CN204982908U - Elevartor shaft deep basal pit seepage prevention structure - Google Patents

Abstract

The utility model discloses an elevartor shaft deep basal pit seepage prevention structure relates to secret concrete structure construction technical field. The utility model discloses the bottom from bottom to up of deep basal pit is rubble water conservancy diversion layer, concrete cushion, coating mortar in proper order, and deep basal pit lateral wall is all around stood by as an outsider and inwards is coating mortar, brick fetal membrane in proper order, and it is native that foundation ditch limit original state is hugged closely to the brick fetal membrane, the concrete cushion be two bed courses, including underlayer and last bed course, completely spread the water barrier between underlayer and last bed course, the water barrier upwards extends certain length along brick fetal membrane outer wall all around. The utility model discloses can be under construction lateral wall and bottom to the deep basal pit and realize seamlessly blocking water closedly, effectively block infiltration of deep basal pit bottom and the problem of getting damp, create the dry scope of operation for foundation ditch waterproofing.

Description

Elevator shaft deep foundation ditch leakage preventing structure

Technical field

The utility model relates to underground concrete structure technical field of construction, specifically a kind of elevator shaft deep foundation ditch leakage preventing structure.

Background technology

Answer high residential building to the growth requirement of the underground space, make elevator shaft place cutting depth larger, normal conditions, only take periphery to build brick fetal membrane, substrate concreting bed course by laying bricks or stones before elevator shaft deep foundation ditch waterproof, arrange dewatering well manually the timing measure of drawing water reach " resistance, draining " object.But often due to the impact of underground high water level, cause soil mass of foundation pit displacement in various degree, cause elevator foundation pit brick fetal membrane, by soil body extruding force, a certain amount of deformation occurs, thus cause elevator shaft to build the generation in brick fetal membrane crack by laying bricks or stones, and then the situation of Groundwater infiltration elevator foundation pit brick fetal membrane inside.If when construction plant water-stop curtain closes, heavy caliber well point needs continual dewatering operation, groundwater table in overall reduction construction plant, when this work long hours is uninterruptedly constructed, reduce foundation pit of elevator shaft bottom water level until lower than absolute altitude at the bottom of foundation ditch, because the duration is longer, many adverse effects certainly will be produced to elevator shaft next procedure time started and construction quality.If construction plant water-stop curtain does not close, easily there is the phenomenon repeatedly that fluctuates up and down in groundwater table, thus cause elevator foundation pit fetal membrane sidewall brickwork joint and substrate bed course percolating water constant, when cannot ensure the inwall drying of brick fetal membrane, larger difficulty is brought to this position waterproof construction, buries certain hidden danger with regard to waterproof quality simultaneously.

Utility model content

Technical problem to be solved in the utility model is to provide a kind of elevator shaft deep foundation ditch leakage preventing structure, can to deep foundation pit construction sidewall and bottom realize seamless block water closed, infiltration and problem of getting damp bottom effective blocking-up deep foundation ditch, for foundation ditch waterproof construction creates drying operation face.

For solving the problems of the technologies described above; technical solution adopted in the utility model is: a kind of elevator shaft deep foundation ditch leakage preventing structure; the bottom of deep foundation ditch is followed successively by rubble guide layer, concrete cushion, cement mortar protective course from bottom to top; the sidewall of deep foundation ditch surrounding is from being followed successively by cement mortar protective course, brick fetal membrane outside to inside; brick fetal membrane is close to foundation ditch limit undisturbed soil; described concrete cushion is two bed courses; comprise underlayer and upper bed course; between underlayer and upper bed course, completely spread water barrier, water barrier surrounding upwards extends certain length along brick fetal membrane outer wall.

Further technical scheme, is cast with Concrete Anti water layer between brick fetal membrane and foundation ditch limit undisturbed soil, and described Concrete Anti water layer is connected with concrete cushion and is integrated.

Further technical scheme, the thickness of described Concrete Anti water layer is 100mm, and flushes with the height of brick fetal membrane.

Further technical scheme, the length that water barrier upwards extends is 300mm-500mm.

Further technical scheme, the thickness of described underlayer and upper bed course is 50mm-60mm.

Further technical scheme, is equipped with waterproofing course between rubble guide layer and concrete cushion.

Further technical scheme, described water barrier and waterproofing course are malthoid or Polypropylence Sheet.

