CN102787608B - Gravity type foundation pit supporting system under vacuum effect and construction method - Google Patents
Gravity type foundation pit supporting system under vacuum effect and construction method Download PDFInfo
- Publication number
- CN102787608B CN102787608B CN201210295813.9A CN201210295813A CN102787608B CN 102787608 B CN102787608 B CN 102787608B CN 201210295813 A CN201210295813 A CN 201210295813A CN 102787608 B CN102787608 B CN 102787608B
- Authority
- CN
- China
- Prior art keywords
- hole
- drainage body
- vertical drainage
- vacuum
- vertical
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Abstract
The invention discloses a gravity type foundation pit supporting system under a vacuum effect and a construction method. The system comprises a peripheral vertical sealed curtain, a pit top horizontal sealing layer, a transverse drainage body, a slope surface sealing layer, a slope bottom vertical sealed curtain, a pit top vertical drainage body and a slope surface vertical drainage body. The peripheral vertical sealed curtain is downward vertically installed from an outside boundary of a setting range of the pit top horizontal sealing layer; the pit top vertical drainage body is arranged in foundation soil of the setting range of the pit top horizontal sealing layer; the transverse drainage body is arranged on the surface of the foundation soil at a top end of the pit top vertical drainage body; the pit top horizontal sealing layer is formed on the surface of the transverse drainage body; the slope surface vertical drainage body is arranged in the foundation soil inside the pit top vertical drainage body; the slope surface sealing layer is formed on the slope surface vertical drainage body; the slope bottom vertical sealed curtain is formed in a slope foot of a pit bottom. In the gravity type foundation pit supporting system under the vacuum effect and the construction method provided by the invention, a side wall is not arranged to solidify a wall body and a curtain shielding body, a greater cutting depth requirement can be met, construction cost is low and construction period is shorter.
Description
Technical field
The invention belongs to civil construction Base hole supporting technology field, particularly relate to a kind of vacuum action gravity foundation pit supporting system and construction method.
Background technology
A kind of vacuum curtain water stop and atmospheric pressure support deep pit digging method (hereinafter referred " vacuum curtain method ") is disclosed in Chinese invention patent the 200810236142.3rd, the method utilizes vacuum curtain to carry out sealing, and play atmospheric pressure be used for carry out pattern foundation pit supporting structure, construct safer, and without the need to internal support of foundation pit structure, without the need to precipitation well point inside and outside foundation ditch, safe and reliable, save in duration, investment reduction etc. there is comparatively significantly advantage.
Vacuum curtain method mainly comprises the following steps:
The first step, the place of carrying out needed for excavation of foundation pit flatten, and plan vacuum curtain region, namely will lay the region of diaphragm seal around foundation ditch;
Second step, in the soil body in vacuum curtain region, squeeze into vertical drainage body according to the degree of depth of excavation of foundation pit, the degree of depth that described vertical drainage body is squeezed into is greater than the degree of depth of excavation of foundation pit; And carry out the body of wall solidification construction of foundation ditch border, namely sidewall solidification body of wall is set on foundation ditch boundary line;
According to actual conditions needs, wall outer side can be solidified at foundation pit side-wall and window shade body is set, window shade body be arranged through foundation pit side-wall solidification wall outer side driven pile or on-the-spot pile, on-the-spot become the method for wall realize.Window shade body can be Single row pillars or wall, also can be multiline pile or wall.Whether window shade body being set, and its pile-type, layout and quantity when window shade body is set, comprehensively need determine according to the degree of depth of excavation of foundation pit and formation condition;
3rd step, vacuum curtain region lay diaphragm seal, the border of described diaphragm seal is imbedded in the soil body, thus formed vacuum curtain;
4th step, vacuum source to be connected with vertical drainage body, and by the mode that vacuum source vacuumizes, the air pressure in described vacuum curtain to be declined;
5th step, after the negative pressure of vacuum in vacuum curtain reaches and remains on-40kPa ~-85kPa, excavation of foundation pit is carried out under the prerequisite keeping vacuum in vacuum curtain, the mode of stage excavation is adopted to carry out in digging process, after often having excavated a layer soil body, expose the foundation ditch external boundary sidewall that a circle is new, vertical seal isolation processing is carried out along this foundation ditch external boundary sidewall, namely on new hole external boundary sidewall, barrier film is laid, this barrier film seals with the diaphragm seal forming vacuum curtain and is connected, by atmospheric pressure balance lateral soil pressure, and then carry out next layer soil body excavation and the process of this layer of foundation ditch external boundary sidewalls orthogonal seal isolation, until excavation terminates,
6th step, carry out the construction of base plate of foundation pit and sidewall.
