CN106522235A - Narrow site deep foundation pit excavation supporting construction method - Google Patents

Abstract

The invention relates to a narrow site deep foundation pit excavation supporting construction method, and belongs to the field of building construction. The construction method includes the following contents that the depth of a foundation pit is 12.1 m; the depth of underground water in a the foundation pit is 30 m; the depth of underground water outside the foundation pit is 30 m; and the coefficient for importance of a supporting structure is 1.0. The construction method comprises the steps that (1) a soil nailing and anchor spraying method is adopted for slope supporting of the foundation pit; (2) a support pile and anchor cable method is adopted for non-sloping space supporting of a forwarding station and a gallery; and (3) the support pile and anchor cable method is adopted for foundation pit supporting. According to the narrow site deep foundation pit excavation supporting construction method, it is guaranteed that surface water outside the foundation pit does not flow into the foundation pit, accumulated water inside the foundation pit and on a slope face is drained out of the foundation pit in time, and stagnantblocked water on a shallow layer of the side wall of the foundation pit can be smoothly drained out; and a retention wall is arranged on the periphery of the foundation pit, it is guaranteed that rainwater cannot wash the slope, and it is guaranteed that the accumulated water can be drained out in time.

Description

Narrow and small place deep pit digging construction method for supporting

Technical field

The invention belongs to the realm of building construction, it is adaptable to narrow and small place, the confined space, surrounding buildingses environment are complicated, engineering The deep pit digging supporting of complex geologic conditions.

Background technology

Under the background of China's rapid economic development, building trade also occurs in that the development of great-leap-forward.Due to China it is few People is more, and per capita soil is Economization on land, wants house to space no more than the l/10 in the per capita soil in the whole world, to old Area, many skyscrapers is wanted to rise sheer from level ground in room.Appropriate development multilamellar and high level, to the development of aerial and underground, are to solve China The important outlet of bar of shortage of land resource.As city-building is on the middle and senior level and high-rise building is emerged in multitude, deep-foundation pit engineering It is more and more.Meanwhile, intensive building, the underground installation of the foundation ditch around of big depth so that slope excavation pit this One conventional art can no longer meet the needs of modern city and towns construction, therefore, deep pit digging causes the wide of each side with supporting General attention.

Form of the excavation of early stage frequently with slope, later with the increase of cutting depth, slope space of planes is restricted, and produces Go along with sb. to guard him excavation.So far, go along with sb. to guard him pattern and be developed to tens of kinds.From for foundation pit enclosure mechanism, foundation pit enclosure method Development have slope to excavate earliest, then have cantilever to go along with sb. to guard him, internal stay（Or draw anchor）Go along with sb. to guard him, combined go along with sb. to guard him.Slope is excavated to be needed There is larger work surface, and excavation amount is larger.

The content of the invention

In order to be applied to narrow and small place, the confined space, surrounding buildingses environment are complicated, the complicated deep basal pit of engineering geological condition Excavation supporting, the present invention propose the narrow and small place deep pit digging construction method for supporting of short time limit and construction safety.

Technical scheme：Narrow and small place deep pit digging construction method for supporting, the foundation ditch cross-sectional shape is in Concave shape, mean depth 12.2m, innermost depth are 18.8m,

Excavation slope adopts " soil nailing+spray anchor " supporting.Transfer station, gallery take propping up for " support pile+anchor cable " without slope space Shield.Pattern foundation pit supporting structure adopts support pile+anchor pole；

Pit earthwork is excavated observes scientific construction method with pattern foundation pit supporting structure, and " fluting is first supportted strict implement, is first supportted and is dug afterwards, and layering is opened Dig, forbid to backbreak " principle, per layer is cut the earth less than 2m, first digs out the nail Construction scope of operation, and nail Construction is finished, and reaches one Determine intensity, then carry out large area excavation, last layer supporting reaches intensity, just carry out next layer of excavation.

Described " soil nailing+spray anchor ' foundation pit supporting method：Soil nailing arrangement principle：Soil nailing is divided to two kinds of specifications 12m, 9m, arrangement side Formula is laid for Flos Mume, floor height spacing 1.5m, level interval 1.2m, and the first floor pushes up 2.5m away from slope, away from soil nailing in the range of bottom of foundation ditch 3m Using 9m specifications, remaining adopts 12m specifications.

Nail Construction technique：

1st, soil nailing is prefabricated, and with the reinforcing bar of 22 mm of diameter, spacing is every 2m welding to medium-height trestle；

2nd, soil nailing pore-forming, using down-the-hole drill hole, aperture 100mm, bore angle are 15 °, keep drilling rod stable, in case disturbing Hole is stepped on greatly, borehole cleaning after pore-forming, is carried out；

3rd, soil nailing is laid, and hole-sealing grouting, soil nailing are used stop grouting plug sealing of hole, then carry out pressure water flooding mud, slip casting side after placing Formula be bottom slip casting, serosity by slip casting pore from bottom hole start to aperture filling fill out.When serosity is filled to aperture from bottom, also At least 2 times pressurizations need to be carried out（Pressure is 0.3Mpa）, it is ensured that serosity is crowded with hole walls.The fullness coefficient that slurry is injected into hole must 1 must be more than.

Jet-anchor execution technique：

1st, slope is manually repaiied, the slope before spraying anchor dug machinery, using slope is manually repaiied, evens mechanical teeth impression out, it is ensured that Slope Degree；

2nd, bar-mat reinforcement establishment, using the reinforcing bar colligation of diameter 10 into the reinforced mesh of 150mm spacing, is laid in slope surface, steel Muscle mesh sheet upper strata arranges stiffener, and diamond shaped arrangement, stiffener intersection point are located at soil nailing position, stiffener and soil nailing L Shape hook is welded in one, forms overall anchor structure；

3rd, concrete ejection, using air compressor machine by sand, cement, the mixture of rubble are sprayed in domatic, shower nozzle apart from it is domatic not More than 80cm, layering injection, it is ensured that thickness is not less than 10cm；The soil nailing is the reinforcing bar of 22mm and to medium-height trestle group by diameter Into reinforcing bar length direction is provided with a pair pairs of medium-height trestles at interval of 2m；It is described to include stake body to medium-height trestle, have on stake body Soil nailing draw-in groove along its length, the section semicircular in shape of soil nailing draw-in groove.Respectively there are a colligation groove, support in the two ends of stake body There are three spacing legs on body.The edge of spacing leg is curved, and the summit of three spacing leg curved edges is located at together On one circumference.The spacing leg of two of which is located on straight line, and another spacing leg is vertical with the two spacing legs.

Along foundation ditch longitudinal direction both sides slope, using the method for protecting support of soil nailing+spray anchor.Reinforcement fabrication of the nail Construction using C16 Form, using P.O42.5 cement slips casing by pressure, add early strength agent, it is ensured that soil nailing early stage reaches intensity, accelerate foundation pit construction and enter Degree.The soil nailing combined bolting and shotcrete mechanism of action is that soil nailing anchor pole forms an enlarged footing consolidation by slip casing by pressure twice, in hole Body, with the common stress of the soil body, while anchor pole is welded by reinforcement with reinforced mesh, the outer side spray anchor of reinforced mesh forms one Hard outer containment vessel, anchor pole cooperatively form overall supporting construction with spray anchor face.