Further technical scheme, the cement mortar protective course linking of the cement mortar protective course bottom deep foundation ditch and surrounding sidewall is integrated.

Further technical scheme, between cement mortar protective course and brick fetal membrane, and is equipped with SBS high-polymer modified pitch coiled material between concrete cushion and cement mortar protective course.

Further technical scheme; dewatering well has been dug in deep foundation ditch; dewatering well periphery is provided with cushion cap; cushion cap is on cement mortar protective course; fill up concrete outside cushion cap and form elevator shaft base plate, be provided with self priming pump in dewatering well, the switch of self priming pump is connected with time switch; precipitation well head is provided with steel deck-plate, and on steel deck-plate, shutoff has concrete shutoff.

The beneficial effect adopting technique scheme to produce is: the leakage preventing structure of the utility model elevator shaft deep foundation ditch, specifically elevator shaft fetal membrane construction, change tradition and build merely the way that brick fetal membrane carries out deep foundation ditch construction of waterproof layer by laying bricks or stones, be converted to " double water-resistance "+combination the membrane type of " uninterruptedly hydrophobic ".Wherein, block water that membrane type is built by laying bricks or stones by the brick fetal membrane of routine, in the middle part of the two bed course of substrate 120mm sandwiched impermeable water proof material and on turn over to brick fetal membrane lateral wall 300mm-500mm that high peripheral one week Concrete Anti water layer forms the closed Water blocking system of sidewall and substrate with brick fetal membrane; Uninterrupted hydrophobic structure is combined by substrate rubble guide layer, foundation ditch periphery dewatering well, self-priming water pump, time switch, by blocking water, the structure that is combined into of hydrophobic two kinds of waterproof guards complements each other, co-operation, thorough change in the past common brick fetal membrane is seeped water along fetal membrane sidewall brickwork joint in deep foundation pit construction, by the Moisture Regain that water pressure at the bottom of the foundation causes greatly, for foundation ditch waterproof construction creates drying operation face.

Accompanying drawing explanation

Fig. 1 is the structural representation of the utility model embodiment;

Fig. 2 is the sectional drawing of in Fig. 1 I-I;

In figure: 1, Concrete Anti water layer; 2, brick fetal membrane; 3, foundation ditch limit undisturbed soil; 4, water barrier; 5, rubble guide layer; 6, elevator shaft base plate and cushion cap foundation; 7, bituminous seal cream; 8, dewatering well; 9, self priming pump; 10, non-fine concrete downcomer; 11, cushion cap; 12, steel deck-plate; 13, precipitation steel pipe; 14, concrete shutoff; 15, cement mortar protective course; 16, concrete cushion.

Detailed description of the invention

The utility model changes tradition and builds merely the way that brick fetal membrane carries out deep foundation ditch construction of waterproof layer by laying bricks or stones, is converted to double water-resistance and adds uninterruptedly hydrophobic combination membrane type.Wherein block water that membrane type is built by laying bricks or stones by normal brick fetal membrane, in the middle part of the two bed course of substrate 120mm the impermeable water proof material of sandwiched as Polypropylence Sheet, malthoid etc. and on turn over to brick fetal membrane lateral wall 300mm-500mm, form the closed Water blocking system of sidewall and substrate with the brick fetal membrane C20 pea gravel concreten waterproofing course 1 of peripheral a week.Hydrophobic structure is also that time control switch combination forms by substrate rubble guide layer 5, foundation ditch periphery dewatering well, self-priming water pump, time switch, by blocking water, the structure that is combined into of hydrophobic two kinds of waterproof guards complements each other, co-operation, thorough change in the past common brick fetal membrane is seeped water along fetal membrane sidewall brickwork joint in deep foundation pit construction, by the Moisture Regain that water pressure at the bottom of the foundation causes greatly, for foundation ditch waterproof construction creates drying operation face.

The utility model is simple to operate, continue precipitation, Be very effective, realizes the 100% dry of substrate and sidewall before the elevator deep foundation ditch waterproof construction of high water level area.In the whole foundation pit construction stage, average every hole dewatering well is saved artificial pumping and is taken about 1.5 ten thousand yuan.