But above-mentioned vacuum curtain method has the following disadvantages:
1, although one of advantage of this vacuum curtain method uprightly to excavate, and without the need to putting slope, thus saved earthwork, and taking periphery place can be reduced, but upright excavation also becomes one of its limitation, because upright excavation can make the stability of hole wall reduce, thus the excavation of foundation pit degree of depth making this law apply is restricted, namely after the excavation of foundation pit degree of depth exceedes a certain value, hole wall cannot keep stable, and need the stability maintaining hole wall by means of ancillary methods such as inner supports, and so just lose the cost advantage of vacuum curtain method, duration also can extend greatly.
Describing 2, according to this patent document content, the Main Function arranging sidewall solidification body of wall is fixing excavation of foundation pit boundary shape, the setting of the air water flow rate reducing exterior domain in foundation ditch border, assisted vacuum curtain and foundation ditch SEQUENCING VERTICAL seal isolation film and foundation pit side-wall build exterior sheathing, in particular cases can also play the effect of cutting down small part foundation ditch lateral earth pressure.But be not difficult to find out, excavation of foundation pit boundary shape this point is still fixed in the topmost effect of sidewall solidification body of wall.Why vacuum curtain method needs to arrange sidewall solidification body of wall fixes excavation of foundation pit boundary shape, is also because its way uprightly excavated causes.The natural soil body, especially weak soil, as excavated into upright side slope, very easily occur collapsing, at least easily occur collapsing in local, in order to prevent cheat wall collapse arrange sidewall solidification body of wall be required, but will increase like this arrange sidewall solidification body of wall engineering quantity, for reduction cost unfavorable.
3, in some cases, vacuum curtain method needs to arrange window shade body in sidewall solidification wall outer side, window shade body be arranged through foundation pit side-wall solidification wall outer side driven pile or on-the-spot pile, on-the-spot become the method for wall realize.The object arranging window shade body and actual role are not described in this patent document, but by analyzing, window shade body roughly has following two effects: one is when window shade body is for sealing body of wall, it can play the sealing function of auxiliary sidewall solidification body of wall and vertical seal barrier film oppose side wall deep soil, prevents the vacuum pressure in vacuum curtain from leaking; Two is utilize window shade body deeply to cheat stability that the wedge action of end ground and the bending resistance of self, shear structure intensity directly strengthen hole wall, namely stablizes to hole wall the effect playing assistant reinforcement.In this case, window shade body is a kind of assistant reinforcement measure, if take other measure, allows vacuum seal and hole wall stablize and is guaranteed, then can arrange window shade body, to save the cost arranging this part engineering of window shade body.
4, to lay the method for processing foundation of the mode of diaphragm seal and traditional vacuum preloading similar top, vacuum curtain method hole, the outer boundaries of diaphragm seal is that shallow embedding simply enters in the soil body, thus easily make the vacuum pressure in vacuum curtain spread laterally, and the diffusion of vacuum pressure can reduce the vacuum within the scope of curtain on the one hand, thus reduce the buckling safety factor of hole wall, the ground in adjacent domain certain limit can be made to shrink on the one hand in addition, ftracture and depression, harmful effect is caused to surrounding environment.And because this method sealing effect is realized by vacuum pumping action, can have in fact the effect of precipitation to the ground of foundation ditch periphery, when surrounding environment is responsive for dewatering of foundation, then this method is inapplicable.