4.2 support piles+cable bolting method

First carry out support pile to set before excavation of foundation pit, be respectively provided with the support pile of three types:A type stakes, the long 32.2m of stake, stake footpath 1m, pile spacing 1.5m；Type B stake, the long 22.5m of stake, stake footpath 0.8m, pile spacing 1.2m；B type stakes, the long 15.1m of stake, stake footpath 0.8m, stake Spacing 1.2m；A circle Guan Liang is respectively provided with each stake top；

A type stakes be arranged in cutting depth more than 17m upright shoveling foundation ditch periphery, spacing 1.5m, 36 altogether, Type B stake arrangement In the upright shoveling foundation ditch periphery of cutting depth 10-17m, spacing 1.2m, 60 altogether；B type stakes are arranged in cutting depth 8-10m Upright shoveling foundation ditch periphery, spacing 1.2m, 5 altogether, A types stake top arrange 1100*600 Guan Liangs, Type B b types stake top arrange 900*600 Guan Liangs, all support pile Guan Liangs connect to form a rigidity entirety, increase the stability in the large of supporting construction.

Ensure that stake can play the effect of overall opposing soil pressure.Supporting pile driving construction is finished after reaching intensity, carries out supporting Stake top Guan Liang is constructed, and adopts two kinds of specification Guan Liangs, respectively 1100*600 and 900*600 according to different stake types.Due to base Hole depth is deeper, is more preferably to resist soil body lateral pressure, it is ensured that deep pit monitor, arranges one anchor every 3m in Excavation Process Rope, anchor cable adopt P.O42.5 cement mortars high-pressure slip-casting at twice, maintenance to carry out stretch-draw anchor, ground floor after reaching certain 15MPa Tensioning is completed, and can carry out next layer of earth excavation.

Support pile+cable bolting method：The anchor cable adopts a branch of steel strand wires, and steel strand wires one end is pre-buried by pore-forming slip casting In deep soil, steel strand wires other end connection locking device, a prestressing force is applied in steel strand wires by tensioning, steel strand wires pass through Rigging acts on backing plate, and waist rail, waist rail act on support pile, it is ensured that support pile does not occur when by soil body horizontal peristaltic forces Displacement and destruction.

Anchor cable arrangement principle：Anchor cable is divided into 3 ropes and 5 ropes according to steel strand wires radical, is divided into 22m anchor cables according to anchor cable length, 25m anchor cables, 30m anchor cables, the stake of A types are 4 row's 30m cable boltings, and anchor cable horizontal spacing 1.5m is an anchor formula, it is vertical between Away from 3.5m, first floor anchor cable is 3 row's 25m cable boltings apart from 2.8m at the top of foundation ditch, Type B stake, and anchor cable horizontal spacing 2.4m is two One anchor formula, level interval 3m, apart from 3.5m at the top of foundation ditch, the stake of b types is 2 row's 22m cable boltings to first floor anchor cable, between anchor cable horizontal Away from 2.4m, it is two anchor formulas, level interval 3m, first floor anchor cable is apart from 3.5m at the top of foundation ditch.

Anchor cable construction technique：

1st, anchor cable is prefabricated, and anchor cable adopts 1860 grades of high strength steel strands.The cutting length of steel strand wires is：Anchor cable length+anchorage thickness + jack active length.According to design requirement rope number when anchor cable is prefabricated, lower good high strength steel strand, with sleeve pipe parcel steel strand wires certainly By section, and the coating butter on steel strand wires free segment.To prevent slip casting rear slurry bonding free segment, so as to ensure non-anchored section Freely extend, casing length is equal to design freedom length.Anchoring section carries out oil removal treatment, ensures between steel strand wires and serosity Adhesion strength.Using using PE Grouting Pipes, point once grouting pipe and secondary grouting pipe, once grouting pipe are communicated to bottom to anchor rope grouting （100～200mm is preferably away from bottom hole）, the Grouting Pipe of secondary grouting should do one meter long in the range of anchoring section every two meters Floral tube, floral tube eyelet be φ 8mm, in order to the dispersion of serosity, bottom of the tube is tightened with iron wire, tapping with adhesive tape wrap up with Anti- once grouting serosity is entered.To ensure steel strand wires at hole position center, one localizer should be set every two meters.Steel strand wires slip casting Pipe is integrally bundled into a branch of using localizer.

2nd, anchor cable pore-forming：Using full-sleeve anchor cable rig, bit diameter is 150mm.20 ° of angle, using mud off into When drilling machine drills, drilling rod needed for drilling by anchorage cable design length is put neatly, and drilling rod is finished, and hole depth is also just in place.

3rd, anchor rope grouting：Slip casting adopts special grouting pump, and the pressure gauge of grouting pump should be through checking, and reading can be correctly anti- Reflect grouting pressure.Serosity used by slip casting should be in strict accordance with match ratio Site.Serosity is with mix with when forbidding using placing Between long serosity.First time normal pressure grouting, grouting pressure are 0.5Mpa.Slip casting quantity is measured using hole depth and is noted with computational theory Slurry amount double control.Slip casting first is advisable less than 1 meter with closing anchoring section and invading freedom length.Dredge using high-pressure blast after grouting Logical Grouting Pipe, it is ensured that not plugging during second slip casting.After first time grouting initial set 24h, secondary grouting can be carried out.Secondary grouting Grouting pressure be preferably 2.0Mpa.Aperture sets stop grouting plug, keeps pressure 5～8 minutes, using the slabbing action of high-pressure slip-casting, makes The diameter of anchoring body becomes big, increased the radial compressive stress in soil, while make anchoring body obtain coarse surface, so as to improve anchor Cohesive force between bar and the soil body, improves the bearing capacity of anchor cable.The situation that special messenger observes dewatering well, first row slip casting should be arranged during slip casting When should also be noted that the situation of change on ground, should stop operation immediately if any abnormal conditions, ascertain the reason and take corresponding measure.

4th, waist rail is installed：Waist rail is made using being welded with connecting plate in the middle of two 28b I-steel, and anchor cable is from two I-shapeds Steel intermediate gap is passed through then anchor cable connecting portion installs special backing plate, and anchorage, intermediate plate form the anchor cable system of complete set System.

5th, anchorage cable stretching：After slip casting finishes 5～10 days, anchoring body intensity is not less than the 75% of design strength more than 15MPa When, can tensioning, handling waist rail surface anchor cable aperture before tensioning first well makes which smooth, it is to avoid tension stress concentrate, cushioning- 300 × 300 × 16 steel plate, carries out prestretching with the pulling force of 60kN.Design requirement tensile load will reach design pulling force, and lock Load is design pulling force 75%, therefore locking plate is not put at anchor head during tensioning, tensile load up to after design pulling force, off-load to 0, Anchor head assigns locking plate again, and ability tensioning is to locking load.In stretching process, tensile load classification is carried out, every grade of loading grade observation In time, surveying the displacement of reading anchor head should not be less than 3 times.When tensioning grade reaches design pulling force, kept for 15 minutes, and in observation Anchor head displacement 3 times is read in interior survey, and survey reading shift value no more than 1mm just calculates displacement and tends towards stability every time, and which becomes otherwise to continue observation Tend towards stability and can continue the tensioning of anchor cable in position.

Another kind of structure of the anchor cable is, including push rod, churning drilling rod, single direction thrust ball bearing, bearing block, axial nozzle, Radial nozzles and tungsten bur；The push rod is a multidiameter, and the push rod axial passage of insertion is provided with multidiameter；Multidiameter Big end bore design has trapezoidal thread, and the axle with single direction thrust ball bearing inner hole is respectively arranged with multidiameter small end is cylindrical Neck and the external screw thread coordinated with churning drilling rod；Single direction thrust ball bearing inner ring is engaged with the axle journal of push rod, outer ring and bearing block Inner hole；Push rod is connected with churning drilling rod after installing bearing and bearing block again；Churning drilling rod be shaft-like structure, churning drilling rod Inside offers the churning drilling rod axial passage of eccentric insertion, and one end bore design of churning drilling rod has female thread and push rod External screw thread is matched, makes both be connected, and push rod axial passage and churning drilling rod axial passage connect；The other end of churning drilling rod It is designed to linear mode on double inclined plane, double inclined plane and is disposed with multiple tungsten burs, the nearly bibeveled end outside cylinder of churning drilling rod Face offers upper groove and low groove up and down respectively, and churning drilling rod axial passage is higher by the bottom land of upper groove, upper groove axial end Equipped with the axial nozzle connected with churning drilling rod axial passage, low groove bottom land is provided with and is connected with churning drilling rod axial passage in face Radial passage, on the end face of radial passage be equipped with radial nozzles；Radial direction gyration aperture is left between inner hole of bearing seat and push rod are cylindrical, Axial gap is left between bearing block end face and push rod step end face；It is provided with push rod is cylindrical and is connected with borer drill rod for push rod The symmetrical flat face of clamping is installed.

