CN106381866A

CN106381866A - Construction method of ultra-deep underground diaphragm wall in water-rich soft-soil area

Info

Publication number: CN106381866A
Application number: CN201610796528.3A
Authority: CN
Inventors: 古存军; 覃君; 赵伟
Original assignee: China Railway No 2 Engineering Group Co Ltd
Current assignee: China Railway No 2 Engineering Group Co Ltd; China Railway Erju 6th Engineering Co Ltd
Priority date: 2016-08-31
Filing date: 2016-08-31
Publication date: 2017-02-08

Abstract

The invention relates to the technical field of civil engineering construction, in particular to a construction method of an ultra-deep underground diaphragm wall in a water-rich soft-soil area. The construction method comprises the following steps: making an analysis and research on the stability of trench walls of the underground diaphragm wall and doing relevant preparations, preparing wall protecting slurry, building a guide wall, performing trenching construction, wall cleaning and sediment removal, manufacturing and hoisting reinforcing cages, backfilling joints between trench sections, and pouring wall concrete. According to the construction method, through a stability analysis method that introduces strength reduction, the security coefficients of stability of the trench walls are calculated based on a finite difference method; through parameter-reduction circular calculations, not only the limit stress and large deformation state of the trench walls but also the stability coefficients of the trench walls are obtained, which has practice guiding significance in construction; and the results are simple and practical and conform to the habits in the engineering field, and the stability requirements of the trench walls are effectively guaranteed, so that the engineering construction can be completed safely and fast with high quality.

Description

A kind of rich water soft clay area ultra-deep underground continuous wall construction method

Technical field

The present invention relates to engineering construction technology field, particularly to a kind of rich water soft clay area ultra-deep underground continuous wall Construction method.

Background technology

Diaphram wall is that foundation engineering adopts a kind of trench machine, on the ground along the periphery axle of deep excavation project Line, under the conditions of mud off, excavates out a long and narrow deep trouth, after clear groove, hangs steel reinforcement cage in groove, then use tremie method Underwater concreting with tremie method builds up a unit groove section, so carries out paragraph by paragraph, builds up continuous reinforced concrete wall together in underground Wall, as intercepting water, antiseepage, load-bearing, water-retaining structure.After excavating deep trouth, the soil body outside cell wall has to the stability of cell wall , there is slip and the danger caved in considerable influence, in slip or when caving in, a certain plane of disruption in the soil body is carried out the soil body, should The plane of disruption is also sliding surface.

Generally by cutting depth, the earth excavation of the foundation ditch (groove) more than 5m (containing 5m), supporting, dewatering project are referred to as deep base Hole engineering, though simultaneously by cutting depth not less than 5m, geological conditions, surrounding and underground utilities are complicated, or impact is adjoined The earth excavation of foundation ditch (groove) of building (constructing) thing safety, supporting, dewatering project are also referred to as deep-foundation pit engineering, base pit engineering master Including foundation pit supporting system design and construction and earth excavation, it is a comprehensive very strong system engineering, carries in presents The depth definition of the ultra-deep underground continuous wall construction reference deep-foundation pit engineering arriving, that is, refer to the underground that cutting depth is more than 5m (containing 5m) Construction of diaphragm wall, though also refer to cutting depth not less than 5m, the geological conditions in construction of diaphragm wall location, surrounding and ground simultaneously Underground pipelines are complicated, or the construction of diaphragm wall of impact adjacent building (constructing) thing safety.

During carrying out construction of diaphragm wall, due to the physico-mechanical properties of place soil layer, level of ground water, mud matter Amount and the impact of the many factors such as unit groove segment length, it is difficult to ensure that safety, high-quality, quickly completing engineering construction, are related to Subject matter has：

1st, due to the impact of the factor such as creep of stratum soil pressure, pore water pressure, level of ground water and the soil body, in grooving In journey or before body of wall pours, among cell wall plays pendulum, slip or the danger caved in occur at any time；

2nd, a large amount of mud can be used in work progress, mud will be contacted with foundation soil, subsoil water in use, And form mud skin in flute wall surfaces, consume the compositions such as bentonite in mud, soda and CMC, mud can lose part retaining wall Performance；

3rd, sediment thickness has considerable influence to construction quality, and traditional construction method is more difficult to put in place deposit control, leads to Bottom land void slag is blocked up, and the excavation of foundation pit stage may lead to cheat inside and outside artesian water from the supply of diaphragm wall bottom, leads to foundation ditch artesian head It is difficult to reduce, dash forward and the security incident such as gush in hole bottom；

4th, during lifting, safety problem is difficult to solve the steel reinforcement cage used in constructing.

Content of the invention

It is an object of the invention to：Overcome in the presence of prior art during grooving or before body of wall pours, groove Wall plays pendulum and causes the problem that slip or cave in danger occur at any time, provides a kind of rich water soft clay area ultra-deep ground Lower continuous wall construction method, the method is passed through to introduce the method for analyzing stability of strength degradation, on the basis of finite difference calculus It is calculated the safety coefficient of slurry trench stability, by material parameters modification cycle calculations, the limit stress of cell wall not only can be obtained And deformation state, and the coefficient of stability of cell wall will be obtained, there is to construction practical advice meaning, its result simple and practical and Meeting the custom of engineering circles, effectively guaranteeing that slurry trench stability requires, thus safety, high-quality, quickly completing engineering construction.

In order to realize foregoing invention purpose, the invention provides technical scheme below：

A kind of rich water soft clay area ultra-deep underground continuous wall construction method, including following multiple steps：

A, preparation of construction, including assembling groover, setting mud system and surveying and locating, also include to underground continuous wall groove Wall stability is analyzed studying；

B, preparation slurry coat method, make and lead wall, and carry out trenching construction using the slurry coat method having configured；

After c, grooving are up-to-standard, carry out brush wall scarfing cinder；

D, make and lift steel reinforcement cage；

Joint between e, backfill grooving pit section, and place concrete conduit；

F, the Commercial Concrete pouring body of wall concrete of use supply；

Mud in groove in g, recycling step c and f, and carry out deteriorating mud conditioning；

When carrying out Stability Analysis of Trenches of Diaphragm Wall, comprise the following steps：

A1, according to soil mechanics planing theory, take the slip wedge soil body outside diaphragm wall cell wall to be analyzed, obtain cell wall The safety coefficient of stability, the described slip wedge shape soil body is the soil body that diaphragm wall cell wall, soil mass sliding surface and cell wall depth form；

A2, the intensity index parameter of the adjustment soil body, including cohesion c and angle of friction φ, obtain safety coefficient F_s；

A3, set up diaphragm wall excavate plane strain model, analyze the impact to slurry trench stability for the artesian water；

A4, selection mud parameter, improve the safety coefficient of slurry trench stability, so that slurry trench stability sexual satisfaction is required.

From the point of view of continuous wall trench underground process, compacted due to stratum soil pressure, pore water pressure, level of ground water and the soil body The impact of factor such as become, during grooving or before body of wall pours, among cell wall plays pendulum, cunning occurs at any time The danger split or cave in.Therefore, in construction, should in advance and must according to the physico-mechanical properties of place soil layer, level of ground water, The factor such as quality of mud fluid and unit groove segment length, carries out stability analyses to cell wall, and takes corresponding retaining wall measure it is ensured that cell wall Stablize.By the way, introduce the concept of strength degradation, be calculated slurry trench stability on the basis of finite difference calculus Safety coefficient, by material parameters modification cycle calculations, limit stress and the large deformation state of cell wall not only can be obtained, and will Obtain the coefficient of stability of cell wall, there is to construction practical advice meaning, its result is simple and practical and custom that meet engineering circles, Effectively guarantee that slurry trench stability requires.

Preferably, in step a4, described mud parameter includes mud liquid level, volume weight of slurry, mud viscosity and mud Slurry sand factor.

Preferably, in described step b, prepare slurry coat method and comprise the following steps：

B1, arrangement mud plant, enable pit capacity to meet slurry consumption during trenching construction；

B2, configuration plant, including the mud pit configuring as transfer and slurry tank；

B3, get out raw material and match ratio is determined according to mud configuration program, and according to pulping process flow system Slurry；

B4, carry out trenching construction using mud, and keep mud circulation and quality of mud fluid.

During construction of diaphragm wall, excavating grooving is its critical process, and needs during grooving to realize shield using mud Wall, take slag, cooling and the lubrication function such as drilling tool.Mud should have the stability of physics, the stability of chemistry, suitably flowing Property, the series of properties such as good mud skin Forming ability and suitable density, above-mentioned functions could be met and require.So, science Configuration and the correct key being to ensure that grooving using mud, take top step, can obtain with physical stability, change Learn the mud that stability, proper flow, mud skin Forming ability and suitable density are satisfied by requiring.

