CN106436720A - Small-size deep foundation pit supporting structure for pipe jacking construction - Google Patents

Abstract

The invention discloses a small-size deep foundation pit supporting structure for pipe jacking construction. The supporting structure is constructed through the steps that firstly, bored perfusion pile rows are constructed around the determined foundation pit position, a high-pressure jet grouting pile row is constructed in a gap formed between every two adjacent bored perfusion pile rows, a side slope is excavated from the ground, an annular crown beam is poured on the tops of the bored perfusion pile rows, asphalt felt is laid between the crown beam and pile bodies, and then a brick wall is built on the top of the crown beam; secondly, a foundation pit is excavated after the crown beam reaches the required strength, and after the foundation building surface meets the construction requirement, the side wall of the foundation pit and an inner lining (the position where a jacking pipe is arranged in a penetrating mode is reserved) of a bottom plate are poured with reinforced concrete; lastly, opening treatment is conducted on the jacking pipe, a second-stage reinforced concrete layer is built on the dismantling face, and after the later-period pipe jacking construction requirements are met, overall supporting structure construction is completed. According to the small-size deep foundation pit supporting structure for pipe jacking construction, a conventional cantilever pile supporting method is broken through, and the supporting structure arranged in the foundation pit in a finite space meets the supporting requirement of a surrounding complex environment; meanwhile, by combining the construction characteristics of pipe jacking construction, basic guarantee conditions are provided for normal and safe construction of pipe jacking engineering.

Description

Jacking construction small size deep foundation pit supporting structure

Technical field

The present invention relates to piping laying construction technology, especially relate to a kind of jacking construction small size deep foundation pit support knot Structure.

Background technology

Jacking construction is exactly no-dig technique（Or excavate less）Pipeline（Including Urban Underground water supply and sewerage pipeline, sky hot gas petroleum pipeline Road, communication cable pipeline etc.）Burial and construction technology.This technology thoroughly solves in piping laying work progress to City Building Destruction and the difficult problem such as impact to road traffic, steady soil and environmental protection aspect advantage are become apparent from.Normal condition Under, for the various pipe traverse project for 1m ~ 3m for the caliber, particularly in urban environment and in order to protect earth's surface important Ecology, greenery patches and the facility such as river course, building exempt from and destroy it will usually select the jacking construction of non-excavation type.

For meeting long-distance pipe jacking engine request, need to arrange various working pits or received well base at engineering two ends and along journey Hole, is less than the foundation ditch of 8m, typically carries out supporting using conventional single-cantilever stake for depth.But some push pipe foundation ditches are for warp Ji, investment reduction, interior diameter is generally less（It is only capable of meeting jacking construction requirement）, therefore conventional cantilever soldier pile retaining structure scheme is subject to To restriction, and subsurface geology complicated condition, the foundation ditch in urban environment, if peripheral facility（Various pipelines, optical cable and building Thing）Numerous, it is also not suitable for the supporting scheme using conventional anchor cable and inner support combine and is constructed, therefore, for this little Diameter（3 ~ 8 meters）And depth is more than 8m（8 ~ 13 meters）Deep basal pit be accomplished by designing a kind of new supporting scheme, to meet safety The requirement of construction.

Content of the invention

It is an object of the invention to provide one kind can meet pipe-jacking project construction safety, protect surrounding enviroment to pacify again Entirely, and jacking construction small size deep foundation pit supporting structure economic and that social benefit is all good.

For achieving the above object, the present invention can take following technical proposals：

Jacking construction of the present invention small size deep foundation pit supporting structure, its construction procedure is：

The first step, around the multiple cast-in-situ bored piles of foundation ditch interval construction around the foundation ditch position that ground determines, forms annular Drill-pouring row of piles；The diameter of cast-in-situ bored pile, depth can be according to hydrogeologic condition, peripheral facility load, pattern foundation pit supporting structure peaces The conditions such as the foundation depth of congruent level and supporting calculate and determine；

Second step, according to the actual underground water elevation measured, high-pressure rotary jet grouting pile of constructing at the gap of adjacent two cast-in-situ bored piles, High-pressure rotary jet grouting pile 2 is made to form the water-stop curtain of closing together with cast-in-situ bored pile 1, the pile body diameter of wherein high-pressure rotary jet grouting pile is less than The pile body diameter of cast-in-situ bored pile；

3rd step, from ground according to not suddenly in 1:1 side slope is excavated, and cutting depth is not more than three meters, reduces slope pair as far as possible The impact of surrounding enviroment, then pours annular Guan Liang, the combination of annular Guan Liang and cast-in-situ bored pile at drill-pouring row of piles top Laying asphalt felt on face is it is ensured that stake top forms freely-supported force structure；Then build height by laying bricks or stones in circular crown back portion and be less than two meters Brick wall；