Key technology feature of the present utility model: 1, one of double water-resistance structure is implemented in two steps by base concrete bed course 16 in traditional construction, middle sandwiched water proof material as impermeable in Polypropylence Sheet, malthoid etc., effectively blocks infiltration and problem of getting damp bottom deep foundation ditch; 2, two of double water-resistance structure is outside deep foundation ditch brick fetal membrane, build the thick Concrete Anti water layer 1 of 100mm, and is built by the 300mm-500mm that institute's sandwiched water proof material in two for substrate bed course turns in wherein, achieve foundation pit side-wall and bottom seamless block water closed.

Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail.

Shown in Fig. 1, Fig. 2, the bottom of deep foundation ditch is followed successively by rubble guide layer 5, concrete cushion 16, cement mortar protective course 15 from bottom to top, the sidewall of deep foundation ditch surrounding is from being followed successively by cement mortar protective course 15, brick fetal membrane 2 outside to inside, brick fetal membrane 2 is close to foundation ditch limit undisturbed soil 3, described concrete cushion 16 is two bed courses, comprise underlayer and upper bed course, between underlayer and upper bed course, completely spread water barrier 4, water barrier 4 surrounding upwards extends certain length along brick fetal membrane 2 outer wall; The length that water barrier 4 upwards extends is 300mm-500mm; The thickness of described underlayer and upper bed course is 50mm-60mm.

Between brick fetal membrane 2 and foundation ditch limit undisturbed soil 3, be cast with Concrete Anti water layer 1, described Concrete Anti water layer 1 is connected with concrete cushion 16 and is integrated, and wherein, the thickness of Concrete Anti water layer 1 is 100mm, and flushes with the height of brick fetal membrane 2.

Waterproofing course is equipped with between rubble guide layer 5 and concrete cushion 16.Described water barrier 4 and waterproofing course are malthoid or Polypropylence Sheet.

Cement mortar protective course 15 bottom deep foundation ditch and the cement mortar protective course 15 of surrounding sidewall are integrated.Between cement mortar protective course 15 and brick fetal membrane 2, and between concrete cushion 16 and cement mortar protective course 15, be equipped with SBS high-polymer modified pitch coiled material.

Dewatering well 8 has been dug in deep foundation ditch; dewatering well 8 periphery is provided with cushion cap 11; cushion cap 11 is on cement mortar protective course 15; fill up concrete outside cushion cap 11 and form elevator shaft base plate; self priming pump 9 is provided with in dewatering well 8; the switch of self priming pump 9 is connected with time switch, and precipitation well head is provided with steel deck-plate 12, and on steel deck-plate 12, shutoff has concrete shutoff 14.

Construction technology process of the present utility model is as follows:

One, technology planning, containing preparation of construction

1, Data acquisition, arranges

Survey report, around adjacent building file data, building operations handbook and this engineering drawing with checking this construction plant, grasp construction plant geology, water wave basic condition, understand annual water level float value, respectively clear and definite water level bound timing node.Each data gathers formulates corresponding dewatering measure afterwards according to geological condition, height of water level, and the node organization fluting simultaneously as far as possible avoiding water level high is broken ground.The every reference index of adequate preparation, avoids unfavorable factor of constructing, for maximum ideal operation face is created in construction;

2, place is made an on-the-spot survey

According to the parameters index that data collection draws, make an on-the-spot survey on the spot to scene.For on-site actual situations, amendment technology measure, must ensure that planning and on-the-spot truth are unified and coordinate, objectively respond authenticity, in real time dynamic effect, avoid the delayed of information or imperfection, in order to avoid impact judges, guides planning mistaken ideas;

3, the determining of program planning

Gather the truth of conclusion and the reconnaissance trip drawn according to Data acquisition, grasp actual water level and soil property situation, the technology planning of amendment establishment in early stage, require that planning must guide field construction.

Two, foundation pit of elevator shaft excavation

1, confide a technological secret

Carry out elevator foundation pit technical annotation in construction to workman, organize study, grasp soil excavation basic demand, avoid the collision with main building castinplace pile in work progress, lose in order to avoid castinplace pile is stressed, destroy its construct validity.Must ensure that in Excavation Process, forming quality is high, the soil body does not cave in, in order to avoid affect follow-up fetal membrane building construction.Indwelling sump bottom foundation ditch, guarantees that open fire is discharged in time;

2, surveying setting-out

Surveyor identifies elevator foundation pit according to main building control point need excavate boundary line, and puts ratio arm boundary line, slope.Excavation absolute altitude is checked in real time, in order to avoid backbreak in digging process;

3, excavation quality controls

The disposable digging depth of strict control, avoids soil body local buckling to cave in, affects Forming Quality.According to the requirement of construction technology planning scheme, controlling absolute altitude at the bottom of excavation of foundation pit, lower than elevator shaft drawing absolute altitude about 250mm, is the ready work of follow-up laying rubble guide layer, forms gradient ratio simultaneously, be convenient to open fire and collect in the middle of four circumferences.