Preferably, in described step b, when carrying out trenching construction, including following aspect：

B ' 1, selection chute forming machine；

B ' 2, carry out construction of diaphragm wall using multiple milling slot technique, described multiple milling slot technique is first grooving section The two ends soil body, then excavate the multiple excavation method of the midfeather soil body；

B ' 3, set up finite element analysis model, carry out analogue simulation construction, determine slurry coat method unit weight, make cell wall keep steady Fixed；

B ' 4, the optimum grooving technology according to the step b ' 3 each groove section of determination；

B ' 5, carry out groove section inspection, the grooving credit rating of evaluation groove section；

B ' 6, control sediment thickness, including mud property, cell wall open-assembly time and bottom land borehole cleaning quality, cell wall open-assembly time Control at 36～48 hours, during bottom land borehole cleaning, pump line is sealed with conveyance conduit, using crossover-circulating type method, sediment is suctioned out.

Take aforesaid way, harmony that chute forming machine cut during soil both sides neighbour circle condition can be effectively ensured, make cell wall vertical, Make grab bucket grooving in the state of eating soil resistance equilibrium, or the bucket tooth on grab bucket both sides is all eaten in real soil, or grab bucket both sides Bucket tooth all fall in cavity, it is to avoid grab bucket bucket tooth is eaten in real soil, while falling in cavity；Applied by analogue simulation Work, determines slurry coat method unit weight and cell wall displacement it is ensured that safety, determines optimum grooving technology simultaneously, make slurry coat method unit weight little, The technique that cell wall deformation is little, safety coefficient is larger.

Effective control sediment thickness, traditional construction method is more difficult to put in place deposit control, after leading to bottom land void slag, base The hole excavation stage may lead to cheat inside and outside artesian water from the supply of diaphragm wall bottom, leads to foundation ditch artesian head to be difficult to reduce, to dash forward in hole bottom The security incident such as gush；Later stage may lead to the quality accidents such as structure crack waterproof failure because sedimentation is excessive, take said method, have Effect controls these problems it is ensured that construction safety and construction quality.

Preferably, in described step b4, mud property index is adjusted by test result, keep quality of mud fluid, main bag Include following aspect：

B41, test purify proportion, pH value and the viscosity performance index of mud；

B42, supplement bentonite, soda and CMC composition to purifying in mud, make purification mud substantially recover original shield Wall performance；

B43, mud pit carry out periodic cleaning, so that the larger mud of sand factor can be recycled through process；

B44, regenerated mud is blended with newly mixing mud, produce high specific gravity mud, so that the retaining wall performance of regenerated mud is obtained Improve.

Take aforesaid way, mud and concentration being used in mixed way of mud, the mixing mud that mixing goes out after reclaiming, purifying Performance is relatively stable, more applicable, and also plays preferable result in follow-up work progress.

Preferably, in described step b ' 2, using six milling slot techniques and four milling slot techniques, specifically include Following steps：

B ' 21, the first grooving section two ends soil body, or using having dug behind one end, tripping middle part digs the side of the other end again Method, makes centre leave the partition wall not being mined；

After the completion of b ' 22, two ends are excavated, excavate partition wall；

B ' 23, after projected depth is all dug in two ends and midfeather, then along flute length direction set dig；

B ' 24, while grab bucket is dug along flute length direction set, grab bucket is transferred to and excavates bottom land in groove section projected depth and sink Slag.

Take aforesaid way, first excavate the two ends soil body, so that grab bucket is equalized painstakingly when digging one end, can effectively rectify a deviation, Ensure grooving perpendicularity, after first excavating two ends, dig primarily serving the purpose of of partition wall：Because the length of midfeather opens bucket less than grab bucket Length, grab bucket can cover excavates toward partition wall, and grab bucket equally can be made to equalize painstakingly, and correction is it is ensured that grooving perpendicularity effectively, and along groove Length direction set digs, and can guarantee that groove section laterally has good rectilinearity.

Preferably, the content of described groove section inspection includes the wall of the plan-position deviation, the depth of groove section and groove section of groove section Face perpendicularity.

Preferably, in described step d, in carrying out fabrication of reinforcing cage and hoisting process, comprise the following steps：

D1, set up two sections of processing platforms and be divided into two sections of difference to process nearby steel reinforcement cage, the length of two sections of steel reinforcement cages is respectively Corresponding with groove segment length；

D2, by bottom distributing reinforcement position mark in deck roof, repave bottom layer of the reinforcing steel net, reinforcing bar all puts postwelding, if frame Stud, repaves top mat；

The loop wheel machine that d3, selection are adapted to steel reinforcement cage is lifted.

Preferably, in described step d3, steel reinforcement cage is lifted into groove by the way of integral manufacturing, merogenesis lifting, specifically Comprise the following steps：

D31, crane include main crane and secondary crane, and main crane is hung in lower section by cross-arm, pulley, the several suspension centre of steel wire rope Steel reinforcement cage top, secondary crane is hung in steel reinforcement cage middle and lower part by cross-arm, pulley, the several suspension centre of steel wire rope；

D32, major and minor crane leave the lifting of steel reinforcement cage level after platform simultaneously, and master hangs and gradually rises, and pair is hung to main handling Dynamic, make steel reinforcement cage gradually switch to plumbness by horizontality；

D33, after master hangs and bears total weight, shed pair and hang；

D34, master hang and slowly move near groove section, and by steel reinforcement cage alignment slot section center, master hangs and progressively transfers steel reinforcement cage extremely Groove section bottom, is then led on wall by shelving cross-arm and be fixed on lower section of steel reinforcement cage top；

After d34, the decentralization of lower section steel reinforcement cage put in place, with shelving steel plate, steel reinforcement cage is fixed to notch, recurrence hangs on section reinforcing bar Cage is directed at hypomere steel reinforcement cage under natural plumbness；

D35, steel reinforcement cage surrounding there are are several groups of lengthways main steel bars docking spacing mark tighten connector and be welded H profile steel and connect Head, more again carried steel reinforcement cage, make upper-lower section steel reinforcement cage be in nature plumbness, tighten remaining lengthways main steel bar connector；

D36, mend and set drag hook, transverse steel, built-in fitting, protective layer cushion block etc., finally will be butted under the steel reinforcement cage of view picture Put into groove.

Preferably, in described step e, comprise the following steps：

E1, joint adopt I-shaped steel tank section joint, remove and use brush wall device brush wall again after streaming attachment, make on joint steel plate Mud skin be eliminated；

E2, the length of backbreaking of minimizing groove section, simultaneously after steel reinforcement cage decentralization, have filled the space of steel reinforcement cage joint Entirely；

E3, outside I-steel paste sheet iron, so that the space between I-shaped steel joint and ground-connecting-wall cell wall is filled up；

E4, according to groove section joint whether there is percolating water, carry out closure process；

E5, poured, concrete conduit uses DLC, concrete conduit is inserted into from bottom land 300-500mm, in concrete conduit Two conduits are poured by setting bladders with same speed.

It is a difficult problem that joint is streamed all the time, in diaphram wall digging process, due to backbreaking of junction, and The steel reinforcement cage of subterranean wall is to manufacture according to the framing of groove section again, has the space of 50-70mm between steel reinforcement cage and cell wall simultaneously, because This during concrete casting it is easy to produce around flow phenomenon, this creates impact to the construction of lower groove segment, again shadow simultaneously Ring the stagnant water effect of joint, take aforesaid way, can effectively prevent flow-disturbing phenomenon, neither impact construction, reach preferably simultaneously Stagnant water effect.

Compared with prior art, beneficial effects of the present invention：

1st, pass through to introduce the method for analyzing stability of strength degradation, be calculated cell wall on the basis of finite difference calculus steady Qualitatively safety coefficient, by material parameters modification cycle calculations, not only can obtain limit stress and the large deformation state of cell wall, and And the coefficient of stability of cell wall will be obtained, there is to construction practical advice meaning, its result is simple and practical and meets engineering circles Custom, effectively guarantees that slurry trench stability requires, thus safety, high-quality, quickly completing engineering construction；

2nd, by configuring process and the method for slurry coat method, obtained that there is physical stability, chemical stability, appropriate flow The mud of dynamic property, good mud skin Forming ability and suitable density so as to there is retaining wall, taking the functions such as slag, cooling and lubrication drilling tool, Thus preparing necessary condition for excavating grooving；

3rd, by reasonable, effective trenching construction technique it is ensured that chute forming machine cuts the harmony of both sides neighbour circle condition during soil, make Cell wall is vertical, makes grab bucket grooving in the state of eating soil resistance equilibrium, or the bucket tooth on grab bucket both sides is all eaten in real soil, or The bucket tooth on grab bucket both sides all falls in cavity, it is to avoid grab bucket bucket tooth is eaten in real soil, while falling in cavity, and passes through Analogue simulation is constructed, and determines slurry coat method unit weight and cell wall displacement it is ensured that safety, determines optimum grooving technology simultaneously, make retaining wall The technique that volume weight of slurry is little, cell wall deformation is little, safety coefficient is larger；

4th, traditional construction method is more difficult puts in place deposit control, and after leading to bottom land void slag, the excavation of foundation pit stage may Lead to cheat inside and outside artesian water to feed from diaphragm wall bottom, lead to foundation ditch artesian head to be difficult to reduce, dash forward and the security incident such as gush in hole bottom；Afterwards Phase may lead to the quality accidents such as structure crack waterproof failure because sedimentation is excessive, by effective control sediment thickness, effective control These problems are it is ensured that construction safety and construction quality.