4th step, after annular Guan Liang reaches intensity requirement, by projected depth excavation pit；

5th step, after excavation of foundation pit finishes and foundation plane reaches construction requirement, carries out the cast of foundation ditch liner：Poured into a mould with reinforced concrete Push pipe is worn position during the wall of casting lining side and reserves out by liner side wall and interior underboarding；

6th step, after the intensity of detection cast-in-situ bored pile, high-pressure rotary jet grouting pile and liner side wall, interior underboarding reaches acceptance condition, Carry out broken pile enabling at push pipe to process：According to design requirement, by the cast-in-situ bored pile at reserved position of pushing tube and high-pressure rotary jet grouting pile Pile body remove, and build reinforced concrete floor by laying bricks or stones in dismounting face, to meet the space requirement of later stage jacking construction, integer support is tied Structure construction completes.

It is an advantage of the current invention that breaching the method for protecting support of conventional cantilever stake, and unlike conventional cantilever stake, top Guan Liang is not to arrange for detailing requiments, but and campshed is together as overall force structure composition support system, this prop System can meet the supporting of around environment in the foundation ditch of the confined space, in combination with the construction characteristic of pipe-jacking project, Provide the foundation guaranteed conditions for the construction of pipe-jacking project normal safe.

Brief description

Fig. 1 is the supporting construction top view that present invention construction finishes.

Fig. 2 is Figure 1A-A to sectional view.

Fig. 3 is the sectional schematic diagram at Fig. 1 poling.

Specific embodiment

Jacking construction of the present invention small size deep foundation pit supporting structure as shown in Figure 1-2, according to walking in detail below Suddenly constructed：

The first step, around the multiple cast-in-situ bored piles 1 of foundation ditch interval construction around the foundation ditch position that ground determines, forms annular Drill-pouring row of piles；During Specific construction, the depth of the diameter of cast-in-situ bored pile and interval and supporting is according to foundation depth, present situation Geological conditions, all side load and Groundwater feature etc. carry out calculating comprehensive determination.Under normal circumstances, cast-in-situ bored pile is straight Footpath is typically just intended to be 0.80m～2m；

Second step, according to the actual underground water elevation measured, high-pressure rotary jet grouting pile of constructing at the gap of adjacent two cast-in-situ bored piles 1 2, the wherein pile body diameter of high-pressure rotary jet grouting pile 2 is less than the pile body diameter of cast-in-situ bored pile 1 it is contemplated that base pit engineering feature and economy Save, the pile body diameter of high-pressure rotary jet grouting pile 2 is generally 40 ~ 80cm, and high-pressure rotary jet grouting pile 2 and cast-in-situ bored pile 1 cooperatively form The water stop curtain structure of closing, meets the internal anhydrous job requirements of construction period foundation ditch；

3rd step, from ground 1:After 1 slope excavates three meters, pouring longitudinal section at drill-pouring row of piles top is rectangle or pros The annular Guan Liang 3 of shape, laying asphalt felt 4 on the faying face of annular Guan Liang 3 and cast-in-situ bored pile 1 is it is ensured that stake top formation freely-supported is subject to Power structure；Then build, at annular Guan Liang 3 top, the brick wall 5 that height is less than two meters by laying bricks or stones, brick wall thickness according to gear soil height can be 24cm or 37cm, facilitates later stage temporary project to remove and surface management work；

4th step, after annular Guan Liang 3 reaches intensity requirement, by projected depth excavation pit 6, the diameter of foundation ditch 6 does not typically surpass Cross eight meters；

5th step, foundation ditch 6 excavates and finishes and after foundation plane reaches construction requirement, carries out the cast of foundation ditch liner：Poured with reinforced concrete The position that wears of push pipe 9 is reserved out during the wall 7 of casting lining side by note liner side wall 7 and interior underboarding 8；Pour thickness according to Construction technology and push pipe integrally push up power and calculate requirement, generally 20 ~ 40cm；

6th step, the intensity of detection cast-in-situ bored pile 1, high-pressure rotary jet grouting pile 2 and liner side wall 7, interior underboarding 8 reaches acceptance condition Afterwards, carry out broken pile enabling at push pipe to process：According to design requirement, by the cast-in-situ bored pile at reserved position of pushing tube and high-pressure rotary-spray The pile body of stake is removed, and builds the second stage of reinforced concrete floor 10 by laying bricks or stones in dismounting face（Borehole structure, according to pipe diameter and combine push pipe Technological requirement, is computed determining, generally 30 ~ 50cm）, by the Bar Anchorage at pile body broken pile in reinforced concrete floor, with Meet the space requirement of later stage jacking construction, so far, integer support structure construction completes.