Three, broken stone cushion layer and rubble guide layer are laid and precipitation steel pipe 13 is installed

1, the thick broken stone cushion layer of 250mm is completely spread in foundation ditch; require ballast grain sizes 25-40mm; guarantee that foundation ditch bottom water can come together in foundation ditch central authorities concave part through rubble gap; precipitation steel pipe 13 is embedded in foundation ditch central authorities recessed location simultaneously; guarantee that steel pipe is imbedded the following degree of depth of rubble and is not less than 500mm; steel pipe bottom and rubble joint, in order to avoid soil layer mud is the shutoff of dewatering well end opening, affect dewatering effect simultaneously.After broken stone cushion layer is smooth, the isolation that view picture malthoid carries out blinding concrete and macadam is laid on top, can first build underlayer 50mm;

2, the installation of self priming pump and longitude and latitude time switch

Self priming pump puts collector well pipe inside, and namely non-fine concrete is by water pipe, guarantees that pump housing suction valve contacts with recess water down.Self priming pump switch and longitude and latitude time switch are in series by electrician, carry out setting to time switch simultaneously, and ensure that self priming pump is every automatic operation half an hour, to reach without open fire in dewatering well, and self priming pump is without the situation of running no load.The idling loss of self priming pump is it also avoid while keeping continuing precipitation.

Four, concrete cushion construction

Concrete cushion construction is divided into upper and lower two-layer, construct respectively, first on the malthoid layer on broken stone cushion layer top, build the concrete of 50mm, i.e. underlayer, after its surperficial initial set, view picture Polypropylence Sheet is set on top, and it is long to reserve each 300mm of flange in surrounding, closing for brick fetal membrane circumferential concrete waterproof, then carries out upper bed course 50mm concreting;

To the ash bucket handling of pea gravel concreten be filled to blanking in elevator foundation pit by tower crane, blanking process is evenly slow, blanking is highly unsuitable too high too fast, in order to avoid cause concrete disintegration, affect concrete structural strength, avoid concrete to the blastic deformation of broken stone cushion layer upper plastic cloth or malthoid, even because blanking is too fast, stone scratches the situation of Polypropylence Sheet or malthoid simultaneously.Concrete evenly shakeouts by workman, with 2m aluminium alloys darby by levelling for foundation ditch bed course, receives face, carries out concrete maintenance work simultaneously.

Five, brick fetal membrane is built by laying bricks or stones

1, absolute altitude and angular coordinate are checked

Project survey person utilizes pilot measurement absolute altitude reference point to carry out inspection with regard to bed course absolute altitude and checks, after errorless, pilot measurement goes out each angular coordinate of elevator foundation pit, according to position fixing snap the line process respectively, eject construction control boundary line, guarantee that brick fetal membrane is built sectional dimension by laying bricks or stones and met Design Requirement Drawing;

2, masonry quality controls

Elevator brick fetal membrane is built each corner point by laying bricks or stones and is arranged marked rod, and inside brick fetal membrane building wall, hang logical line, ensures masonry quality;

In view of elevator foundation pit interior moisture content is comparatively large, cement mortar is long for time of setting, requires that every day, building wall height was no more than 1.5m, prevents that brick fetal membrane body of wall is disposable builds too high buckling deformation by laying bricks or stones.Strictly control masonry quality in building wall process, guarantee that 31 build by laying bricks or stones, namely one block of brick, shovel ash, squeeze and rub, guarantee mortar is full, the even 8-12mm of mortar joint, stops baste, blind seam, straight joint, jointing in time after construction, guarantees that mortar is evenly enriched in each gap, blocks all penetrating passages.By the inspect by instrument such as guiding ruler, plumb aligner wall leveling degree, verticality, strict control building construction quality.