Brief description：

Fig. 1 is the construction flow chart of diaphram wall.

Fig. 2 is the force analysis figure of cell wall stability analyses in soil layer.

Fig. 3 is slurry trench stability and volume weight of slurry graph of a relation.

Fig. 4 is slurry trench stability and mud liquid level height relationships figure.

Fig. 5 is mud configuration programme diagram.

Fig. 6 is pulping process flow figure.

Fig. 7 circulates schematic diagram for mud.

Fig. 8 is six milling slot construction technology precedence diagrams.

Fig. 9 is four milling slot construction technology precedence diagrams.

In figure labelling：The 1- slip wedge soil body, 2- first excavates region, and 3- second excavates region, and 4- the 3rd excavates region, 5- the 4th excavates region, and 6- the 5th excavates region, and 7- the 6th excavates region.

Specific embodiment

With reference to test example and specific embodiment, the present invention is described in further detail.But this should not be understood Scope for the above-mentioned theme of the present invention is only limitted to below example, all belongs to this based on the technology that present invention is realized The scope of invention.

Embodiment 1

The present embodiment is applied in the ultra-deep underground continuous wall work progress of rich water soft clay area.

It is four layers of underground engineering that the present embodiment set the underground space to connect engineering, and excavation of foundation pit depth is 34m, negative one, two Layer foundation ditch is open-cut, minus three, minus four layers of foundation ditch do lid excavation construction using plate in twice is inverse, main body building enclosure adopts 58m Deep underground continuous wall, wall thickness 1.2m, steel reinforcement cage maximum weight 116T, fabric width 4.5～6m, 72 width altogether.Wherein one horizontal or vertical scroll of calligraphy width, Z The horizontal or vertical scroll of calligraphy 4 width, the L horizontal or vertical scroll of calligraphy 4 width.Using H profile steel joint form.8m scope below foundation ditch bottom adopts ground-connecting-wall lattice to reinforce, laterally 1 road diaphram wall is set at interval of 21m, totally 7 roads add up to 21 width.

The geological condition of this engineering is distributed from top to bottom and is followed successively by 5m thickness miscellaneous fill layer, 13m thickness silt, 25m thickness mud Matter clay and silty clay, the thick severely-weathered tufa stone layer of 10m thickness gravel layer (artesian aquifer), 3～5m, basement rock are that middle air slaking are coagulated Grey rock stratum.This project subject structure diaphragm wall penetrates the waterpower connection of artesian water inside and outside cut-out hole in weathered rock formation during artesian aquifer enters System, is forced into iterative structure by pre-buried connector, shear bar and agent structure simultaneously jointly, has gear soil, antiseepage, load-bearing concurrently Function.

As shown in figure 1, rich water soft clay area ultra-deep underground continuous wall construction method, including following multiple steps：

After c, grooving are up-to-standard, carry out brush wall scarfing cinder；

D, make and lift steel reinforcement cage；

Joint between e, backfill grooving pit section, and place concrete conduit；

F, the Commercial Concrete pouring body of wall concrete of use supply；

From the point of view of continuous wall trench underground process, compacted due to stratum soil pressure, pore water pressure, level of ground water and the soil body The impact of factor such as become, during grooving or before body of wall pours, among cell wall plays pendulum, cunning occurs at any time The danger split or cave in.Therefore, in construction, should in advance and must according to the physico-mechanical properties of place soil layer, level of ground water, The factor such as quality of mud fluid and unit groove segment length, carries out stability analyses to cell wall, and takes corresponding retaining wall measure it is ensured that cell wall Stablize.

From the means calculating analysis, analysis cell wall stability mainly has two big class methods, and first kind method is classical Soil mechanics theory, first supposes destroying, then according to static balance condition (polygon of force or power of cell wall by linear or arc line shaped Square balances) try to achieve safety coefficient, obtain the parameters such as simulated mud further, the shortcoming of the method is：Needs do a large amount of simplify and It is assumed that and the mechanical index such as cell wall internal force, deformation can not obtain it is impossible to go deep into guiding construction.Equations of The Second Kind method is based on even The computational theory of continuous mechanics, due to reasons such as load, boundary condition complexity, for numerical computations relative theory calculates, more There is advantage, such as FEM calculation can obtain the mechanical index such as cell wall internal force, deformation, certain technology will be provided to construction Support, but the method also has its shortcoming：Stress, deformation index can not intuitively reflect the extent of stability of cell wall, and conventional is limited First numerical computation method is for Rock And Soil large deformation phenomena simulation less effective.

According to the particularity of geological condition and hydrologic condition, the stable relation of ultra-deep cell wall is to construction quality and construction speed Problem, the quality of mud determines the stability of cell wall it is desirable to engineering circles carry out in-depth study to this again.Diaphram wall Stability primary analysis method mainly have following three kinds：1. according to classical earth pressure theory to different soil, such as clay stratum Or sandy soil stratum, if consider that Effect of Underground Water Level and the gelatification of mud are calculated, in this, as configuration mud Foundation；2. the stabilizing moment after cell wall excavates and the safety coefficient of slip moment are calculated with circular sliding surface, and soil layer is hit by a bullet Property mechanical stress and displacement solution, determine mud severe and mud liquid level；3. according to soil mechanics principle of effective stress and consideration cell wall The tau-effect of stability, calculates the slurry trench stability of different digging time, construction organization is proposed with specific reference to index.

Because ultra-deep underground continuous wall cutting depth is big, boundary condition is complicated, stratum soil pressure, pore water pressure, underground The impact of the factors such as the creep of water level and the soil body is notable, can only obtain qualitative conclusions using soil mechanics traditional counting theory, and limited Differential technique has good adaptability just in these areas, is then increasingly subject to the weight of engineering circles in Geotechnical Engineering Depending on.

The geological condition of the diaphram wall of the present embodiment is distributed from top to bottom and is followed successively by 5m thickness miscellaneous fill layer, 13m thickness powder Sand, 25m thickness silt clay and silty clay, the thick severely-weathered tufa stone layer of 10m thickness gravel layer (artesian aquifer), 3～5m, Basement rock is middle air slaking tufa stone layer.Diaphram wall standard width thickness is 1.2m, and single width width is 4-6m, and maximum weight is about 116T, point two section liftings, underwater grouting C35 concrete.

When carrying out Stability Analysis of Trenches of Diaphragm Wall, native including according to soil mechanics planing theory, taking slip wedge Body is analyzed, and obtains the safety coefficient of slurry trench stability.

In the soil body, Groove Wall Stabilization of Diaphragm Wall, by classical soil mechanics planing theory requirement, takes the slip wedge soil body to carry out Analysis, as shown in Fig. 2 according to resistance to shear of soil equilibrium condition, on cell wall, horizontal stress state can represent as formula 1；

Formula 1：In formula,For cell wall Upper horizontal stress；γ_iFor soil body weighted average unit weight；H_iFor diaphram wall cutting depth；For soil body internal friction angle；c_iFor Soil body cohesion；γ_wUnit weight for water；h_iFor artesian head.

By calculating, it is below earth's surface 6.65m that this engineering ensures that the highest of slurry trench stability cheats outer underground height of water level. Using hole outer foundation ditch periphery arrangement dewatering well auxiliary precipitation, by construction groove section, nearby water level is down under earth's surface 7m to this engineering (former level of ground water is 5m under earth's surface).

On cell wall, active earth pressure is expressed as formula 2；

Formula 2：

On cell wall, mud pressure is expressed as formula 3, formula 3：

Take volume weight of slurry γ_m=12.5kN/m3, maximum cutting depth H=58m.The safety coefficient of slurry trench stability is permissible Definition is as shown in Equation 4；

Formula 4：

Above-mentioned safety coefficient is equal to the regulation of the safety coefficient in specification with regard to two grades of side slopes.For confirmation slurry trench stability reason By analysis result, after the method using numerical computations is analyzed.

The intensity index parameter of the adjustment soil body, including cohesion c and angle of friction φ, obtains safety coefficient F_s.

