Summary of the invention
The technical problem that the present invention solves is to provide a kind of foundation ditch construction method, solves existing technical deficiency.
The present invention is from ± 0.00, and from top to bottom, body structure portion carries out construction from bottom to top to basement structure part simultaneously.Basement first carries out the horizontal structure such as beam, the plate construction of each layer, the more interspersed vertical structure such as post, the shear wall construction carrying out each layer.Before vertical load-carrying members all do not complete and reach design strength, above completed permanent load and working load carry by the interim steel-support post arranged and pass to engineering pile.Every root steel-support post all inserts engineering pile 2.5m, and when drill-pouring Construction of Engineering Pile, after the welding of post reinforcing cage, entirety hangs in hole.For ensureing the standard that steel-support post is installed perpendicularity deviation and is less than its length 1/500, steel-support post on-station position arranges fixing steel plate, ensures the horizontal level of steel-support post, with the Plane Angle of axis, capital absolute altitude and verticality.Behind every root steel-support post lifting location, forbid that heavy mechanical equipment is near stake holes and fixing steel plate, must not remove fixing steel plate in the 48h after pile concrete has watered.Diaphragm wall is that bracing of foundation pit wall is held concurrently as outer wall of basement.
Construction of diaphragm wall adopts fluid pressure type grab chute forming technique, carries out excavation and the concreting of unit groove section with " jumping hole method ".Grooving vertical precision is not more than 1/300.The bad settling amount that can increase diaphragm wall of diaphragm wall sediment process, construction method not only adopt reverse circular technique carry out scarfing cinder, after also adopting into wall, high-pressure injected water method for slurry is reinforced, in every width diaphragm wall reinforcing cage, all pre-buried 2 compaction grouting pipes, carry out grouting and reinforcing to 2m depth bounds at the bottom of diaphragm wall.In addition, spray the little stabilizing solution of proportion by powerful jet pump to bottom land, the sediment at the bottom of hole from a side blow to opposite side, open another suction pump simultaneously, by suction pipe sediment larger for proportion from opposite side sucking-off, thus sediment at the bottom of hole is effectively controlled.
Prevent from concrete from streaming being the difficult point in construction of diaphragm wall process.The present invention adopts special joint case and locking notch pipe, is filled in and adjacent slot width joint.Joint case hangs bottom land, and bottom embedded depth is not less than 50cm.After locking notch pipe is in place, fits well from joint case and locking notch pipe for preventing concrete and stream, closely knit in the earthen backfill of locking notch pipe behind, efficiently avoid because cell wall landslide, concrete stream the dyskinetic construction accident caused to adjacent slot width.Time that pulls of joint case and locking notch pipe considers according to the resistance of concrete strength grade, initial setting time, final setting time, temperature and diaphragm wall, joint case and locking notch pipe is loosened among a small circle after concrete casting 2h, after this loosen once every 15min, to final set, slowly pull up joint case and locking notch pipe.
The speed of pit earthwork excavation progress is the key of restriction basement and whole engineering construction progress.In order to solve the lateral deformation of speed and the reduction diaphragm wall accelerating to cut the earth and ensure the contradiction of workmanship and construction safety, after taking first open cut, tunneling and machinery are cut the earth, concrete steps are as follows: outside the first floor earthwork is wide along diaphragm wall 10m, adopt benzvalene form open cut, dig and cause below underground 1 floor layer; After ± 0.00 floor and underground 1 floor layer have been constructed, then carry out the tunneling of 2, the 3 layers of earthwork in underground; Tunneling soil adopts excavator, utilizes miniature diesel tipping lorry to complete earthwork horizontal transport in foundation ditch, is grabbed bucket and assist small-sized claw bucket sling to be unearthed from floor reserved opening, complete a cubic metre of earth vertical transport by machinery.
Traditional handicraft adopts fetal membrane of laying bricks, concreting bed course makes basement floor, speed of application is slow, concrete surface planeness and presentation quality are also poor, the present invention is by 0.7m below excavation of earthwork to floor soffit, set up framed bent and install template, to accelerate basement construction progress, ensure that the quality of concrete surface.
Excessive in order to prevent diaphragm wall lateral displacement to be out of shape, produce seepage even structural deterioration, every layer is carried out blockette construction along diaphragm wall, the length of every block block is 15 ~ 20m, width is 10 ~ 14m, and accelerate the excavation of each block earthwork and the construction of floor as far as possible, to shorten the Deformation of Diaphragm Wall time, reduce shift value.