Six, outside brick fetal membrane, Concrete Anti water layer is built

1, front preparation is built

Reserve when base concrete bed course is built Polypropylence Sheet that outside elevator shaft brick fetal membrane, each limit 300mm is long turns over and be close to fetal membrane body of wall, and fix with iron nail and body of wall, ensure that Polypropylence Sheet is formed and turn over the closed state that blocks water;

2, concreting

Outside brick fetal membrane, surrounding builds the thick concrete of 100mm, and height is same with brick fetal membrane.When building to 200mm height, the outside of Polypropylence Sheet is outwards overturn, and the smooth concrete thickness be paved with in building.Must guarantee in concreting process that layering is evenly built, stop fetal membrane side primary concreting to top, prevent lower side pressure uneven cause brick fetal membrane extrude cause crack, affect its whole structural stability.Carry out concrete vibrating work simultaneously, guarantee not leak shake, Bu Guozhen, ensure good construction quality, make sidewall concrete and foundation pad form an airtight entirety, play consolidated structures, resistance effect.

Seven, brick fetal membrane inner wall construction

1, plastering on inner walls process

Mortar requirement

Fetal membrane inwall adopts 1:2.5 to add the cement mortar of waterproof agent and smears thickness 10mm and levelling, utilizes the testing tools such as guiding ruler to check construction quality, guarantees that the face of plastering is smooth straight, avoid uneven, to construct hollowing in order to avoid affect later stage SBS asphalt water-proof coiled material;

2, special parts treatment

The small arc-shaped or 45 ° of slope angles that radius is 20mm must be made in brick fetal membrane corner, other negative and positive angles, position, facade interior angle and exterior angle;

3, waterproof matrix process

1), 1:2 cement mortar is smeared for the irregular position of bed course and carry out leveling;

2), the mortar pimple of substrate surface, thrust are rooted out, and surface dust, foreign material etc. cleaned out;

3), substrate surface should be solid, smooth, bright and clean, and the arc angle of flat smooth must be smeared in all yin, yang angles; Substrate surface should without the mass defect such as sand return, peeling, if there is the seriously defect such as coarse, uneven, must pick chipping whole after, fill by 1:2 cement mortar;

4), construction front broom and high pressure air blowing machine cooperation substrate surface dust is blown off, substrate surface must not have the phenomenons such as hollowing, cracking and dusting.

5) basic unit must be dry, and moisture content must not be greater than 9%.On-the-spot test method: put one block of coiled material or glass in substrate surface, sees with or without the globule below its basic unit for 3-5 hour later, as substantially anhydrous pearl can be constructed.

6) basic unit has to pass through management examination, and carries out hidden inspection record;

7) basic unit is dry and after cleaning out, brush supporting base treatment agent.Before brushing, first that base treatment agent mix is even, then with long round brush brushing, negative and positive angle and corner are painted and are brushed brush, to ensure the oil brushing of the cold end evenly, the brushing of thin portion puts in place, must not have and leak brush phenomenon.

4, waterproof construction

Brick fetal membrane inwall waterproof adopts SBS high-polymer modified pitch coiled material to carry out waterproofing work, and specific requirement is as follows.

1), the construction of SBS high-polymer modified pitch coiled material time, in fabric width, the heating of coiled material basal surface should be even, must not excessive heat or burn coiled material;

2), compacting should be flattened, coiled material and must bond closely between basal plane and each layer coiled material during paving;

3), paving side wall surface coil waterproof layer time, the measure preventing coiled material from gliding should be taked;

4), the lap width on two width coiled material minor faces and long limit all should not be less than 100mm;

5), coiled material seam must be pasted and be obturaged.The compatible encapsulant of seam mouth application wood property is obturaged, and width should not be less than 10mm;

6), in the corner of facade and plane, the seam of coiled material should be stayed in the plane, should not be less than 600mm apart from facade;

7), negative and positive angle place should do one deck additional waterproof course, and extra play width is 500mm, each 250mm in every limit, negative and positive angle, and snap the line puts coiled material well, and extra play is firm pasting in order, and lap width is 100mm, and exterior wall corner must smear into small round corner with negative and positive angle place.