In Strength Reduction Method, the safety coefficient of slurry trench stability is defined as：When making cell wall just reach critical slope langth, right Soil shear strength carries out the degree of reduction, that is, define the actual shearing strength that safety coefficient is the soil body and folding during critical slope langth Subtract the ratio of rear shear strength, the main points of Strength Reduction Method are constantly intensity index c of the adjustment soil body and φ, respectively obtain formula 5 With formula 6, the c in formula 5_FFor the cohesion after reduction, the φ in formula 6_FFor the angle of friction after reduction, F_trialFor reduction coefficient, when During critical slope langth, the reduction coefficient obtaining is safety coefficient F_s；

Formula 5：c_F=c/F_trial；

Formula 6：φ_F=tan^-1((tanφ)/F_trial)；

When solving safety coefficient, first, set a larger numerical value to cohesion and change inside soil body stress, to find System reaches typical time step Nr of dynamic balance；Then, for given safety coefficient F_s, execute Nr time step, if system is uneven Weighing apparatus power is less than 10 with typical internal force ratio R^-3Then it is assumed that system reaches dynamic balance.If out-of-balance force ratio R is more than 10^-3, then Execution Nr time step, until R is less than 10^-3Exit current calculating, start new round Reduction calculation process.

Set up diaphragm wall and excavate plane strain model, the impact of analysis artesian water and slurry trench stability.

Set up a width diaphram wall excavation plane strain computation model as follows：Geometric model width is 5m, is highly 80m, thickness is 1.2m, totally 1560 units.Wherein left border is symmetrical boundary condition, and excavation width is 0.6m, and depth is 58m, right side applies X to horizontal restraint, the Y-direction horizontal restraint of side applying in front and back, and bottom applies the constraint of X, Y, Z fixed end.Artesian water holds Pressure head is respectively applied on the unit of -5m～-18m and -43m～-53m.In practice of construction, a width diaphram wall is from excavation Terminate to concrete perfusion, total time-consuming is about 36-48 hour, the time is shorter, therefore slurry trench stability analysis does not consider artesian water The fluid structurecoupling problem that pressure release causes, only considers static balance condition.

The impact highly significant to slurry trench stability for the artesian head, the situation with regard to whether there is artesian water in soil layer enters line number Value calculates analysis, draws the engineering execution regularity of common-sense, slurry coat method unit weight takes γ_m=12.5kN/m3, cutting depth takes H= 58m, understands according to calculating analysis, in the groove inside of continuous underground wall between -43m～-58m due to the work of underground bearing water head With will occurring towards the displacement (0.023m) in hole, velocity shows the trend (F that there is quicksand at this_s=1.04), cell wall Stability very low.Numerical result and theory α coefficient coefficient (F_s=1.25) there is certain discrepancy, reason is theory α coefficient During coefficient calculates it is considered to be that overall active earth pressure on cell wall is balanced with mud pressure, and numerical computations are mainly in view of Local stability under artesian water effect for the cell wall.

For relatively having artesian water, excavate in the stratum of no artesian water, in the presence of mud pressure, cell wall will occur Outwardly against trend, mud pressure and periphery soil body passive earth pressure progressively reach balance (F_s=1.92).Therefore, work as stratum Middle there is artesian water situation when, it should be specifically noted that the adjustment of volume weight of slurry and liquid level is it is ensured that slurry trench stability.

In the case of not adopting mud off measure, diaphram wall can be with vertical cut about 2.4m, cell wall horizontal position Move and be about 0.005m.From the point of view of Numerical results, safety coefficient F now_s=2.15, but if continuing to increase cutting depth And not in addition mud off, cell wall horizontal displacement gathers way very fast, and when being such as excavated to -2.8m downwards, its value is 0.1m, will Have a strong impact on slotted eye quality and engineering safety, then take under no mud off measure, critical excavation depth is 2.4m.Due to slotted eye Dig as deep as to -58m it is therefore necessary to adopt mud off method.

Select mud parameter, improve reduction parameter, make slurry trench stability obtain code requirement.

Improve the effect of mud off, mainly sticked by raising mud liquid level, adjustment volume weight of slurry, increase mud The methods such as degree, reduction sand content in mud are realized.In view of the approximation of numerical computations, mainly will be for mud liquid level and mud The selection of slurry unit weight is studied, and mud viscosity, sand content in mud mainly will be ensured by working measure.Mud liquid level, As shown in Figure 3 and Figure 4, volume weight of slurry unit is kN/m to the relation of volume weight of slurry and slurry trench stability³.

As shown in Figure 3 and Figure 4, the safety coefficient of slurry trench stability and volume weight of slurry or mud liquid level is approximate is directly proportional Relation, when volume weight of slurry is 12.5kN/m³, when mud liquid level and ground flush, safety coefficient F_s=1.04；And work as volume weight of slurry For 14.5kN/m³, during mud liquid level 2m above ground level, safety coefficient F_s=2.3.It is extremely difficult to 13kN/m in view of volume weight of slurry³ More than, in order to ensure the stability of cell wall, mud liquid level can be properly increased it is recommended that configuration volume weight of slurry reaches in construction 12.5kN/m³, using leading wall, mud liquid level is lifted 1m, safety coefficient F_sIt is up to 1.4, meet the steady of one-level side slope in specification Qualitative requirement.

From the point of view of continuous wall trench underground process, compacted due to stratum soil pressure, pore water pressure, level of ground water and the soil body The impact of factor such as become, during grooving or before body of wall pours, among cell wall plays pendulum, cunning occurs at any time The danger split or cave in.Therefore, in construction, should in advance and must according to the physico-mechanical properties of place soil layer, level of ground water, The factor such as quality of mud fluid and unit groove segment length, carries out stability analyses to cell wall, and takes corresponding retaining wall measure it is ensured that cell wall Stablize.By the way, introduce the concept of " strength degradation ", be calculated slurry trench stability on the basis of finite difference calculus The safety coefficient of property, by material parameters modification cycle calculations, not only can obtain limit stress and the large deformation state of cell wall, and The coefficient of stability of cell wall will be obtained, there is to construction practical advice meaning, its result will be simple and practical and habit that meet engineering circles Used, effectively guarantee that slurry trench stability requires.

Embodiment 2

During the present embodiment is applied to the configuration of slurry coat method and uses.

The engineering parameter setting in the present embodiment is same as Example 1 with geologic parameter.

During construction of diaphragm wall, excavating grooving is its critical process, and needs during grooving to realize shield using mud Wall, take slag, cooling and the lubrication function such as drilling tool.Mud should have the stability of physics, the stability of chemistry, suitably flowing Property, the series of properties such as good mud skin Forming ability, suitable density, could meet above-mentioned functions require.So, science Configuration and the correct key being to ensure that grooving using mud.

(1) slurrying

Carry out mud plant's arrangement, the ultra-deep underground continuous wall geological condition by being constructed is complicated, and duration pressure is tight, at most When three width diaphram wall trenching constructions simultaneously, the pit capacity containing mud should be able to meet mud during trenching construction and use Amount.The volume calculations of mud pit are as shown in Equation 7；

Formula 7：Qmax=n × V × K

In formula, Qmax mud pit maximum capacity；N grooving number of devices, is 3 when maximum；Every grooving equipment of V The shoveling amount of unit interval, takes 120m3/d；K mud redundancy, takes K=1.5 in the present embodiment engineering.

Carry out plant configuration it is considered to ground-connecting-wall becomes groove depth depth, fabric width, mud amount needed for every width groove is big, recovery Mud has partly to be discarded, and need to lay in certain mud, setting mud pit, slurry tank are as transfer.Plant allocation plan is such as Shown in table 1.

Table 1

Get out raw material and match ratio is determined according to mud configuration program, and carry out slurrying according to pulping process flow.

It is (swollen that mud components make raw material for the excellent bentonite of performance indications, soda, sodium carboxymethyl cellulose and tap water Profit soil:Water=116:950).As shown in Figure 5, it then follows mud configuration program, the parameter combination technology specification of mud system, combination Geological condition and the construction experience of conventional diaphram wall, newly join mud consumption of main materials in the present embodiment and performance indications are divided It is not shown in Table 2 and table 3.

Mud consumption of main materials newly joined by table 2

Mud materials	Bentonite	Soda	CMC	Tap water
					1m³Feed intake (kg)	116	4.5	1	950

Mud property index newly joined by table 3

Project	Viscosity (S)	Proportion	PH value
				Index	21～23	1.06～1.10	7.5～9

Mud Making programme is as shown in fig. 6, first carry out raw material test, then weighs and feed intake, and is respectively put into bentonite and water, mixes Close stirring 5 to 10 minutes, then carry out mud property index determining, standby after swelling 24 hours.

Mud circulating treatment procedure, as shown in fig. 7, utilizing slush pump, fire hose, ball valve switch etc., makes slurrying pond prepare Mud be respectively delivered to the groove section of supply stock tank, pulp storage tank, overfall pond and hot work in progress.The mud warp cementing out in construction Cross desanding device, used according to quality rebuilding or discarded.Geological condition according to this engineering and the construction of conventional diaphram wall Experience, in cyclic process, mud property index is shown in Table 4.