The present invention is the construction first carrying out the horizontal structures such as basement floor base plate, more successively the interspersed vertical structure such as post, shear wall that carries out is constructed.Therefore concrete column joint seam is more, and muscle quality of connection as main in post is unreliable, and casting and compacting of concrete leakiness will directly affect the safety of structure.The main muscle of post connect specific practice adopt as follows: first by be connected end reinforced cut flat, the method of cutting is adopted to peel a part off in end reinforced vertical rib to be connected and cross rib screw-rolling machine, then directly rolling goes out silking, couples together with special silking connector, forms the connection of reinforcing bar.Traditional concrete column muscle connects for overlap joint electric welding, and compared with conventional art, its advantage has: 1. strength of joint is high, and energy 100% plays reinforced steel bar strength; 2. silking connector is short, and silking button number is few, does not need torque spanner, easy to operate, and connection speed is fast; 3. material-saving, energy-conservation, economic, saves steel more than 35% than other mechanical connection manner.
If post concrete joint position adopts grouting material mode to connect, complex operation is time-consuming, directly affects the construction speed of superstructure.The present invention takes to connect special bell mouth on column template top, and concrete is once poured onto top, and post four sides arranges punching block extension vibration board and vibrates, and ensure that concrete compactness.
Joint between diaphragm wall two width should reach and bear bending resistance, shearing resistance requirement, should not make it the weak link becoming strength and stiffness; In addition often produce percolating water, therefore traditional underground continuous wall connector is improved.
Diaphragm wall overlapping part water proof structure of the present invention comprises diaphragm wall, anchor rib, steel seal ring, steel plate, expansive concrete, high-strength epoxy resin, anchor rib buried underground by diaphragm wall, anchor rib is 7 fonts, to strengthen anchorage length, anchor rib diameter is 22 ~ 25mm, anchor rib weldable steel seal ring, steel seal ring thickness is 3 ~ 4mm, the width of steel seal ring is 35 ~ 45mm, and steel seal ring has blocked the infiltration path of anchor rib, avoids anchor rib to there is infiltration hidden danger.Outside diaphragm wall, steel plate is set, steel plate thickness is 10 ~ 12mm, steel plate arranges preformed hole, preformed hole diameter is 25 ~ 28mm, and anchor rib is through steel plate preformed hole, and the space filling high-strength epoxy resin between anchor rib and preformed hole is closed, between the steel plate of adjacent diaphragm wall, space is 15 ~ 20mm, build expansive concrete in space, expansive concrete intensity be C35 or more than, expansive concrete effectively can prevent building rear concrete and occur shrinkage crack.
The smooth main path in underground continuous wall face is kept to be control to reduce cell wall landslide in work progress by mud, therefore, before grooving by the sewage in guide groove and dirt removal clean, different soil layers is taked to the proportioning of different slurry coat methods, specific as follows: for clay, the weight proportion of slurry coat method is: water is 100%, and swell soil is 8%, and soda ash is 0.12% ~ 0.15%, sodium carboxymethylcellulose is 0.06% ~ 0.08%; For silty clay, the proportioning of slurry coat method is: water is 100%, and swell soil is 9%, and soda ash is 0.16% ~ 0.19%, sodium carboxymethylcellulose is 0.09% ~ 0.11%; For silt, the proportioning of slurry coat method is: water is 100%, and swell soil is 10%, and soda ash is 0.20% ~ 0.23%, sodium carboxymethylcellulose is 0.12% ~ 0.14%; For sand, the proportioning of slurry coat method is: water is 100%, and swell soil is 8% ~ 12%, and soda ash is 0.24% ~ 0.27%, sodium carboxymethylcellulose is 0.15% ~ 0.17%.
Diaphragm wall of the present invention is bracing of foundation pit wall, and be again outer wall of basement, damp proof insulation barrier performance is poor, needs to arrange bricking wall apart from basement inwall 30cm position inside diaphragm wall.Between in making to be formed between diaphragm wall inwall and brick clamp wall, play water conservancy diversion and moistureproof effect.
The conventional method that diaphragm wall is connected with basement bottom board, floor flexibly connects method, namely at basement floor absolute altitude place, cut by diaphragm wall reinforcement cover; expose main muscle; build together with basement floor again, only transmit horizontal force between the two, do not transmit vertical force and moment of flexure.The present invention adopts rigid connecting connection, namely on the arrangement of reinforcement absolute altitude of basement bottom board and floor, reinforcing bar connector is buried underground at the interior wall of diaphragm wall in advance, after basement excavation when construction base plate and floor, its base plate and floor bar by reinforcing bar connector directly and diaphragm wall be linked to be entirety, become rigid joint, through the underground structure of rigid joint process, the performance in anti-settling, resist displacement etc. all can be improved.Compared with traditional method, the present invention obviously has greatly improved in mechanical property.
For conscientiously improving the effect of temporary support, all temporary support all need when constructing prestressing force of constructing.1. in the installation process such as column braces, horizontal support, increase by 2 steel plates at steel tube end part and strengthen bearing, after steel pipe is in place, adopt hydraulic jack to exert pressure, to steel pipe construction Prestressing; 2. concrete temporary support all mixes TEA micro-expanding agent, to reduce or to avoid shrinking.