The totally-enclosed dash water discharge technology of foundation ditch

As foundation depth is deeper, any surface water or subsoil water are all fatal for deep pit monitor, and the present invention takes Totally enclosed construction technology ensures outside foundation ditch that stream does not enter foundation ditch to surface water, inside foundation ditch and domatic hydrops discharge foundation ditch in time, The backwater of foundation pit side-wall shallow-layer can smooth discharge, foundation ditch periphery arranges waterwall, and the through-hardening in the 4m wide scopes, it is ensured that earth's surface Runoff and ground sweat will not enter foundation ditch, the domatic upright wall whole suspended net shotcrete of foundation ditch surrounding, it is ensured that rainwater will not wash away side Temporary drain sump, during every layer of earth excavation, is dug in slope angle, it is ensured that hydrops can be discharged in time in slope, bottom of foundation ditch, Dig to bottom of foundation ditch, stay and set 30cm hand excavation's layers, and excavated after the completion of the formal gutter sump in hole bottom again, dig One section, pour one section, it is ensured that foundation ditch will not expose outside.Last excavation of foundation pit is finished, and hole bottom is all closed, and bottom surrounding is formed Overall integrate draining net, sets up suction pump, arranges special messenger to draw water.

Fig. 1 is the structure chart of anchor pole in the present invention.

Fig. 2 is the structure chart of long spray pawl or short spray pawl in the present invention.

Fig. 3 is the front view in the present invention to medium-height trestle.

Fig. 4 is the left view in the present invention to medium-height trestle.

Fig. 5 is the use state figure in the present invention to medium-height trestle.

Fig. 6 is the structural representation of soil nailing in the present invention.

Fig. 7 is reinforcing bar binding structure schematic diagram in the present invention.

Fig. 8 is foundation pit enclosure wall（Side slope）Top horizontal displacement monitoring method of polar coordinates calculates figure.

In figure, 1, adapter sleeve, 2, connecting hole, 3, large aperture spray road, 4, operation groove, 5, bearing, 6, axle journal, 7, bearing Seat, 8, external screw thread, 9, female thread, 10, anchor pole, 11, small-bore spray road, 12, long spray pawl, 13, short spray pawl, 14, shallow grooves, 15, Drill bit, 16, cone, 17, deep groove, 18, connection ring, 19, hook, 20, chain, 21, hook box, 22, stake body, 23, colligation groove, 24th, spacing leg, 25, soil nailing draw-in groove, 26, reinforcing bar, 27, to medium-height trestle, 28, permeable hole, 29, surface layer, 30, longitudinally reinforced steel Muscle, 31, horizontal stiffener, 32, concrete layer, 33, reinforced mesh, 34, cross-connection point.

Specific embodiment

The technological process of the present invention：The artificial broken pile head concrete Guan Liang of surveying setting-out support pile construction is applied The work ground floor earthwork side slope scope of operation excavates ground floor excavation area supporting soil nailing prefabricated first layer excavation area Shield soil nailing is installed ground floor excavation area reinforced mesh and installs ground floor excavation area anchor cable waist rail installation ground floor Excavation area anchor cable prefabricated first layer excavation area anchor cable pore-forming ground floor excavation area anchor cable once grouting ground floor Excavation area anchor cable secondary grouting ground floor excavation area anchorage cable stretching.

Foundation ditch is calculated：The foundation ditch maximum cutting depth is below ground 17.2m, and the synthetic determination base pit engineering grade is I Level, takes important coefficient 1.1；Remaining side wall refers to surrounding enviroment practical situation, if safe class is II grade, takes important coefficient 1.0；

Slope face, soil nailing combined bolting and shotcrete wall calculate, H=12.1m, forbid preloading, the outer 20KPa of 2m in the 2m of foundation ditch top.

【Basic parameter】

Foundation depth：12.1m；

Groundwater depth in foundation ditch：30m；

The outer groundwater depth of foundation ditch：30m；

Supporting construction important coefficient：1.0；

Soil nailing partial safety factor for load 1.25；

Pulling capacity of soil nail safety loading coefficient：1.6；

Whole slide temperature safety coefficient：1.3.

【Slope line parameter】

Floor projection is 6.1m, and upright projection is 12.1m, and inclination angle is 63 °.

Preloading, the outer 20KPa of 7m are forbidden in pile-anchor retaining face, H=17.2m in the 7m of foundation ditch top.

Using software for calculation：Manage positive deep basal pit 7.0 to calculate foundation ditch and selected foundation pit supporting method to be soil nail wall+stake The foundation pit supporting method of anchor.

Surveying setting-out

Support pile construction survey unwrapping wire：Establish plant area control net after, then carry out the surveying and lay out of support pile point position, according to Fender pile piling construction requires that the setting-out same day needs drilled pile position, and carries out labelling, as site machinery is rolled back and forth, for quilt The stake position control point of breaking-up needs setting-out again.

Earth excavation surveying setting-out：Earth excavation unwrapping wire, requires according to foundation ditch slope, calculates slope and backs down digging line coordinates, with entirely Instrument of standing releases angular coordinate, fixes stake position, then spreads out line with white lime.Unwrapping wire must carry out interior industry work, it is ensured that the standard of calculating Really property, to prevent error, needs many people to adjust repeatedly.Due to cutting the earth for slope, not only need to control bench crest, the gradient, bench toe Need also exist for control.Bottom of slope line traffic control needs to carry out survey and set when digging, and digging process first digs a low-angle slope, cuts the earth with reference to layering Depth, calculates bottom of slope coordinate, makes bottom of slope coordinate on domatic, then uprightly cuts the earth to relevant position.

Deep basal pit elevation is surveyed and is set：As foundation depth is deeper, the measurement of higher degree of early stage can only be carried out with level gauge, cutting depth surpasses Crossing 5m must then carry out elevation transmission, and due to earth work, mechanical work is constantly rolled, and carrying out transmission every time can increase very big Workload, while measurement turns station to be more at most easy to cause accumulated error, this deep basal pit to carry out the measurement of higher degree using total powerstation, profit With vertical control point known to scene and the discrepancy in elevation of measuring point, the measurement of elevation is very easily carried out by calculating then, in coordinate The measurement of higher degree can be just carried out while measurement, makes work efficiency be greatly improved.

Supporting pile driving construction

Shown in Fig. 6, in the present invention, soil nailing is the reinforcing bar 26 of 22mm and medium-height trestle 27 constituted by diameter.Reinforcing bar length direction per A pair pairs of medium-height trestles are provided with every 2m；It is shown in Fig. 3, Fig. 4, Fig. 5, described to include stake body 22 to medium-height trestle, on stake body 22 There are soil nailing draw-in groove 25 along its length, the section semicircular in shape of soil nailing draw-in groove.Respectively there is a colligation groove at the two ends of stake body 23, there are three spacing legs 24 on stake body.The edge of spacing leg is curved, and the top of three spacing leg curved edges Point is on same circumference.The spacing leg of two of which is located on straight line, and another spacing leg is spacing with the two Leg is vertical.