This engineering newly mix mud veclamation, purify after performance indications as follows：

The mud main performance index that table 4 reclaims

Proportion	Viscosity (S)	Sand content (%)	PH value
				1.09～1.14	19～21	3～5	8～9

Carry out trenching construction using mud, and keep mud circulation and quality of mud fluid, mud is adjusted by test result Energy index, keeps quality of mud fluid.

Test purifies the performance indications such as proportion, pH value and the viscosity of mud, because mud is wanted and ground in use Soil, subsoil water contact, and form mud skin in flute wall surfaces, consume the compositions such as bentonite in mud, soda and CMC, mud Part retaining wall performance can be lost.Therefore, circulating mud need to adjust its performance indications according to test result, recovers its original retaining wall Performance.

Supplement the compositions such as bentonite, soda and CMC to purifying in mud, make purification mud substantially recover original retaining wall Performance, by the test purifying the performance indications such as proportion, pH value and the viscosity of mud, understanding that in purification mud, main component is swollen Profit soil, the degree of the consumption such as soda and CMC, supplement mud components method be to purify supplement in mud bentonite, soda and The compositions such as CMC, make purification mud substantially recover original retaining wall performance.

It is less than 1.05g/m in mud pit mud balance³When being unsatisfactory for code requirement, often square mud adds 1-2kg blanc fixe Stir, mud balance can increase 0.02-0.05g/m in 2-4h³.When in mud pit, mud viscosity is less than 18s, often side Mud adds 2-5kg sodium carboxymethyl cellulose, and mud viscosity can increase 2-5s in 2-4h.

Mud pit carries out periodic cleaning, so that the larger mud of sand factor can be recycled through process, due to underground even Continuous wall need to pass through silty sand ground and fine sand layer, and when grooving is to layer of sand, in mud, sand factor can increase sharply, and takes no action to mud All become useless slurry.For this reason, when recycling mud, sand factor is more than with 5% mud, every Fang Xin slurry plus 1kg are industrial Soda, the sand in mud can precipitate.Mud pit is carried out with cleaning in regular 5-10 days, the larger mud of such sand factor is through processing Can recycle.In addition, also can be purified using native slag bolter, hydrocyclone, double-deck reciprocating sieve multiple stage separation.

Regenerated mud is blended with newly mixing mud, produces high specific gravity mud, so that the retaining wall performance of regenerated mud is improved, Fresh mud balance typically below 1.05 it is difficult to when meeting layer of sand trenching construction cell wall stability mud balance need to be reached More than 1.1 requirement.If directly configuration is hyperbaric newly mixes mud, material cost is higher.Although regenerated mud is not so good as new Mix the superior performance of mud, but, by newly mixing mud is blended together use together by regenerated mud, the height of economy just can be produced Ratio weighted mud, also improves the retaining wall performance of regenerated mud.

Draw out from above-mentioned analysis, after purification mud balance is larger, viscosity is less, and it is larger to fluctuate, be therefore directed to and reclaim Mud property has formulated special mud match ratio, and its proportion is less, viscosity is larger, concrete cooperation when performance such as table 5, table 6 With shown in table 7；

Table 5 mud match ratio

Bentonite (kg)	Tap water (kg)	Soda (kg)	CMC(kg)
				80	1000	0.9	2.3

Table 6 mud property index

Proportion	Viscosity (S)	Sand content (%)	PH value
				1.04	49	0	9

Table 7 concentrates mud and recovery mud presses 2:Its performance is tested after 3 ratio mix and blends

Proportion	Viscosity (S)	Sand content (%)	PH value
				1.06～1.08	25～27	2～4	8～9

From table 5, table 6 and table 7 as can be seen that by mud after reclaiming, purifying and concentration being used in mixed way of mud, mixing goes out Mixing mud performance relatively stable, more applicable, and also play preferable result in follow-up work progress.

It should be noted that fresh mud mixing water must carry out physical and chemical index detection when using subsoil water, mineral become Point, the index such as acid-base value need to meet requirement it is ensured that mud forms mud skin retaining wall.

Embodiment 3

The present embodiment was used in the construction stage that grooving is excavated.

Choose suitable chute forming machine, the mode chute forming machine according to excavating has：Multi-head spiral bores, rushes grab bucket, impact drill, bull Bore and wheel milling formula, disk milling formula (milling type) etc..

Carry out construction of diaphragm wall using multiple milling slot technique, for ensureing that chute forming machine cuts the equal of the neighbour circle of both sides during soil condition Weighing apparatus property, vertical to guarantee cell wall, construction of diaphragm wall is intended using job-hopping method, according to the A/F of groove segment length and chute forming machine, determines Open-width of informing against and closure width.With, during grab bucket grooving, slotted eye to be made is vertical, one of most critical is intended to make grab bucket to eat soil resistance equal Grooving in the state of weighing apparatus, or the bucket tooth on grab bucket both sides is all eaten in real soil, or the bucket tooth on grab bucket both sides all falls in cavity, Never grab bucket bucket tooth, while eating in real soil, falls in cavity, according to this principle, unit groove section tentatively drafts employing " six milling slot technique " and " four milling slot technique ", excavation order is respectively as shown in Figure 8 and Figure 9.

When unit groove section being excavated using six milling slot techniques, first dig the first excavation region 2 of end side, Then excavate the second excavation region 3 of the other end, then excavate the 3rd of middle part and excavate region 4, finally excavate another again Region 6 and the 6th excavation region 7 are excavated in 4th excavation region the 5, the 5th of a part.

When unit groove section being excavated using four milling slot techniques, first excavate the first excavation region of end side 2, then excavate the second excavation region 3 of the other end, then the 3rd excavation region 4 at initial excavation end is excavated in tripping middle part, Finally excavate the 4th excavation region 5 of midfeather.

Take the above-mentioned first grooving section two ends soil body, digging the mode of midfeather, grab bucket can be made equal painstakingly when digging one end Weighing apparatus, can rectify a deviation it is ensured that grooving perpendicularity effectively.

After the completion of taking two ends to excavate, excavate the mode of partition wall, because the length of midfeather opens bucket length less than grab bucket, Grab bucket can cover excavates toward partition wall, grab bucket equally can be made to equalize painstakingly, correction is it is ensured that grooving perpendicularity effectively；

After projected depth is all dug in two ends and midfeather, then dig along flute length direction set, two ends and partition wall are dug in grab bucket When, the male and fomale(M＆F) that formed because the perpendicularity of grab chute forming is different repair smooth it is ensured that groove section laterally has good straight line Property.

While grab bucket is dug along flute length direction set, grab bucket is transferred to and in groove section projected depth, excavates bottom land sediment.Root According to the probe being arranged on hydraulic grab, at any time deflection situation is reflected by popping one's head in line on the computer of driver's cabin, drive The person of sailing starts the hydraulic pressure push pedal on hydraulic grab according to four direction dynamic skew situation on computer and carries out dynamic correcting, by becoming Constantly carry out accurate dynamic correcting it is ensured that the vertical precision of ground-connecting-wall in groove.

Set up finite element analysis model, carry out analogue simulation construction, determine slurry coat method unit weight, make cell wall keep stable, Set up finite element analysis model according to six milling slot techniques and four milling slot technique respectively as follows：Geometric model width For long 20m, wide 10m, highly for 80m, totally 21120 units, the vertical placement of geometric model, wherein left border apply X to water Prosposition moves, and excavation width is 6m, and depth is 58m, and right side applies X to horizontal restraint, and front side is symmetrical border, and rear side applies Y-direction Horizontal restraint, bottom apply X, Y, Z fixed end constraint, ground floor artesian head, second layer artesian head be respectively applied to -5m～- On the unit of 18m and -43m～-53m, slurry trench stability analysis does not consider the fluid structurecoupling problem that artesian water causes, and only considers quiet Dynamic balance condition, slurry coat method unit weight takes γ_m=11kN/m³, cutting depth takes H=58m.

Optimum grooving technology is determined according to step said process, when slurry coat method unit weight takes γ_m=11kN/m³When, cell wall is protected It is fixed to keep steady, and cell wall X-direction maximum displacement grabs slotted eye bottom for the 6th, and numerical value is 8mm, and cell wall Y-direction maximum displacement is grabbed for the 6th Slotted eye bottom, numerical value is 21mm, is in safe condition (safety coefficient is more than 1)；

Such analysis process considers the presence of 2 layers of artesian water, and in moment unloading phase, pore water is negative to cell wall to layer of sand Pressure condition, favourable to slurry trench stability, but long-time not closed trench hole, after negative pore water pressure disappears, layer of sand easily caves in.