7th step, after integer support structure reaches intensity requirement, carries out jacking and two end pipes of push pipe 9 according to a conventional method The connection in road, the section structure of the push pipe 9 passing from the second stage of reinforced concrete floor 10 is as shown in Figure 3；Can also carry out permanent Combine with temporary project, pour pipeline valve pit and pipe laying valve member at this foundation ditch position, or on demand at pipeline Corner arranges anchor block 11, meets the pressure requirements of pipeline.

8th step, when in push pipe 9 and well valve pit or anchor block 11 construction after the completion of, foundation ditch 6 is backfilled, backfill is organic Matter content must not exceed 5%, and compactness cannot be less than 0.96, and needs compaction in layers to process.

According to structural mechanics method, supporting construction of the present invention is carried out checking correlation computations：1. by the top pile body after removing Deadweight overhangs at Guan Liang as Vertical Load, and at this, Guan Liang is checked according to simply supported beam, and support distance is that both sides are complete At pile body position.2. by whole for top pile body Gravitative Loads in the Dong Dingchu of the second stage of lining concrete, the second stage of lining cutting circular hole according to " O " type framework carries out structure and checks.3. according to two ends freely-supported, bearing is respectively Guan Liang and inner liner location to the top pile body after broken pile Place, pile body is primarily subjected to horizontal earth pressure and is checked.4. utilize the reaction force to liner for the top pile body, check liner plane Framework.

According to member structure system, calculated according to structural mechanics method, computation model is as follows：Stake top Guan Liang is according to list Support structure designs, Guan Liang cross section is rectangle, reinforced concrete structure：1. horizontal direction：Supporting construction top Guan Liang according to Structural mechanics method calculates, and top Guan Liang is born horizontal loading and calculated according to hinged-support transmission counter-force, according to reinforced concrete Native flexure member correlation formula is determined Guan Liang section.2. vertical direction：Pile body pair when considering that push pipe opens the door The impact of Guan Liang vertical load is checked, and carries out internal force meter according to armored concrete flexure member correlation formula Calculate.

Conclusion：Supporting construction of the present invention is carried out after checking calculation according to said method it was demonstrated that：On small size deep basal pit top In plumber's journey, by using Guan Liang, as a structure stress system part, and the common coordinative role of campshed, as a kind of pipe-jacking project Foundation pit supporting construction can fully meet jacking construction safety requirements.

Claims (1)

1. a kind of jacking construction with small size deep foundation pit supporting structure it is characterised in that：Including following construction procedures：

The first step, around the multiple cast-in-situ bored piles of foundation ditch interval construction around the foundation ditch position that ground determines, forms annular Drill-pouring row of piles；

Second step, according to the actual underground water elevation measured, high-pressure rotary jet grouting pile of constructing at the gap of adjacent two cast-in-situ bored piles, High-pressure rotary jet grouting pile 2 and cast-in-situ bored pile 1 is made to form the water-stop curtain of closing, the wherein pile body diameter of high-pressure rotary jet grouting pile is less than boring The pile body diameter of bored concrete pile；

3rd step, from ground according to not suddenly in 1:1 side slope is excavated, and cutting depth is not more than three meters, then in drill-pouring Row of piles top pours annular Guan Liang, and on the faying face of annular Guan Liang and cast-in-situ bored pile, laying asphalt felt is it is ensured that stake top forms letter Prop up force structure；Then build, in circular crown back portion, the brick wall that height is less than two meters by laying bricks or stones；

4th step, after annular Guan Liang reaches intensity requirement, by projected depth excavation pit；

5th step, after excavation of foundation pit finishes and foundation plane reaches construction requirement, carries out the cast of foundation ditch liner：Poured into a mould with reinforced concrete Push pipe is worn position during the wall of casting lining side and reserves out by liner side wall and interior underboarding；

6th step, after the intensity of detection cast-in-situ bored pile, high-pressure rotary jet grouting pile and liner side wall, interior underboarding reaches acceptance condition, Carry out broken pile enabling at push pipe to process：According to design requirement, by the cast-in-situ bored pile at reserved position of pushing tube and high-pressure rotary jet grouting pile Pile body remove, and build reinforced concrete floor by laying bricks or stones in dismounting face, to meet the space requirement of later stage jacking construction, integer support is tied Structure construction completes.