Work efficiency of the present invention is high, the duration is short, reliable in quality, high financial profit, has following characteristics:
(1) place of engineering geology and hydrogeology complexity is applicable to.
(2) place that construction plant is narrow and small is applicable to.The construction plant of some engineerings is very narrow, and according to traditional space enclosing structure, piles in row adds cement mixing pile sealing, and considers the scope of operation between enclosure wall and outer wall of basement, then will greatly reduce building usable floor area.And present invention employs the technical scheme of enclosure wall and outer wall of basement unification, then greatly can improve the land utilization ratio in red line.
(3) be applicable to surrounding environment complexity and high area is required to security reliability.Under house owed by a citizen around some engineerings and road, pipe network facilities is intensive, is embedded with responsive gas flue under road, requires very high to the security reliability of bracing of foundation pit.In the present invention, diaphragm wall adds inner support, forms effective retaining design, and rigidity is large, and displacement is little with distortion.
(4) engineering of construction period anxiety is applicable to.The construction period of diaphragm wall adds cement mixing pile than conventional bored pile or rotary churning pile wants much shorter, can shortening for 1/3 ~ 1/2 duration, creating condition for effectively controlling total lever factor.
(5) engineering that the excavation of foundation pit degree of depth is large is applicable to.The excavation of foundation pit degree of depth is larger, and the water and soil lateral pressure suffered by enclosure wall is also larger, more easily produces Seepage, and requires higher to the strength and stiffness of going along with sb. to guard him piling wall adopted, also stricter to the stability requirement of retaining design.And diaphragm wall, in conjunction with inner support, has exactly possessed the advantage of these several respects in the present invention, namely in, stability large at anti-leakage, intensity and toughness and globality, there is unrivaled superiority.
(6) analyze from bracing engineering cost, the technical program adopts enclosure wall and outer wall of basement unification, more cost-saving than conventional method.
Detailed description of the invention
Describe the present invention below in conjunction with accompanying drawing.
The present embodiment is from ± 0.00, and from top to bottom, body structure portion carries out construction from bottom to top to basement structure part simultaneously.Basement first carries out the horizontal structure such as beam, the plate construction of each layer, the more interspersed vertical structure such as post, the shear wall construction carrying out each layer.Before vertical load-carrying members all do not complete and reach design strength, above completed permanent load and working load carry by the interim steel-support post arranged and pass to engineering pile.Every root steel-support post all inserts engineering pile 2.5m, and when drill-pouring Construction of Engineering Pile, after the welding of post reinforcing cage, entirety hangs in hole.For ensureing the standard that steel-support post is installed perpendicularity deviation and is less than its length 1/500, steel-support post on-station position arranges fixing steel plate, ensures the horizontal level of steel-support post, with the Plane Angle of axis, capital absolute altitude and verticality.Behind every root steel-support post lifting location, forbid that heavy mechanical equipment is near stake holes and fixing steel plate, must not remove fixing steel plate in the 48h after pile concrete has watered.Diaphragm wall 1 is that bracing of foundation pit wall is held concurrently as outer wall of basement.
Diaphragm wall 1 is constructed and is adopted fluid pressure type grab chute forming technique, carries out excavation and the concreting of unit groove section with " jumping hole method ".Grooving vertical precision is not more than 1/300.Construction method not only adopt reverse circular technique carry out scarfing cinder, after also adopting into wall, high-pressure injected water method for slurry is reinforced, in every width diaphragm wall 1 reinforcing cage, all pre-buried 2 compaction grouting pipes, carry out grouting and reinforcing to diaphragm wall 1 end 2m depth bounds.In addition, spray the little stabilizing solution of proportion by powerful jet pump to bottom land, the sediment at the bottom of hole from a side blow to opposite side, open another suction pump simultaneously, by suction pipe sediment larger for proportion from opposite side sucking-off, thus sediment at the bottom of hole is effectively controlled.
The present embodiment adopts special joint case and locking notch pipe, is filled in adjacent slot width joint.Joint case hangs bottom land, and bottom embedded depth is not less than 50cm.After locking notch pipe is in place, fits well from joint case and locking notch pipe for preventing concrete and stream, closely knit in the earthen backfill of locking notch pipe behind.Time that pulls of joint case and locking notch pipe considers according to the resistance of concrete strength grade, initial setting time, final setting time, temperature and diaphragm wall 1, joint case and locking notch pipe is loosened among a small circle after concrete casting 2h, after this loosen once every 15min, to final set, slowly pull up joint case and locking notch pipe.