Four grab in trenching construction simulation process, and slurry coat method unit weight takes γ_m=12kN/m³, cutting depth takes H=58m, and Six grab grooving technology compares, when slurry coat method unit weight takes γ_m=12kN/m³When, cell wall could keep stable, and cell wall X-direction is maximum Displacement grabs slotted eye bottom for the 4th, and numerical value is 10mm, and cell wall Y-direction maximum displacement grabs slotted eye bottom for the 6th, and numerical value is 30mm, (safety coefficient is more than 1) in a safe condition；

Find out from analysis result, six grab grooving technology with four grab grooving technology compared with, slurry coat method unit weight is little, cell wall become Shape is little, and safety coefficient is big, and ground adaptability is strong, and four to grab grooving technology speed of application fast.Therefore, in the present embodiment to geology The poor soil layer of condition selects six to grab grooving technology, and grooving technology is then grabbed using four in the preferable stratum of geological conditions.

Carry out groove section inspection, the grooving credit rating of evaluation groove section, the content of groove section inspection include the plan-position of groove section, The wall perpendicularity of the depth of groove section and groove section.

The instrument of groove section inspection and method are specific as follows：

A, groove section plan-position separate-blas estimation：Survey groove section end positions, two ends absolute fix line and this groove section with plummet Between framing line, deviation is groove section plan-position deviation；

B, groove section depth detection：With lining rope survey three positions in groove section left, center, right bottom land depth, three positions average Depth is the depth of this groove section；

C, groove section wall measuring for verticality：Groove is scanned with ultrasound wall instrument respectively in groove section on the position of left, center, right three Wall wall, wall bottommost bulge quantity or amount of recess (to lead metope for the scanning datum level) ratio with groove section depth in scanning record It is wall perpendicularity, the meansigma methodss of three positions are groove section wall average vertical degree；

D, the method for expressing of groove section perpendicularity：Groove section perpendicularity=X/L；Wherein：X- wall maximum concavo-convex amount；L- is groove section Depth.

Control sediment thickness, including mud property, cell wall open-assembly time and bottom land borehole cleaning quality, cell wall open-assembly time controls At 36～48 hours, during bottom land borehole cleaning, pump line is sealed with conveyance conduit, using crossover-circulating type method, sediment is suctioned out.

The engineering diaphragm wall that the present embodiment sets and agent structure form the overlapping common stress of wall, and air slaking in toe of wall insertion are coagulated Limestone 1m, if sediment thickness control is not in place, bottom land void slag is blocked up, and the excavation of foundation pit stage may lead to cheat inside and outside artesian water from even The supply of continuous wall bottom, leads to foundation ditch artesian head to be difficult to reduce, and dashes forward and the security incident such as gush in hole bottom；Later stage may be because settling excessive leading to The quality accidents such as structure crack waterproof failure.

Impact diaphragm wall sediment thickness principal element have following some：Mud property, cell wall open-assembly time and bottom land are clear Hole quality.

Reduce diaphragm wall cell wall open-assembly time, it is 1m that diaphragm wall is entered rock depth optimization, the too high position of local rock formation intensity Put and guarantee not less than 50cm, by optimizing into rock depth and selecting suitable grooving equipment, this engineering continuous wall trench time base Within this control 36～48h, the grooving time is comparatively preferable.

Adopt large-scale vacuum in this engineering, after the decentralization of concrete delivery pipe puts in place, will before casting concrete, by pump line with Conveyance conduit is tightly connected, and will cheat bottom sediment using crossover-circulating type method and suction out, and on the one hand guarantee that most of sediment is sucked out, remain simultaneously Remaining a small amount of sediment floats through mud flowing rear overhang, then fast pouring concrete is it is ensured that bottom land concrete compaction.

Embodiment 4

The present embodiment is applied in fabrication of reinforcing cage and the work progress of lifting.

The engineering parameter setting in the present embodiment is same as Example 1 with geologic parameter, draws reinforcing bar according to engineering parameter The specification of cage, the long 57.7m of steel reinforcement cage, width is 4.5～6m, and weigh 116T most, using integral manufacturing, under the mode of merogenesis lifting Put to bottom land, the long 37m of upper section steel reinforcement cage, weigh about 74T, the long 20.7m of lower section steel reinforcement cage, weigh about 42T, suspender and suspension centre weigh about 4T.

Lifted from double-machine lifting crane method.Hang from 320T crawler crane in conjunction with real-time site condition master, pair hangs selection 150T crawler crane meets requirement.

Fabrication of reinforcing cage, in units of unit groove section, sets up two sections of processing platforms and steel reinforcement cage is divided into two sections of difference nearby Processing, processing platform is set up by channel-section steel, the platform top surface discrepancy in elevation<5mm, is first with red before fabrication of reinforcing cage by bottom distributing reinforcement position Paint is drawn in deck roof in advance, repaves bottom layer of the reinforcing steel net, reinforcing bar all puts postwelding, if bearing rod, repaves top mat.

Steel reinforcement cage setting accuracy controls：Strictly carry out reinforcing bar setting-out by design drawing, according to setting-out list, correctly arrange steel Muscle, reinforcing bar connector, and firm welding.Wall absolute altitude is led in measurement, the length of the correct hangs muscle that converts, and it is long that steel plate, hangs muscle are shelved in welding Degree is accurate, and should check and accept.Unit groove section developed width and molding rebar sizes, zero difference should be checked before fabrication of reinforcing cage Could upper mounting plate make；After muscle cage completes, because ground-connecting-wall is as deep as 58m, using the I-shaped steel joint that rigidity is larger, reinforcing bar Cage entirety tolerance standard need to improve than code requirement, needs rebar sizes to steel reinforcement cage, diameter, bar spacing, pre-buried Part etc. endures strict scrutiny, and fabrication of reinforcing cage tolerance is shown in Table 8.Quality must be met through three level testings after fabrication of reinforcing cage Standard can be lifted by crane into groove after requiring.

The making tolerance of table 8 steel reinforcement cage

Steel reinforcement cage installs entirety must be straight, and deviation cannot be greater than 0.1%. and avoids breaking cell wall in decentralization process, or no Method is transferred.Steel reinforcement cage thickness should meet design protection layer requirement simultaneously.Width：Phase need to be inserted in the non-width steel reinforcement cage one end that first opens In the H profile steel joint of adjacent width of having constructed, eight prefixs must be made in therefore this termination of steel reinforcement cage, apart from adjacent H profile steel position control In 5cm about.Length direction：Length of reinforcing cage should be less than effective groove depth 30cm, and in the range of the 50cm of steel reinforcement cage bottom Without arrangement transverse steel cage, lead to steel reinforcement cage cannot transfer to bottom land to avoid bottom land irregular.

In the present embodiment, because ground-connecting-wall participates in later stage stress, diaphragm wall is reserved with the reinforcing bar being connected with floor and plugs into Device, during installation of embedded parts, management personnel must be checked, and should control in 1cm for floor connector site error Within.While checking the relative position of built-in fitting, also need to calculate steel reinforcement cage top steel according to the designed elevation of built-in fitting Steel reinforcement cage top rebars, during decentralization steel reinforcement cage, are positioned it is ensured that under reality by the theoretical absolute altitude of muscle by survey crew Put absolute altitude consistent with theoretical absolute altitude, it is to avoid connector and pre-embedded steel slab dislocation.

Main loop wheel machine type selecting：Main loop wheel machine adopts 320T pedrail crane, brachium 66m, and the biggest lifting capacity is 155.7T, secondary loop wheel machine choosing Type：Pair hangs 150T crawler crane, brachium 37m, biggest lifting capacity 77.8T.

By the way of integral manufacturing, merogenesis lifting, groove is entered to steel reinforcement cage, reinforcement cage hoisting is in steel reinforcement cage by steel reinforcement cage The process of plumbness is switched to by horizontality on platform for making, completes with two cranes.For guaranteeing to lift by crane safety, reinforcing bar Cage enters groove by the way of integral manufacturing, merogenesis lifting, above cuts steel reinforcement cage and is about 37m, the heaviest 80t, and a lower section steel reinforcement cage is about 19m, the heaviest 36t.Step includes hanging down cuts steel reinforcement cage and hangs section steel reinforcement cage and integrally enter groove.

Hang down and cut steel reinforcement cage, main crane hangs in lower section of steel reinforcement cage top by cross-arm, pulley, the several suspension centre of steel wire rope, Secondary crane is hung in steel reinforcement cage middle and lower part by cross-arm, pulley, the several suspension centre of steel wire rope.Major and minor crane is simultaneously by steel reinforcement cage level After platform is left in lifting, master hangs and gradually rises, and pair is hung and moved to main handling, makes steel reinforcement cage gradually switch to vertical configuration by horizontality State.After master hangs and bears total weight, shed pair and hang.Master hangs and slowly moves near groove section, by steel reinforcement cage alignment slot section center, Master hangs progressively decentralization steel reinforcement cage and to groove section bottom, is then led on wall by shelving cross-arm and be fixed on lower section of steel reinforcement cage top.

