the category of the anchoring stratum, the bore diameter of the anchor rod, the depth of the anchor rod and the construction site conditions;
s3: according to the stratum conditions, erecting a scaffold meeting the bearing capacity and the stability conditions of the drilling machine to install the drilling machine;
s4: drilling a bolt hole;
s5: continuing stable drilling for 1-2 minutes, and using high-pressure air to completely remove rock powder and water in the hole out of the hole;
s6: checking whether the anchor rod hole meets the design requirement, if so, performing S7, and if not, performing rectification until the design requirement is met;
s7: installing an anchor rod;
s8: and (5) checking the pullout resistance of the anchor rod.
2. A method of constructing a foundation pit support according to claim 1, wherein: the conditions for installing the drilling machine in the S3 are as follows: ensuring that the longitudinal and transverse errors of the anchor rod hole in position during drilling cannot exceed +/-50 mm; the elevation error is not more than +/-100 mm; the inclination angle and the direction of the drill hole meet the design requirements; the allowable error of the inclination angle is +/-1.0 degree; the orientation tolerance is ± 2.0 °.
3. A method of constructing a foundation pit support according to claim 1, wherein: the drilling requirement of S4 is: and during drilling, a dry drilling mode is adopted, and a water drilling mode is forbidden.
4. A method of retaining and retaining a foundation pit according to claim 3, wherein: the drill bit diameter of the drill bit used for drilling the anchor rod hole of the S4 is not less than the designed anchor rod hole diameter; the actual drilling depth is at least 300mm greater than the design drilling depth.
5. A method of constructing a foundation pit support according to claim 1, wherein: when it is checked that the pressure-bearing water flows out of the anchor rod hole when the anchor rod hole is cleaned in the S5, drainage holes need to be formed around the pressure-bearing water to release the pressure and flow rate of the pressure-bearing water.
6. A method of constructing a foundation pit support according to claim 1, wherein: the conditions for inspecting the qualification of the anchor rod hole in the S6 are as follows: when the drill bit is pushed smoothly, impact or shaking is not generated; the testing and delivering length of the drilling tool meets the designed anchor rod hole depth; the drill is smoothly withdrawn; the phenomena of obvious splashing of dust slag and water are not detected by blowing with high-pressure air.
7. A method of constructing a foundation pit support according to claim 1, wherein: the S7 specifically includes:
s71: manufacturing an anchor rod body by using a phi 32 steel bar;
s72: arranging a group of steel bar positioning frames every 1-3m along the axial direction of the anchor rod body;
s73: carrying out anti-corrosion treatment on the insertion end of the anchor rod body;
s74: and inserting the anchor rod body into the hole position determined by the S1 according to the design requirement and grouting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010484822.7A CN111676980A (en) | 2020-06-01 | 2020-06-01 | Foundation pit supporting construction method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010484822.7A CN111676980A (en) | 2020-06-01 | 2020-06-01 | Foundation pit supporting construction method |
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| Publication Number | Publication Date |
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| CN111676980A true CN111676980A (en) | 2020-09-18 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202010484822.7A Pending CN111676980A (en) | 2020-06-01 | 2020-06-01 | Foundation pit supporting construction method |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102108708A (en) * | 2010-12-16 | 2011-06-29 | 张继红 | Compound anchor rod foundation pit building envelope, construction method thereof and adopted cement soil notcher |
| CN105155535A (en) * | 2015-08-17 | 2015-12-16 | 郑州科技学院 | Construction method for anchor rod for civil engineering |
| CN107514266A (en) * | 2017-09-06 | 2017-12-26 | 海南大学 | Shield export ＆ import bolt anchorage soil body construction method |
| CN108203983A (en) * | 2018-03-02 | 2018-06-26 | 中国五冶集团有限公司 | A kind of deep foundation pit supporting structure and method |
| CN109610470A (en) * | 2018-11-30 | 2019-04-12 | 福建建中建设科技股份有限公司 | A kind of base pit stand construction using three axes agitating pile machine |
| CN110106896A (en) * | 2019-06-03 | 2019-08-09 | 南华大学 | A kind of prefabricated card slot type anchor pier lattice girder construction and assembling constructing method of slope reinforcement |
-
2020
- 2020-06-01 CN CN202010484822.7A patent/CN111676980A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102108708A (en) * | 2010-12-16 | 2011-06-29 | 张继红 | Compound anchor rod foundation pit building envelope, construction method thereof and adopted cement soil notcher |
| CN105155535A (en) * | 2015-08-17 | 2015-12-16 | 郑州科技学院 | Construction method for anchor rod for civil engineering |
| CN107514266A (en) * | 2017-09-06 | 2017-12-26 | 海南大学 | Shield export ＆ import bolt anchorage soil body construction method |
| CN108203983A (en) * | 2018-03-02 | 2018-06-26 | 中国五冶集团有限公司 | A kind of deep foundation pit supporting structure and method |
| CN109610470A (en) * | 2018-11-30 | 2019-04-12 | 福建建中建设科技股份有限公司 | A kind of base pit stand construction using three axes agitating pile machine |
| CN110106896A (en) * | 2019-06-03 | 2019-08-09 | 南华大学 | A kind of prefabricated card slot type anchor pier lattice girder construction and assembling constructing method of slope reinforcement |
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Application publication date: 20200918 |