Support pile construction technology process：Excavate stock tank slurry ditch steel reinforcement cage prefabri cation configuration mud surveying setting-out Embedded casing pore-forming borehole cleaning in place hangs steel reinforcement cage perfusion concrete chisel pile crown Guan Liang construction.

（1）Excavate stock tank when note position choose, can neither from pile driving position too away from, be not easy to mud circulation, can not Close to stake too, with mortar leakage prevention, while the water source and mud supply convenient transportation during work progress is considered.

（2）Steel casing diameter for constructing should be greater than a footpath 10cm, and length is not less than 1 meter.Casing is noted when embedded Central point is overlapped with stake position central point

（3）When steel reinforcement cage is prefabricated, reinforcing bar spreading had not only been saved the duration but also can guarantee that construction quality, within 23m using being mechanically connected Steel reinforcement cage takes once prefabricated integral hoisting, and the steel reinforcement cage for being longer than 23m is taken and is divided to two sections of liftings, middle using positive and negative silk braid cylinder company Connect, during this requires steel reinforcement cage process of binding, every section of steel reinforcement cage cage bar spacing is consistent.Joint location must stagger simultaneously, connect Head is preferably arranged on structural elements stress in tensile reinforcement smaller part position, when needing to arrange joint at heavily stressed position, in same company The joint percentage rate of section nipple is connect no more than 50%.

（4）Mud configuration typically can select plasticity index and be more than 25, and particle diameter is viscous more than 50 less than the clay content of 0.074mm Matter soil slurrying, when mud its performance indications of the clay soil modulation using poor-performing are undesirable, can mix in mud Enter Na2OH3（It is commonly called as ground caustic or soda）、NaOH（Sodium hydroxide）Or bentonite powder is improving mud property index.General carbon The incorporation of sour sodium is about 0.1 ~ 0.4 of mud soil amount in hole

（5）When rig is laid, it should be noted that the rig centre of gyration is alignd with pile center, error is not more than 10mm, and meets specification And design requirement.Ensure rig substructure horizontal positioned, it is ensured that borehole perpendicularity.Drilled pile is reached in adjacent studs using every pile driving construction Carry out drilling construction to after 70% design strength again.Rig should adopt the slow-speed of light pressure to ensure borehole perpendicularity when spudding in, to be drilled Can pressurize after entering certain depth speed-raising, and grasp the different stratum of formation variation rule at any time and select different the pressure of the drill and drilling speed

（6）Borehole cleaning immediately after Completion of Drilling Hole, it is ensured that sediment thickness is not more than 200mm, and acceptance(check) hangs steel reinforcement cage in time.Using When crane transfer and lifting steel reinforcement cage, deformation should be prevented, reinforcement protective measure is taken in advance to being likely to result in flexural deformation position. Once should at the uniform velocity, slowly lift by crane during lifting, prevent flexural deformation during lifting.Collision free casing and hole wall during placement, prevent Only aperture debris are fallen in hole.Positioned by designed elevation, it is in place after fix immediately

（7）Concrete perfusion must be carried out to conduit conscientiously and double check in advance.First checks conduit whether gas leakage, broken Damage；Second, under enter conduit before to carefully measure, it is ensured that catheter length through conscientiously calculating, to determine and enter position under conduit；3rd, Under enter hole inner catheter mouth and will meet design specification requirement, generally 50cm away from hole bottom distance；Personal management's pipe is set in filling process Inside and outside concrete surface height, subtracts length of tube to determine, meets pipe laying depth all the time not less than 2m and no more than the specification of 6m will Ask, firmly prevent as depth of tremie causes catheter blockage too much or broken pile is formed due to the too shallow lift-off concrete surface of buried depth. It is when lifting intrusion pipe, preferably slow.According to design requirement, per superfilled 0.5m chisels out superfilled pile head to enter after earth excavation Next procedure is constructed.

（8）Code requirement is pressed before Guan Liang construction, concrete superfilled pile head is cut, according to design drawing colligation Guan Liang reinforcing bar, Mould, casting concrete treat that Guan Liang intensity reaches the 70% of design, can carry out follow-up earth excavation.

（9）Pile integrity detection should be carried out after the completion of supporting pile driving construction（Small strain is detected）.

Earth excavation is constructed

Earth excavation construction technology process：Surveying setting-out, dig the ground floor mask earthwork, artificial Xiu Po, dig the earthwork in the middle of foundation ditch, Dig the 2nd ~ 6 layer of earthwork, drainage trenching, artificial clear bottom, foundation ditch check of foundation subsoil.

1st, surveying setting-out is first carried out before earth excavation, according to the coordinate points in construction drawing, at the scene setting-out, carries out mark Note, spills excavation line with white lime；

2nd, ground floor earth excavation：Earth excavation is excavated using section gap, 10～20m of section length.Overall foundation ditch is accumulative total Length 120m, point six sections of excavations.Per section is first dug foundation ditch peripheral part, i.e., first dig out anchor cable, nail Construction face, begins to immediately prop up Shield engineering construction.While the earthwork is stage excavation, monolayer cutting depth 1.5m～2m often excavates one layer of one layer of soil nailing of construction or pre- Stress anchor cable or anchor pole, each layer is excavated 0.3～0.5m under soil nailing and the prestress anchorage cable scope of operation, upper strata rod member injecting cement paste and Jetting cement surface layer reaches the 40% of design strength, for can excavate lower floor's earthwork after prestress anchorage cable tensioning fixation.Just carry out down One layer of earth excavation；

3rd, manually repair slope, mechanical execution is due to having mechanical teeth, and loosens the earthwork, and machinery is difficult the palm for the gradient Control, must manually be repaiied slope behind the big face of mechanical equivalent of light excavation；

4th, gutter is excavated：Foundation depth is deeper, and construction period is longer, must intercept water measure in slope top setting, protect before excavation of foundation pit The outer rainwater in card hole does not flow into foundation ditch.Bottom is cheated after per layer of excavation simultaneously and scrapes out certain slope, one temporary drain is set in bottom of slope, Rainwater inside foundation ditch is collected effectively, it is ensured that rainwater will not soak whole foundation ditch；

5th, 2-6 layers earth excavation construction method is with first time earth excavation；

6th, last 30cm carries out artificial clear bottom, in case disturbance foundation ditch original soil layer；

7th, during every layer of earth excavation, muck haulage hill gradient is deepened constantly to adjust with foundation depth, it is ensured that vehicle transport is pacified Entirely.

Excavated using section gap, 10～20m of section length.Foundation ditch peripheral part is first dug, mid portion is dug afterwards, i.e., is first dug Go out anchor cable, the nail Construction surface layer earthwork, after not affecting its construction, dig the mid portion earthwork again.Stage excavation, monolayer cutting depth 1.5m～2m, often excavates one layer of construction one layer of soil nailing or prestress anchorage cable, each layer excavate soil nailing and prestress anchorage cable 0.3～ 0.5m, upper strata rod member injecting cement paste and jetting cement surface layer reach the 40% of design strength, can for after prestress anchorage cable tensioning fixation Excavate lower floor's earthwork.Automobile is unloaded coaling-base's foundation ditch and is dug to close design bottom absolute altitude by layer and section；Bottom of foundation ditch collection row is carried out subsequently Water system is constructed, and last 30cm carries out artificial clear bottom.In digging process, muck haulage ramp is progressively adjusted according to excavation of foundation pit depth simultaneously It is whole, it is ensured that vehicle muck haulage safety.

In digging process, should assign, the excavation route and cutting depth of commander's excavator, and according to Drawing pulverized limestone indicates the position of campshed, and at classification excavation spills again excavation line, excavates in strict accordance with classification Construction drawing is constructed.Run into abnormal conditions to stop excavating, ascertain the reason in time, never blindly excavate and barbarous construction, forbid to surpass Dig and digging machine breaks stake.