Hang and cut steel reinforcement cage, entirety enters groove, after lower section steel reinforcement cage decentralization puts in place, with shelving steel plate, steel reinforcement cage is fixed to Notch, recurrence hangs on section steel reinforcement cage and be directed at hypomere steel reinforcement cage under natural plumbness, when steel reinforcement cage docks it should be noted that：Under slow Put a section steel cage, so that each group lengthways main steel bar is matched and make in order, steel reinforcement cage surrounding is had several groups of lengthways main steel bars docking spacing mark twist Tight connector is simultaneously welded H profile steel joint, more again carried steel reinforcement cage, makes upper-lower section steel reinforcement cage be in nature plumbness, tightens Remaining lengthways main steel bar connector；Benefit sets drag hook, transverse steel, built-in fitting, protective layer cushion block etc., finally will be butted into the steel of view picture Groove is put under muscle cage.

The wall wall top surface flatness of leading of code requirement is 5mm, will check again and lead 4 fulcrums on wall before steel reinforcement cage hangs Absolute altitude, accurately calculate hangs muscle length it is ensured that error is in allowed band.Before steel reinforcement cage hangs, ultrasound wave inspection need to be carried out again Survey cell wall perpendicularity.Detection section includes horizontal three sections and longitudinal two ends termination, totally five sections.Steel reinforcement cage hangs into groove When, do not allow to impact by force into groove, note steel reinforcement cage foundation ditch face simultaneously and meet native face, forbid to put back.Shelving a channel-section steel must root Factually survey and lead the welding of wall absolute altitude.

For the lifting of deformed bar cage, answer the setting of reasonable Arrangement suspension centre, it is to avoid the generation of amount of deflection, and during plus The inspection of strong weld quality, it is to avoid omit solder joint.After steel reinforcement cage just hangs platform, should stop lifting by crane, note having seen whether Abnormal phenomena occurs, if having, can be welded reinforcing immediately.According to site operation experience, steel reinforcement cage must be to flat before lifting Face size is checked by drawing diagonal.

Suspension hook is accurately positioned it is ensured that lifting by crane the balance of process steel reinforcement cage, checks suspension hook welding quality；Cleaning reinforcing bar cage body is miscellaneous Thing, falls during preventing lifting and hurts sb.'s feelings, and checks hoisting fixture and steel wire rope；Steel reinforcement cage is hung ground 50cm by two cranes Afterwards, again, being checked, after not having abnormal conditions, next step of being allowed for access, until steel reinforcement cage is holded up completely to each position；Steel reinforcement cage In erection process, main the hanging of special messenger commander need to be set and hang with pair, master hangs should steadily, at a slow speed during being hung in lifting with pair, phase interworking Close, it is to avoid pull steel reinforcement cage, prevent two crane unbalance stress or steel reinforcement cage deformation.Adopt 6 suspension ring in steel reinforcement cage top board, often Side 3, each suspension ring adopts the round steel of Φ 32 to make, and for preventing suspension ring top from rupturing, ties up weldering one in suspension ring arc part and hangs Ring is it is ensured that force request.

Embodiment 5

The present embodiment is applied to the selection of joint and joint is prevented streaming in work progress.

In construction of diaphragm wall, groove section joint is always important sport technique segment in constructing, and enjoys design and constructs Personnel pay attention to.But, many diaphram walls occur concrete stream, the line of rabbet joint percolating water the problems such as, all relevant with groove section joint, Sometimes irretrievable loss can also be caused.

The requirement of construction of diaphragm wall butt joint form：

(1) excavation of next unit groove section must not be hindered；

(2) concrete perfusion must not hole between joint construction thing and cell wall or flow to groove section from the bottom of joint Outward；

(3) joint should be able to bear coagulation earth lateral pressure, and do not bend and deform；

(4) purpose of design according to structure, being capable of stress between transfer unit groove section play expansion joint

Effect；

(5) construction technology is simple, low cost.

In order to ensure being connected between groove section and groove section, there is good sealing and globality, should be according to the purpose of diaphragm wall Select suitable joint form, seam crossing shearing resistance can be increased, and not permeable leak is principle.

Underground continuous wall groove segment joint form is varied at present, substantially can be divided into joint of precast piles, fore shaft pipe joint With shaped-steel joint three major types.The present embodiment is used I-steel as joint form, and accordingly formulation is prevented streaming measure.

The requirement of construction of diaphragm wall butt joint form：

(1) excavation of next unit groove section must not be hindered；

Effect.

(5) construction technology is simple, low cost.

Underground continuous wall groove segment joint form is varied at present, substantially can be divided into joint of precast piles, fore shaft pipe joint With shaped-steel joint three major types.This section is compared to three kinds of joint forms first, then, according to No. 4 line train east of Hangzhou Subway The Zhan Xi square underground space connects the engineering characteristic of engineering ultra-deep underground continuous wall, and selected I-steel is as joint form, and phase Should formulate and prevent streaming measure.

Shaped-steel joint generally uses the thick steel plate of 8mm or 10mm to make, and its specification such as cross steel plate, channel-section steel, I-steel etc. are pressed Design requirement is selected.Generally, shaped-steel joint makes at the scene, installs.I.e. live blanking, Site Welding, Assembling, Flitch should keep straight, and size strictly presses design requirement, and its soldered is full, highly, width should meet relevant steel construction weldering Connect code, should be taken into account the hot response of steel construction during welding, take reasonable welding procedure and step, its direct shadow of quality making Ring bending resistance and the water resistance of joint.

Integral with steel reinforcement cage welding white silk after the completion of section steel manufacture, under normal circumstances, diaphram wall cage bar protects thickness Spend for 50-70mm, therefore may produce during filling concrete and stream, therefore need to stop in a phase groove section wing plate both sides welding and starch iron sheet, Prevent from streaming in concrete entrance shaped steel, cause difficulty to the second stage of groove section, due to the heavier-weight of shaped steel, therefore in lifting process In, its lifting safety will be paid special attention to, especially connect width construction when, because both sides are asymmetric, more it is noted that.

For the mud skin being attached on shaped steel, must remove clean before the decentralization of the second stage of groove section steel reinforcement cage, concrete way is It is close to panel position with special brush wall device along shaped steel slowly to wash away, go out till groove do not carry mud mark secretly until brush wall device.

Due to the present embodiment the underground space connect engineering ultra-deep underground continuous wall as deep as 58m, engineering geology and the hydrology ground Matter complicated condition, when from groove section joint, can select following three kinds of joint forms：Joint of precast piles, fore shaft pipe joint and I-shaped steel joint.

But the diaphram wall for complicated condition, ultra-deep, not only can be produced using locking notch pipe joint form in construction The certain difficulty of life, and economic benefit can be affected.Junction block time of tube drawing in construction is difficult to preferably grasp, extubation time The relatively early then fragile interface having poured groove section, extubation time is later, can pull out not outlet pipe because concrete and junction block cling. Even more so for ultra-deep ground-connecting-wall, body of wall is deeper, and it is bigger that locking notch pipe acts the resistance pulling out, if extubation time is not controlled, Just further increase the resistance of tube drawing, be easy to that the phenomenon that junction block can pull out out occurs.

Directly it is embedded in diaphragm wall after joint of precast piles grooving, is not recycled, decrease and extract operation, in joint Reinforcing bar is identical with the arrangement of reinforcement of diaphragm wall, does not affect the stress conditions such as the bending strength of building enclosure itself, but needs configuration special Bored machine.Reinforced concrete joint is prefabricated component, the overall progress of its Influence of production engineering, the same underground of joint of precast piles , with deeply, the preparation joint quality of a 20m having poured is up to 60T it is necessary to be entered using the method for segmentation prefabrication and lifting for diaphragm wall Row construction.

Consider processing, connect, lifting aspect convenient, this engineering has selected rigidity preferable I-shaped steel tank section joint.Work Word steel joint is a kind of joint form that construction of diaphragm wall is commonly used, and is particularly suitable for the poor stratum of geology.Want size accurate during use Really, firm welding, should be able to bear lateral pressure during filling concrete.

For ultra-deep underground continuous wall, groove section joint prevents that stream is a difficult problem all the time, excavated in diaphram wall Cheng Zhong, due to backbreaking of junction, and the steel reinforcement cage of subterranean wall is to manufacture according to the framing of groove section, steel reinforcement cage and groove simultaneously There is the space of 50-70mm, it is easy to produce around flow phenomenon, this is to lower groove segment therefore during concrete casting between wall Construction create impact, affect the stagnant water effect of joint simultaneously again.

First have to use brush wall device brush wall again, to remove the mud skin on joint steel plate after attachment is streamed in removing.Brush wall device is adopted Hang brush with bias, to ensure steel brush face and the close contact of joint face, reach and clean effect with water.Follow-up groove section is dug to designed elevation, Clean the heavy quarrel on leading width joint face or mud skin with water, brush wall number of times is no less than 10 times, and no mud is on the hairbrush face of brush wall device Only.As laced belt mud is excessive during swiping, can be carried out it is ensured that clear joints using hydraulic giant butt joint brush, it is to avoid generation The possibility of percolating water.