5, pile crown and downcomer and the waterproofing work measure of layer contacts position:

1) first according to stake footpath or downcomer pipe diameter D, take then D+200mm as the length of side, cut out coiled material for square, the heart is that diameter draws circle with D-5mm in the square, circumferentially cuts on limit with scissors;

2) be starting point from square middle part on one side, cut off to circular outer diameter.At the square coiled material cut out and pipe root position, extra play coiled material cover is bonded at root of pipeline, is close on tube wall and metope, paste necessary tight compacting, not hollowing;

3) cut the wide fritter coiled material of 200mm and mend clip;

4) main water barrier twice are pasted;

5) coiled material is cut out a block length is square does defensive wall, length is pipe range D × 3.14+40mm, and width is 120mm, is evenly cut into osculum from long side direction, cuts out size and equals 1/2nd height;

6) by coiled material defensive wall and pipe root brushing binding material respectively, by coiled material defensive wall around pipe root firm pasting, then binding material edge sealing is used;

6, cement mortar protective course construction.

The utility model is specially adapted to the process construction of elevator deep foundation ditch waterproof homework face, high water level area, change tradition to build merely the way that brick fetal membrane carries out deep foundation ditch construction of waterproof layer by laying bricks or stones specifically, its membrane type that blocks water is built by laying bricks or stones by normal brick fetal membrane, sandwiched impermeable water proof material in the middle part of the two bed course of substrate 120mm and on to turn over to brick fetal membrane lateral wall 300mm-500mm and brick fetal membrane periphery the closed Water blocking system that one week C20 microlith waterproof concrete forms sidewall and substrate, thorough change in the past common brick fetal membrane is seeped water along fetal membrane sidewall brickwork joint in deep foundation pit construction, by the Moisture Regain that water pressure at the bottom of the foundation causes greatly, for foundation ditch waterproof construction creates drying operation face.

Claims (10)

1. an elevator shaft deep foundation ditch leakage preventing structure, the bottom of deep foundation ditch is followed successively by rubble guide layer (5) from bottom to top, concrete cushion (16), cement mortar protective course (15), the sidewall of deep foundation ditch surrounding is from being followed successively by cement mortar protective course (15) outside to inside, brick fetal membrane (2), brick fetal membrane (2) is close to foundation ditch limit undisturbed soil (3), it is characterized in that, described concrete cushion (16) is two bed courses, comprise underlayer and upper bed course, water barrier (4) is completely spread between underlayer and upper bed course, water barrier (4) surrounding upwards extends certain length along brick fetal membrane (2) outer wall.

2. elevator shaft deep foundation ditch leakage preventing structure according to claim 1, it is characterized in that, between brick fetal membrane (2) and foundation ditch limit undisturbed soil (3), be cast with Concrete Anti water layer (1), described Concrete Anti water layer (1) is connected with concrete cushion (16) and is integrated.

3. elevator shaft deep foundation ditch leakage preventing structure according to claim 1 and 2, is characterized in that, the thickness of described Concrete Anti water layer (1) is 100mm, and flushes with the height of brick fetal membrane (2).

4. elevator shaft deep foundation ditch leakage preventing structure according to claim 3, is characterized in that, the length that water barrier (4) upwards extends is 300mm-500mm.

5. elevator shaft deep foundation ditch leakage preventing structure according to claim 1, it is characterized in that, the thickness of described underlayer and upper bed course is 50mm-60mm.

6. elevator shaft deep foundation ditch leakage preventing structure according to claim 1, is characterized in that, between rubble guide layer (5) and concrete cushion (16), be equipped with waterproofing course.

7. elevator shaft deep foundation ditch leakage preventing structure according to claim 6, is characterized in that, described water barrier (4) and waterproofing course are malthoid or Polypropylence Sheet.

8. elevator shaft deep foundation ditch leakage preventing structure according to claim 1, is characterized in that, cement mortar protective course (15) linking of the cement mortar protective course (15) bottom deep foundation ditch and surrounding sidewall is integrated.

9. elevator shaft deep foundation ditch leakage preventing structure according to claim 1; it is characterized in that; between cement mortar protective course (15) and brick fetal membrane (2), and be equipped with SBS high-polymer modified pitch coiled material between concrete cushion (16) and cement mortar protective course (15).

10. elevator shaft deep foundation ditch leakage preventing structure according to claim 1; it is characterized in that; dewatering well (8) has been dug in deep foundation ditch; dewatering well (8) periphery is provided with cushion cap (11); cushion cap (11) is on cement mortar protective course (15); fill up concrete outside cushion cap (11) and form elevator shaft base plate; self priming pump (9) is provided with in dewatering well (8); the switch of self priming pump (9) is connected with time switch; precipitation well head is provided with steel deck-plate (12), and the upper shutoff of steel deck-plate (12) has concrete shutoff (14).