As the change of bottom of foundation ditch absolute altitude is complicated, dig to absolute altitude change location, note surveying setting-out monitoring at any time, indoors The work of interior industry is carried out in advance, change location coordinate is calculated, gray line is spread at scene, and carry out and tell somebody what one's real intentions are, large area mechanical equivalent of light excavation, while Cooperation is manually cleared up, it is ensured that accurately, do not backbreak excavation of foundation pit position.Foundation ditch discrepancy in elevation larger part, using multiple stage mechanical engagement, Soil-earthwork of cutting the earth-get rid of is transported, and is cooperated, it is ensured that without preloading in the range of the side 2m of hole.

In Excavation Process, to avoid, the local soil body is soft to cause dump truck to subside, and adopts hair to soft soil part Stone is changed to be filled out.

Waterwall, gutter are set in foundation ditch surrounding, it is ensured that the outer water of foundation ditch may not flow into foundation ditch, while waterproof cloth is laid in, Burst weather condition is run into, is covered in domatic the taking for having not enough time to do supporting temporarily, while bottom of foundation ditch has often excavated one layer, At hole bottom, temporary drain sump is set.

Soil nailing jet-anchor execution

Soil nailing jet-anchor execution technological process：Line setting soil nailing position, prefabricated soil nailing, rig pore-forming in place, soil nailing install, once Slip casting, secondary grouting, reinforced mesh establishment welding, domatic spray anchor；

1st, soil nailing makes and lays：Soil nailing pore-forming adopts down-the-hole drill hole, aperture 100mm, and bore angle is -15 °, boring procedure Rate of penetration is adjusted according to soil property situation, it is ensured that do not step on hole, while guaranteeing rig stability, prevent aperture disturbance too big, cause Rotten hole.In soil nailing prefabrication process, spacing 2m is arranged to medium-height trestle, it is ensured that soil nailing can be placed in hole centre position after laying.

2nd, slip casting：Must be conscientious according to design requirement in construction, charge ratio is strictly controlled, and is taken according to construction needs Measure guarantees the mobility and denseness of serosity, adds early strength agent in serosity, it is ensured that soil nailing enters working condition early.Slip casting side Formula be bottom slip casting, serosity by slip casting pore from bottom hole start to aperture filling fill out.When serosity is filled to aperture from bottom, treat After once grouting initial set, also need repeatedly to be pressurizeed（Pressure is 0.3Mpa）, it is general to be no less than 2 times, it is ensured that serosity is crowded with holes Wall.The fullness coefficient that slurry is injected into hole have to be larger than 1.Slurry should stir exist side by side and use, before starting slip casting, halfway Pause or operation need to use water flushing line after finishing.

3rd, before pore-forming, hole position should be made according to design requirement and makes labelling and numbering.The tolerance of hole position is not more than 150mm, the inclination deviation of pore-forming are not more than ± 3 °, aperture tolerance+20mm, -5mm, and hole depth tolerance+ 200mm, -50mm.When barrier is met during pore-forming need to adjust hole position, the original safe coefficient of supporting must not be damaged.

4th, jetting cement THICKNESS CONTROL mark is first buried before working out bar-mat reinforcement, the embedded mesh sheet of spacing 2m fixes nail, and bar-mat reinforcement will Fixation, while adding 1m width pressure network reinforcing bars in Po Ding, reinforced mesh bar gauge spacing must is fulfilled for requiring, due to layering Excavate, levels lapped length of steel bar need to meet code requirement.After bar-mat reinforcement is worked out, stiffener construction is carried out, strengthened Reinforcing bar is welded with L-shaped hook with soil nailing, and weld length, welding quality meet code requirement.

5th, facing concrete injection：To control the thickness of concrete, respective markers should be done in side slope before jetting cement, as control Concrete protects thickness mark.Concrete ejection thickness 10cm, is sprayed at twice, after ground floor injection surface layer solidification, is carried out down One layer of injection.Simultaneously because stage excavation, levels reinforced mesh needs overlap joint, and lower floor's bar splicing must be reserved in course of injection Joint., from domatic 60 100cm, it is closely knit to guarantee jetting cement surface layer and the soil body to answer continuous adjustment angle for concrete spraying machine jet. After jetting cement final set 2h, water seasoning is answered.

Anchor cable or anchor bolt construction

Anchor cable construction technological process is：Line setting anchor cable position, prefabricated anchor cable, rig pore-forming in place, anchor cable are installed, are once noted Slurry, secondary pressure slip casting, reinforced mesh establishment welding, domatic spray anchor, waist rail fabrication and installation, anchorage installation, anchor cable maintenance, anchor cable Pre- tensioning, anchorage cable stretching.

The drill rod end of rig is connected with the adapter sleeve 1 of the anchor cable shown in Fig. 1 by screw thread, and 1 middle part outer wall of adapter sleeve sets There is operation groove 4, for card wrench operated when installing adapter sleeve, adapter sleeve one end is provided with for the brill with rig operation groove 4 The threaded connection hole 2 of bar connection, the other end of adapter sleeve 1 are provided with the external screw thread being connected with anchor pole 10 and the axle journal 6 for installing bearing, Bearing 5 coordinates on axle journal 6 and bearing block 7, and adapter sleeve axle center is provided with large aperture spray road 3, large aperture spray road 3 and anchor pole 10 11 insertion of small-bore spray road, anchor pole one end is threaded connection with adapter sleeve, and the anchor pole other end is provided with drill bit 15, near boring 15 anchor pole outer wall is provided with shallow grooves 14 and deep groove 17, on the anchor pole bar wall of scrobicula groove location opens up spout, sprays Mouth is provided with short spray pawl 13, and spout is opened up on the anchor pole bar wall of deep groove position, and spout is provided with long spray pawl 12, and anchor pole inner chamber is opened It is provided with the eccentric small-bore spray road of insertion.

The long spray pawl is made up of connection ring 18, hook 19, chain 20, hook box 21, and hook box 21 is welded as one with anchor pole Body, connection ring 18 are welded with hook box 21, and one end of chain 20 is connected with connection ring 18, and the other end of chain 20 is connected with hook 19.

The short spray pawl is identical with long spray pawl structure, and except for the difference that the chain of short spray pawl is shorter than the chain of long spray pawl.Short spray The length of the hook box of pawl is shorter than the length of the hook box of long spray pawl.

1st, to guarantee drilling efficiency and ensureing drilling quality, using full-sleeve anchor cable rig, bit diameter is 150mm.Adopt Mud off pore-forming is used, mud pit pulping will be also excavated out in advance.Mud pit is excavated in strip along the anchor cable scope of operation, should not mistake Deep, drilling is finished to be transported outward serosity using slush pump, it is ensured that lower floor's earth excavation can be smoothed out.During drill hole of drilling machine, by anchor cable Drilling rod needed for design length will drill is put neatly, and drilling rod is finished, and hole depth is also just in place.

2nd, the setting-out work of hole position is carried out with total powerstation.Orifice center should be released according to design first, then according to design Angle extends to excavation slope surface.The fender pile of hole position should be drawn before drilling, in order to the rig rear determination hole heart in place.

3rd, anchor cable is worked out in scene while drilling, and grouted part adopts bellows-shaped, tensioning section to adopt rectilinear form. Anchor cable adopts 1860 grades of high strength steel strands.The cutting of steel strand wires should be carried out using cutting machine, can't be using electricity, gas welding cutting. The blanking place length of steel strand wires should be not less than the length of anchor cable.Steel strand wires straighten process should certain protective measure, prevent Steel strand wires are ejected and are hurted sb.'s feelings.