Reduce the length of backbreaking of groove section, simultaneously after steel reinforcement cage decentralization, the space of steel reinforcement cage joint is filled completely.One Kind of method is using packed clay filled, but when depth is larger, and it is slower that filling is difficult closely knit, speed of application；Another side Method is exactly to dispose joint case, but when joint case length is big, certainly will be difficult to pull out.During case above, this project construction The clay that is packed in bag is filled with and is tamped with crane suspension heavy weight (joint case or self-control iron block).In terms of work progress, only Want sand pocket filling closely knit, enough reaction of bearings can be provided to steel plate for sealing water, can effective control concrete stream.

The thick sheet iron of patch 1m width, 0.2mm outside I-steel, during concrete perfusion, makees in concrete lateral pressure To be opened with lower sheet iron, fill up the space between I-shaped steel joint and ground-connecting-wall cell wall, and effectively prevent concrete from bypassing joint With cell wall gap.

Find there is Seepage as after excavating, leak stopping should be carried out immediately, visually its water leakage degree difference takes corresponding measure, Method for blocking is as follows：

When having micro leak, can be repaired using double-quick cement；

2. when leak is more serious, available double-quick cement is blocked, and uses flexible pipe drainage simultaneously, waits after hardening of cement from drain Inject chemical grout sealing leak stopping in pipe, carry out chemical grouting；

3. to larger leakage scenarios, it is possible to produce when a large amount of soil sands leak into, first by leak source soil or quick cement back-pressure, Prevent a large amount of sands from oozing out.Adopt two fluid grouting (waterglass and cement) to process at the back side of diaphram wall simultaneously.

Diaphragm wall is poured using double conduit method, and conduit is inserted into from bottom land 300～500mm, should before concrete perfusion Bladders is set in conduit, to play impermeable role.In cast, conduit insertion concrete depth should remain at 2～6m. Horizontally disposed generally 1.5m between conduit, maximum no more than 3m, not should be greater than 1.5m away from groove section end.When concrete is poured into a mould, two Tremie placing speed should be consistent it is ensured that filling concrete highly steadily rises, it is to avoid causes vexed pipe and because concrete turns over not Come up, cause clay seam phenomenon.

For guaranteeing to have buried 3 grouting pipes in quality every width diaphragm wall at diaphragm wall toe of wall, two near joint, depth With diaphragm wall with deep, complete 1 month about in construction of diaphragm wall, toe of wall slip casting is carried out to diaphragm wall it is ensured that bottom land concrete is closely knit, often , to grouting equipment pressure stability in 3Mpa, according to data statisticss, every grouting amount is all in 0.5～1m for root pipe³Left and right, sediment Control preferably.

Claims

1. a kind of rich water soft clay area ultra-deep underground continuous wall construction method is it is characterised in that comprise the following steps：

A, preparation of construction, including assembling groover, setting mud system and surveying and locating, also include steady to groove inside of continuous underground wall Qualitative be analyzed study；

After c, grooving are up-to-standard, carry out brush wall scarfing cinder；

D, make and lift steel reinforcement cage；

Joint between e, backfill grooving pit section, places concrete conduit and is poured；

F, the Commercial Concrete pouring body of wall concrete of use supply；

A1, according to soil mechanics planing theory, take the slip wedge soil body outside diaphragm wall cell wall to be analyzed, obtain slurry trench stability Property safety coefficient, the described slip wedge shape soil body be diaphragm wall cell wall, soil mass sliding surface and cell wall depth composition the soil body；

2. rich water soft clay area according to claim 1 ultra-deep underground continuous wall construction method is it is characterised in that in step In a4, described mud parameter includes mud liquid level, volume weight of slurry, mud viscosity and sand content in mud.

3. rich water soft clay area according to claim 2 ultra-deep underground continuous wall construction method is it is characterised in that described step In rapid b, prepare slurry coat method and comprise the following steps：

B3, get out raw material and match ratio is determined according to mud configuration program, and carry out slurrying according to pulping process flow；

4. rich water soft clay area according to claim 1 ultra-deep underground continuous wall construction method is it is characterised in that described step In rapid b, when carrying out trenching construction, including following aspect：

B ' 1, selection chute forming machine；

B ' 2, carry out construction of diaphragm wall using multiple milling slot technique, described multiple milling slot technique is first grooving section two ends The soil body, then excavate the multiple excavation method of the midfeather soil body；

B ' 3, set up finite element analysis model, carry out analogue simulation construction, determine slurry coat method unit weight, make cell wall keep stable；

B ' 6, control sediment thickness, including mud property, cell wall open-assembly time and bottom land borehole cleaning quality, cell wall open-assembly time controls At 36～48 hours, during bottom land borehole cleaning, pump line is sealed with conveyance conduit, using crossover-circulating type method, sediment is suctioned out.

5. rich water soft clay area according to claim 3 ultra-deep underground continuous wall construction method is it is characterised in that described step In rapid b4, mud property index is adjusted by test result, keep quality of mud fluid, mainly include following aspect：

B42, supplement bentonite, soda and CMC composition to purifying in mud, make purification mud substantially recover original retaining wall Energy；

B44, regenerated mud is blended with newly mixing mud, produce high specific gravity mud, so that the retaining wall performance of regenerated mud is improved.

6. rich water soft clay area according to claim 4 ultra-deep underground continuous wall construction method is it is characterised in that described step In rapid b ' 2, using six milling slot techniques and four milling slot techniques, specifically include following steps：

B ' 21, the first grooving section two ends soil body, or using having dug behind one end, the method that tripping middle part digs the other end again, make Centre leaves the partition wall not being mined；

B ' 24, grab bucket along flute length direction set dig while, grab bucket is transferred to and in groove section projected depth, excavates bottom land sediment.

7. rich water soft clay area according to claim 6 ultra-deep underground continuous wall construction method is it is characterised in that described groove The content of section inspection includes the wall perpendicularity of the plan-position deviation, the depth of groove section and groove section of groove section.

8. the rich water soft clay area ultra-deep underground continuous wall construction method according to one of claim 1-7 it is characterised in that In described step d, in carrying out fabrication of reinforcing cage and hoisting process, comprise the following steps：

D1, set up two sections of processing platforms and be divided into two sections of difference to process nearby steel reinforcement cage, the length of two sections of steel reinforcement cages respectively with groove Segment length corresponds to；

D2, by bottom distributing reinforcement position mark in deck roof, repave bottom layer of the reinforcing steel net, reinforcing bar all puts postwelding, if bearing rod, Repave top mat；

9. rich water soft clay area according to claim 8 ultra-deep underground continuous wall construction method is it is characterised in that described step In rapid d3, steel reinforcement cage is lifted into groove by the way of integral manufacturing, merogenesis lifting, specifically includes following steps：

D31, crane include main crane and secondary crane, and main crane is hung in lower section of reinforcing bar by cross-arm, pulley, the several suspension centre of steel wire rope Cage top, secondary crane is hung in steel reinforcement cage middle and lower part by cross-arm, pulley, the several suspension centre of steel wire rope；

D32, major and minor crane leave the lifting of steel reinforcement cage level after platform simultaneously, and master hangs and gradually rises, and pair is hung and moved to main handling, Steel reinforcement cage is made gradually to switch to plumbness by horizontality；

D33, after master hangs and bears total weight, shed pair and hang；

D34, master hang and slowly move near groove section, and by steel reinforcement cage alignment slot section center, master hangs and progressively transfers steel reinforcement cage to groove section Bottom, is then led on wall by shelving cross-arm and be fixed on lower section of steel reinforcement cage top；

After d34, the decentralization of lower section steel reinforcement cage put in place, with shelving steel plate, steel reinforcement cage is fixed to notch, recurrence hangs on section steel reinforcement cage and exists It is directed at hypomere steel reinforcement cage under natural plumbness；

D35, steel reinforcement cage surrounding is had dock spacing mark several groups of lengthways main steel bars tighten connector and be welded H profile steel joint, Again carried steel reinforcement cage again, made upper-lower section steel reinforcement cage be in nature plumbness, tighten remaining lengthways main steel bar connector；

D36, mend and set drag hook, transverse steel, built-in fitting, protective layer cushion block etc., finally put into being butted under the steel reinforcement cage of view picture Groove.

10. rich water soft clay area according to claim 1 ultra-deep underground continuous wall construction method is it is characterised in that described In step e, comprise the following steps：

E1, joint adopt I-shaped steel tank section joint, remove and use brush wall device brush wall again after streaming attachment, make the mud on joint steel plate Skin is eliminated；

E2, the length of backbreaking of minimizing groove section, simultaneously after steel reinforcement cage decentralization, fill the space of steel reinforcement cage joint completely；

E5, poured, concrete conduit uses DLC, and concrete conduit is inserted into from bottom land 300-500mm, arranged in concrete conduit Two conduits are poured by bladders with same speed.