After pit earthwork excavation takes first open cut, tunneling and machinery are cut the earth, and concrete steps are as follows: outside the first floor earthwork is wide along diaphragm wall 10m, adopt benzvalene form open cut, dig and cause below underground 1 floor layer; After ± 0.00 floor and underground 1 floor layer have been constructed, then carry out the tunneling of 2, the 3 layers of earthwork in underground; Tunneling soil adopts excavator, utilizes miniature diesel tipping lorry to complete earthwork horizontal transport in foundation ditch, is grabbed bucket and assist small-sized claw bucket sling to be unearthed from floor reserved opening, complete a cubic metre of earth vertical transport by machinery.
The present embodiment, by 0.7m below excavation of earthwork to floor soffit, is set up framed bent and is installed template, to accelerate basement construction progress, ensure that the quality of concrete surface.
Excessive in order to prevent diaphragm wall 1 lateral displacement to be out of shape, produce seepage even structural deterioration, every layer is carried out blockette construction along diaphragm wall 1, the length of every block block is 15 ~ 20m, width is 10 ~ 14m, and accelerate the excavation of each block earthwork and the construction of floor as far as possible, to shorten diaphragm wall 1 deformation time, reduce shift value.
The main muscle of post connect specific practice adopt as follows: first by be connected end reinforced cut flat, the method of cutting is adopted to peel a part off in end reinforced vertical rib to be connected and cross rib screw-rolling machine, then directly rolling goes out silking, couples together with special silking connector, forms the connection of reinforcing bar.
If post concrete joint position adopts grouting material mode to connect, complex operation is time-consuming, directly affects the construction speed of superstructure.The present embodiment is taked to connect special bell mouth on column template top, and concrete is once poured onto top, and post four sides arranges punching block extension vibration board and vibrates, and ensure that concrete compactness.
Fig. 1 is diaphragm wall overlapping part water proof structure schematic diagram.The present embodiment diaphragm wall overlapping part water proof structure comprises diaphragm wall 1, anchor rib 2, steel seal ring 3, steel plate 4, expansive concrete 5, high-strength epoxy resin 6, anchor rib 2 buried underground by diaphragm wall 1, anchor rib 2 is 7 fonts, anchor rib 2 diameter is 22mm, anchor rib 2 weldable steel seal ring 3, steel seal ring 3 thickness is 3mm, the width of steel seal ring 3 is 35 ~ 45mm, steel plate 4 is set outside diaphragm wall 1, steel plate 4 thickness is 10mm, steel plate 4 arranges preformed hole, preformed hole diameter is 25mm, anchor rib 2 is through steel plate 4 preformed hole, space filling high-strength epoxy resin 6 between anchor rib 2 and preformed hole is closed, between the steel plate of adjacent diaphragm wall, space is 15 ~ 20mm, expansive concrete is built in space, expansive concrete intensity be C35 or more than, expansive concrete effectively can prevent building rear concrete and occur shrinkage crack.
When diaphragm wall 1 is constructed, different soil layers is taked to the proportioning of different slurry coat methods, specific as follows: for clay, the weight proportion of slurry coat method is: water is 100%, and swell soil is 8%, and soda ash is 0.12% ~ 0.15%, sodium carboxymethylcellulose is 0.06% ~ 0.08%; For silty clay, the proportioning of slurry coat method is: water is 100%, and swell soil is 9%, and soda ash is 0.16% ~ 0.19%, sodium carboxymethylcellulose is 0.09% ~ 0.11%; For silt, the proportioning of slurry coat method is: water is 100%, and swell soil is 10%, and soda ash is 0.20% ~ 0.23%, sodium carboxymethylcellulose is 0.12% ~ 0.14%; For sand, the proportioning of slurry coat method is: water is 100%, and swell soil is 8% ~ 12%, and soda ash is 0.24% ~ 0.27%, sodium carboxymethylcellulose is 0.15% ~ 0.17%.
The present embodiment diaphragm wall 1 is bracing of foundation pit wall, and be again outer wall of basement, damp proof insulation barrier performance is poor, needs to arrange bricking wall apart from basement inwall 30cm position inside diaphragm wall 1.
Diaphragm wall 1 is connected with basement bottom board, floor and adopts rigid connecting connection, namely on the arrangement of reinforcement absolute altitude of basement bottom board and floor, reinforcing bar connector is buried underground at the interior wall of diaphragm wall 1 in advance, after basement excavation when construction base plate and floor, its base plate and floor bar by reinforcing bar connector directly and diaphragm wall 1 be linked to be entirety and become rigid joint.
All temporary support all need when constructing prestressing force of constructing.1. in the installation process such as column braces, horizontal support, increase by 2 steel plates at steel tube end part and strengthen bearing, after steel pipe is in place, adopt hydraulic jack to exert pressure, to steel pipe construction Prestressing; 2. concrete temporary support all mixes TEA micro-expanding agent, to reduce or to avoid shrinking.