The cutting length of steel strand wires is：Anchor cable length+anchorage thickness+jack active length.According to setting when anchor cable is prefabricated Meter will seek number, and lower good high strength steel strand wraps up steel strand wires free segment, and the coating butter on steel strand wires free segment with sleeve pipe. To prevent slip casting rear slurry bonding free segment, so as to ensure freely extending for non-anchored section, casing length is equal to design free segment Length.Anchoring section carries out oil removal treatment, ensures the adhesion strength between steel strand wires and serosity.Anchor rope grouting is using using PE slip castings Pipe, point once grouting pipe and secondary grouting pipe, once grouting pipe are communicated to bottom（100～200mm is preferably away from bottom hole）, secondary grouting Grouting Pipe should make one meter of long floral tube in the range of anchoring section every two meters, and floral tube eyelet is φ 8mm, in order to serosity Dispersion, bottom of the tube tightened with iron wire, and tapping is wrapped up with adhesive tape in case once grouting serosity is entered.To ensure steel strand wires At hole position center, one localizer should be set every two meters.

Steel strand wires Grouting Pipe is integrally bundled into a branch of using localizer.Anchor cable should check anchor cable quality before laying, specification is long Degree, can be installed after meeting design requirement.To prevent steel strand wires end insertion hole wall, steel strand wires termination should be set before construction Put breast boards.

4th, to before anchor cable hole dress rope, whether with hole number consistent, after confirmation is errorless, then clear with high-pressure blast if will check anchor cable numbering Hole is once, you can install anchor cable.

5th, slip casting adopts special grouting pump, and the pressure gauge of grouting pump should be through checking, and reading can correctly reflect grouting pressure.

Serosity used by slip casting should be in strict accordance with match ratio Site.Serosity is with mix with forbidding to use standing time Long serosity.

First time normal pressure grouting, grouting pressure are 0.5Mpa.Slip casting quantity is measured using hole depth and calculates theoretical grouting amount Double control.Slip casting first is advisable less than 1 meter with closing anchoring section and invading freedom length.Using high-pressure blast dredging note after grouting Slurry pipe, it is ensured that not plugging during second slip casting.After first time grouting initial set 24h, secondary grouting can be carried out.The note of secondary grouting Slurry pressure is preferably 2.0Mpa.Aperture sets stop grouting plug, keeps pressure 5～8 minutes, using the slabbing action of high-pressure slip-casting, makes anchoring The diameter of body becomes big, increased the radial compressive stress in soil, while make anchoring body obtain coarse surface, so as to improve anchor pole with Cohesive force between the soil body, improves the bearing capacity of anchor cable.The situation that special messenger observes dewatering well should be arranged during slip casting, during first row slip casting also It should be noted that the situation of change on ground, should be stopped operation immediately if any abnormal conditions, ascertain the reason and take corresponding measure；

6th, after slip casting finishes 5～10 days, anchoring body intensity more than 15MPa be not less than design strength 75% when, can tensioning, Handling waist rail surface anchor cable aperture before tensioning first well makes which smooth, it is to avoid tension stress is concentrated, cushioning -300 × 300 × 16 Steel plate, carries out prestretching with the pulling force of 60kN.Design requirement tensile load will reach design pulling force, and lock load for design pulling force 75%, therefore at anchor head during tensioning, do not put locking plate, up to after design pulling force, off-load is to 0, then anchor head assigns locking plate for tensile load, Ability tensioning is to locking load.In stretching process, tensile load classification is carried out, and in every grade of loading grade observation time, is surveyed and is read anchor head Displacement should not be less than 3 times.When tensioning grade reaches design pulling force, kept for 15 minutes, and reading anchor head position is surveyed in observation time Move 3 times, survey every time and read shift value and be not more than 1mm and just calculate displacement to tend towards stability, otherwise continue to observe which and conjugate that tend towards stability can Continue the tensioning of anchor cable；

7th, after compensating tensioning, hole-sealing grouting is carried out immediately.For the anchor cable that has a down dip, Grouting Pipe is inserted from preformed hole, until the mouth of pipe enters To anchoring section top surface about 50cm；Air in hole is discharged via the exhaustor being located at positioning slurry-stop ring.After hole-sealing grouting, from anchor Tool amount rises and stays 500mm steel strand wires, and remaining part is clipped, and the cement mortar that thickness is coated outside which not less than 50mm is protected Layer.

Pit retaining monitoring

1st, basis《Architecture Foundation Pit Engineering Specifications of Monitoring Technology》（GB50497-2009）In requirement：The 1-3 from beyond margin of foundation pit Times excavation of foundation pit depth bounds domestic demand surrounding enviroment to be protected should be used as monitoring object.The foundation ditch is drafted by 3 times of excavation of foundation pit Monitoring object in depth bounds should be monitored.Foundation ditch and surrounding enviroment monitoring are combined with instrument monitoring using walkaround inspection Method carry out.

2nd, the site setup of monitoring point：Foundation pit enclosure wall（Side slope）The level on top should be arranged along foundation ditch periphery, in the middle part of periphery, Monitoring point is arranged at external corner.Monitoring point level interval is not more than 20m, and per side, monitoring is counted out no less than 3, and monitoring point is arranged on On enclosure wall top or foundation ditch slope top.Sloping timbering, 0.5～1m reinforcing bars to be squeezed in the soil body of side slope top, reinforcing bar top stays 10～ The 15cm coagulation soil stabilizations；Support pile supporting, squeezed at the top of Guan Liang with survey nail, monitoring mark is done with paint.

3rd, foundation pit enclosure wall（Side slope）Top horizontal displacement monitoring：Seen according to the situation of reconnaissance trip, side slope top, stake top level Displacement is monitored using method of polar coordinates.Method of polar coordinates is using the polar coordinate principle in mathematics, with two control point as coordinate Axle, sets up polar coordinate system as limit with one of point, determines observation station to the distance of limit, determine observation station and limit line With the method for the angle of two known point lines.

Method of polar coordinates is monitored method, as shown in figure 8,2 points of A, B is known point, C, C are unknown point：

When determining unknown point C coordinate, the azimuth angle alpha of known point A, B is first calculated_BA：

；Y_AFor the Y-axis coordinate of A points, Y_BFor the Y-axis coordinate of B points, X_AFor the X of A points Axial coordinate, X_BFor the X-axis coordinate of B points；

Measuring instrument determines angle beta and length of side BC, according to formulaCalculate BC azimuth angle alphas_BC；

Calculate C point coordinates：

4th, foundation pit enclosure wall（Side slope）Top vertical displacement observation：The Foundation Pit top vertical displacement monitoring is using levelling side Method is carried out, and measurement process is strictly pressed《Building deformation measurement specification》The requirement of two grades of level wire measurement techniques, comes and goes mis-tie misclosure 2.0mm requirements are should be less than, and formation is closed and observation route, the elevation of each observation station measured with precision level, can be obtained after being computed To sedimentation or the protuberance situation of change of monitoring object.

5th, cheat outer soil body deeply mixing cement-soil pile observation：

5.1 soil horizontal displacement points are laid

Soil body deep layer lateral displacement monitoring point is preferably arranged in the middle part of foundation ditch periphery, at external corner and representational position.Monitoring Point level interval is preferably 20m～50m, and per side, monitoring is counted out and should not be less than 1 depth according to excavation of foundation pit, the foundation ditch deep layer Horizontal displacement monitoring hole punching depth is 20m, is fathomed as 18m.

The monitoring of enclosure wall or soil body deeply mixing cement-soil pile is preferably using the pre-buried inclined tube in body of wall or the soil body, by inclinometer The method for observing each depth horizontal displacement.By 4m（Or 2m）70mm, the inclinometer pipe of a section of internal diameter 53mm are connected section by section with Shu Jie It is connected together, while checking whether exterior notch and inner tank mouths align, Guan Yuguan first coats PVC glue on the outside of inclinometer pipe when connecting Then inclinometer pipe is inserted Shu Jie by water, in beam section four direction self-tapping screw or aluminium rivet fastening Shu Jieyu inclinometer pipes.Every Individual beam section joint two ends are wrapped up with mackintosh, prevent cement mortar from penetrating in inclinometer pipe from joint.In inclinometer pipe spreading process In, constantly inclinometer pipe is put in advance in good hole, treats that adapter terminates, after inclinometer pipe placement in place, it is necessary to check inclinometer pipe Whether perpendicular to foundation ditch face, whether the upper and lower notch of inclinometer pipe reverses a pair of inside grooves.Only in the inclinometer pipe, groove location meets and requires After can backfill.

5.2 soil horizontal displacement method of testings

Inclinometer pipe should be in 3～5 days build-in tests 2～3 times before excavation. wait distinguishing that inclinometer pipe after steady statue, takes which and put down Average starts official testing work as initial value.Probe guide wheel is directed at into the notch consistent with measured displacement direction, is slowly put To ttom of pipe. probe stops a few minutes in ttom of pipe, after, display instrument stable reading basically identical with temperature in pipe of popping one's head in starts prison Survey.By the scale graduation on probe cable, average rate is lifted.Every 500mm readings once, and make a record.Treat that probe is promoted to At the mouth of pipe, 180 ° are rotated, then is measured as stated above once.Measurement result will average twice, to eliminate inclinometer itself Error.The horizontal displacement that each survey section is tested is linked to be into line along depth and just constitutes inclinometer pipe pattern curve.

Calculation procedure：

In formula：

The upper and lower guide wheel spacing of inclinometer；

Clinometer probe sensitive axes and gravity axis angle；

The horizontal departure amount of section is surveyed in starting（mm）；

Horizontal departure amounts of the measuring point n relative to starting point（mm）；

For inclinometer inclinometer tube orifice horizontal displacement（mm）.

During measurement, movable gauge head is put into people's inclinometer pipe, make the guide roller on gauge head be stuck in the guide groove of deviational survey inside pipe wall In, dynamic along trough roller, movable gauge head can continuously determine the horizontal displacement change along inclinometer pipe entire depth.

The operation principle of inclinometer is changed by the arc angle determined based on action of gravity on the basis of pendulum according to pendulum. When the soil body produces displacement, the inclinometer pipe in people's soil body is buried with soil body synchronous shift, the displacement of inclinometer pipe is the position of the soil body Shifting amount.

The movable gauge head being put in inclinometer pipe, the amount measured are the change of pitch angle Δs of inclinometer pipe on each different waypoint Xi, and the corresponding displacement increment Δ Si of this section of test tube is：

Δ Si=Li Sin Δ Xi

In formula, Li is the unit length between each section of point（Rice）.

When the depth enough that inclinometer pipe is buried, ttom of pipe may be considered displacement fixed point, and the horizontal displacement value Δ n of the mouth of pipe is just It is the summation of each segment displacement increment：。

6th, deep soil lateral displacement（Deviational survey）Observation：Soil body lateral displacement（Deviational survey）Observed from accurate inclinometer, surveyed Measure and tested in embedded inclinometer pipe.Its process is as follows：Instrument probe is put to test tube bottom along cross guide slot, from bottom to A numerical value is surveyed on top per 0.5m；The accumulative of the difference that measured value is compared with initial value in Excavation Process is to be caused due to excavation Displacement（Imbed motionless layer in test tube bottom, it is believed that ttom of pipe is motionless）.

7th, cheat outer water table measure：Unscrew screw behind water-level gauge wire spool, after making wire spool rotatably mounted, press electricity Source button, is put into water level pipe gauge head, handles steel ruler cable, allows gauge head slowly to move down, when gauge head contact is to the water surface When, receiving system and will send short buzzer, now read reading of the steel ruler cable at the mouth of pipe, i.e., in water level pipe, the water surface is extremely The distance of the mouth of pipe.Then the absolute elevation of the water level pipe mouth of pipe is measured with NA2 precision levels using the method for the measurement of the level, is passed through It is calculated the absolute elevation of the water surface in water level pipe.

Measuring accuracy is：1mm.

Calculation procedure：

In above-mentioned formula：

D_SWater surface absolute elevation in-water level pipe（m）；

H_S- water level pipe mouth of pipe absolute elevation（m）；

The distance of the water surface and the mouth of pipe in-water level pipe（m）；

- i ＆ lt water level absolute elevation（m）；

- the i-th -1 water level absolute elevation（m）；

The initial absolute elevation of-water level（m）；

- this water-head（m）；

- accumulative water-head（m）.

8th, anchor cable Internal Force Monitoring：The Internal Force Monitoring point of anchor cable should be selected stress is larger and representational position, foundation ditch Per in the middle part of side, at external corner and the section of complex geologic conditions preferably arranges monitoring point.The Internal Force Monitoring point quantity of every layer of anchor cable should be The 1～3% of this layer of anchor pole sum, not should be less than 3.Each layer monitoring location is preferably consistent on vertical.On the every body of rod Test point be preferably arranged on anchor head nearby and the representational position of stress.

In 8.1 anchor cables, force is embedded

Install before anchor cable carries out tensioning.

To ensure there is enough rigidity between anchor dynamometer and body of wall stress surface, after making anchor cable stress, stress surface position is not Cause distorting sag.

8.2 measuring instrument

Anchor dynamometer, JTM-V10B digital display frequency readings instrument.

Force measuring method in 8.3 anchor cables：The measurement of initial value is carried out before anchor cable stress, the measured value monitored twice calculates which Average, as reference value.

It is monitored by the frequency of design and code requirement during bearing load.During monitoring, recorded data is Frequency values, according to Calibration of measuring equipment constant, calculate anchor cable value of thrust；

Anchor cable pulling force computing formula is：Ten B of P=K △ F

In formula：P anchor cables load value (KN)

K measuring instrument calibration coefficients (KN/F)

Variable quantity (F) of the △ F output frequency modulus real-time measurement values relative to reference value

The calculating correction value (KN) of B measuring instruments.

Claims (8)

1. narrow and small place deep pit digging construction method for supporting, the foundation depth：12.1m；Groundwater depth in foundation ditch：30m； The outer groundwater depth of foundation ditch：30m；Supporting construction important coefficient：1.0；Soil nailing partial safety factor for load 1.25；Pulling capacity of soil nail safety Property coefficient：1.6；Whole slide temperature safety coefficient：1.3；6.1 m of slope line floor projection；12.1 m of slope line upright projection；Slope line 63 degree of inclination angle；It is characterized in that including the description below：

（1）Foundation pit stope support is carried out using " soil nailing+spray anchor " method；

（2）" support pile+anchor cable " method is taken to be transported through station, gallery without the supporting of slope space；

（3）Pattern foundation pit supporting structure is carried out using " support pile+anchor cable " method；

First carry out support pile to set before excavation of foundation pit, be respectively provided with the support pile of three types:A type stakes, the long 32.2m of stake, stake footpath 1m, pile spacing 1.5m；Type B stake, the long 22.5m of stake, stake footpath 0.8m, pile spacing 1.2m；B type stakes, the long 15.1m of stake, stake footpath 0.8m, stake Spacing 1.2m；One is arranged in each stake top and encloses Guan Liang, wherein, A type stakes are arranged in foundation ditch periphery of the cutting depth more than 17m, Away from 1.5m；Type B stake is arranged in the foundation ditch periphery of cutting depth 10-17m, spacing 1.2m；B type stakes are arranged in cutting depth 8-10m Foundation ditch periphery, spacing 1.2m.

2. narrow and small place deep pit digging construction method for supporting according to claim 1, is characterized in that " soil nailing+spray anchor " Method includes the description below：

（1）Soil nailing is prefabricated；The soil nailing is the reinforcing bar of 22mm and medium-height trestle is constituted that by diameter reinforcing bar length direction is at interval of 2m It is provided with a pair pairs of medium-height trestles；It is described to include stake body to medium-height trestle, there is soil nailing draw-in groove along its length on stake body, The section semicircular in shape of soil nailing draw-in groove;Respectively there is a colligation groove at the two ends of stake body, also have three spacing legs on stake body；Limit The edge of position leg is curved, and the summit of three spacing leg curved edges is located on same circumference；

The spacing leg of two of which is located on straight line, and another spacing leg is vertical with the two spacing legs；

（2）Hole-sealing grouting after soil nailing pore-forming, grouting mode are bottom slip casting, and serosity started to aperture from bottom hole by slip casting pore Filling is filled out；When serosity is filled to aperture from bottom, also need to carry out at least 2 times pressurizations, pressure is 0.3Mpa, it is ensured that serosity is crowded with Hole wall, the fullness coefficient that serosity is injected into hole are more than 1；

（3）It is the reinforced mesh of the squared mesh of 150mm into spacing using the reinforcing bar colligation that diameter is 10mm, is laid in slopes Surface, arranges the reinforcing bar reinforcing mat that some stiffeners are constituted above reinforced mesh, the mesh of reinforcing bar reinforcing mat assumes diamond in shape, reinforcing bar The reinforcing bar cross point of reinforcing mat is located at soil nailing position, and stiffener is welded as a whole with soil nailing L-shaped hook, forms overall anchoring Structure；

（4）Using air compressor machine by concrete ejection in domatic, shower nozzle is not more than 80cm, layering injection, Concrete Thick apart from domatic Degree is not less than 10cm.

3. narrow and small place deep pit digging construction method for supporting according to claim 1, is characterized in that " the support pile+anchor Rope " method includes the description below：

（1）Anchor cable is prefabricated；The anchor cable is a branch of steel strand wires, and anchor cable one end is embedded in deep soil in advance by pore-forming slip casting, another End connection locking device, applies a prestressing force in steel strand wires by tensioning, and steel strand wires act on backing plate, waist rail by rigging, Waist rail acts on support pile, it is ensured that support pile when by soil body horizontal peristaltic forces is not subjected to displacement and destroys；

（2）First time normal pressure grouting is carried out after anchor cable pore-forming, grouting pressure is 0.5Mpa；Grouting quantity is closing anchoring section and intrusion Freedom length is less than 1 meter；Grouting initial set 24h for the first time is treated, secondary grouting is carried out；The grouting pressure of secondary grouting is 2.0Mpa, keeps pressure 5～8 minutes；

（3）Anchor cable length is respectively 22m anchor cables, and 25m anchor cables, 30m anchor cables, the stake of A types adopt 4 row's 30m cable boltings, anchor cable horizontal Spacing 1.5m, with an anchor cable, level interval 3.5m, first floor anchor cable is apart from 2.8m at the top of foundation ditch for the stake of an A type；Type B stake adopts 3 Row's 25m cable boltings, anchor cable horizontal spacing 2.4m is two Type B stakes with an anchor cable, level interval 3m, first floor anchor cable distance 3.5m at the top of foundation ditch；The stake of b types adopts 2 row's 22m cable boltings, anchor cable horizontal spacing 2.4m to be that an anchor cable is matched somebody with somebody in two b types stakes, erect To spacing 3m, first floor anchor cable is apart from 3.5m at the top of foundation ditch；

（4）Waist rail is installed：Waist rail is made using being welded with connecting plate in the middle of two I-steel, and anchor cable is from the middle of two I-steel Gap passes through；

（5）Anchorage cable stretching：Slip casting is finished 5～10 days, when anchoring body intensity is not less than the 75% of design strength more than 15MPa, is entered Row tensioning.

4. the narrow and small place deep pit digging construction method for supporting according to claim 1 or 3, is characterized in that the anchor cable, bag Include push rod, churning drilling rod, single direction thrust ball bearing, bearing block, axial nozzle, radial nozzles and tungsten bur；The push rod is One multidiameter, is provided with the push rod axial passage of insertion in multidiameter；The big end bore design of multidiameter has trapezoidal thread, multidiameter The external screw thread for the axle journal with single direction thrust ball bearing inner hole being respectively arranged with small end is cylindrical and being coordinated with churning drilling rod；It is single Be engaged to thrust ball bearing inner ring with the axle journal of push rod, the inner hole of outer ring and bearing block；Push rod installs bearing and bearing It is connected with churning drilling rod after seat again；Churning drilling rod is shaft-like structure, and the churning drilling rod of eccentric insertion is offered inside churning drilling rod Axial passage, one end bore design of churning drilling rod have female thread to match, make both be connected with the external screw thread of push rod, push rod Axial passage and churning drilling rod axial passage connect；The other end of churning drilling rod is designed to linear side on double inclined plane, double inclined plane Formula is disposed with multiple tungsten burs, and the nearly bibeveled end external cylindrical surface of churning drilling rod offers upper groove and recessed up and down respectively Groove, churning drilling rod axial passage are higher by the bottom land of upper groove, and upper groove axial end is equipped with connecting with churning drilling rod axial passage Axial nozzle, low groove bottom land is provided with the radial passage being connected with churning drilling rod axial passage, fills on the end face of radial passage There are radial nozzles；Radial direction gyration aperture is left between inner hole of bearing seat and push rod are cylindrical, between bearing block end face and push rod step end face Leave axial gap；It is provided with push rod is cylindrical and is connected the symmetrical flat face for installing clamping with borer drill rod for push rod.

5. narrow and small place deep pit digging construction method for supporting according to claim 1, is characterized in that per layer of shoveling is less than 2m, first digs out the nail Construction scope of operation, and nail Construction is finished, and reaches some strength, then carries out large area excavation, last layer Shield reaches intensity, just carries out next layer of excavation.

6. narrow and small place deep pit digging construction method for supporting according to claim 1, after the completion of it is characterized in that pattern foundation pit supporting structure Excavation slope horizontal displacement monitoring is carried out using method of polar coordinates；According to formulaCalculate known The azimuth angle alpha of 2 points of A, B_BA, Y_AFor the Y-axis coordinate of A points, Y_BFor the Y-axis coordinate of B points, X_AFor the X-axis coordinate of A points, X_BFor B points X-axis coordinate；

When determining unknown point C coordinate, the azimuth of known point A, B is first calculated：

；

Angle beta and length of side BC are determined, according to formulaCalculate BC azimuth angle alphas_BC；

Calculate C point coordinates：

。

7. narrow and small place deep pit digging construction method for supporting according to claim 1, after the completion of it is characterized in that pattern foundation pit supporting structure Soil horizontal displacement change △ X are carried out using inclinometer：

In formula：

The upper and lower guide wheel spacing of inclinometer；

Clinometer probe sensitive axes and gravity axis angle；

The horizontal departure amount of section is surveyed in starting（mm）；

Horizontal departure amounts of the measuring point n relative to starting point（mm）；

For inclinometer inclinometer tube orifice horizontal displacement（mm）.

8. narrow and small place deep pit digging construction method for supporting according to claim 1, after the completion of it is characterized in that pattern foundation pit supporting structure Calculate anchor cable pulling force：

Ten B of P=K △ F

In formula：P anchor cables load value (KN)；

K measuring instrument calibration coefficients (KN/F)；

Variable quantity (F) of the △ F real-time measurement values relative to reference value；

The calculating correction value (KN) of B measuring instruments；

Reference value carries out initial value measurement twice before anchor cable stress, twice the meansigma methodss of initial value.