Summary of the invention
In order to solve the problem, a kind of needs is the object of the present invention is to provide sidewall solidification body of wall and window shade body to be set, the vacuum action gravity foundation pit supporting system that larger cutting depth requires, cost is lower, the duration is shorter can be met.
Another object of the present invention is to the construction method that a kind of above-mentioned vacuum action gravity foundation pit supporting system is provided.
In order to achieve the above object, vacuum action gravity foundation pit supporting system provided by the invention comprises vertical airtight curtain, hole top vertical drainage body and domatic vertical drainage body at the bottom of peripheral vertical airtight curtain, the horizontal confined layer in top, hole, transverse row water body, domatic confined layer, slope; Wherein peripheral vertical airtight curtain arranges scope outer boundaries from hole top horizontal confined layer to arrange downward vertically from top, hole original ground and formed; Top, hole vertical drainage body arranges at the horizontal confined layer in top, hole in the foundation soil in scope evenly to arrange, and the Bottom Altitude of top, hole vertical drainage body is lower than the elevation on ground, the end, maximum dredging depth hole; Transverse row water body is arranged on the foundation soil surface on vertical drainage body top, top, hole, and inner horizontal is laid with the vacuum chimney filter of distributed in grid, vacuum chimney filter passes the horizontal confined layer in top, hole by pipeline membrane device, is connected on vacuum pump via outside vacuum-pumping pipeline; The horizontal confined layer in top, hole lays one or more layers geotextiles and one or more layers geomembrane, or directly lay one or more layers composite geo-membrane and formed, and the vertical airtight curtain upper end of outer ledge and periphery is tightly connected, underground is then imbedded by sealing ditch in inner side; Domatic vertical drainage body is arranged in the foundation soil inside the vertical drainage body of top, hole, and it is identical that the bottom elevation of vertical drainage body is pushed up in its bottom elevation and hole, top elevation then with ought locate to excavate domatic consistent; Domatic confined layer to trip out hole top horizontal confined layer being positioned at the geotextiles of inner side and geomembrane or composite geo-membrane from sealing ditch and to cover the domatic vertical drainage body that newly sets and formed; Vertical airtight curtain at the bottom of slope vertically sets a circle water-stopping steel sheet pile at base slope pin place, hole and formed, the lower edge of water-stopping steel sheet pile upper end and domatic confined layer is tightly connected, and the top elevation of vertical airtight curtain at the bottom of slope is higher than the elevation on ground, the end, maximum dredging depth hole.
The vertical airtight curtain in described periphery adopts and vertically lays geomembrane, water jetting makes diaphragm wall, slotting becomes wall method, Make the cutoff wall by sawing channel method, catheter reverse circulation method, grab bucket method become wall, vibrating grooving method becomes wall, sheet pile wall engineering method becomes wall, deep-layer stirring engineering method becomes wall, slip casting method Cheng Qiang, high spray Cheng Qiang, native consolidation engineering method become wall, self-hardening slurry method becomes wall, SMW engineering method becomes wall to become a kind of method in wall to arrange with TRD engineering method.
Described hole top vertical drainage body and domatic vertical drainage body are made up of the one in plastic draining board, sand wick and plastic drain-pipe.
Described transverse row water body is the sand cushion be made up of the medium coarse sand of 0.4 ~ 0.6 meter of thickness.
Described vacuum chimney filter tube wall is evenly distributed with filter opening, and external surface is coated with layer of non-woven fabric, vacuum chimney filter adopts the PVC filter pipe of φ 50mm, chimney filter spacing 8m.
The upper end of described water-stopping steel sheet pile is with the device being convenient to be tightly connected with domatic confined layer.
The construction method of vacuum action gravity foundation pit supporting system provided by the invention comprises the following step carried out in order:
1) scope outer boundaries place is set at the horizontal confined layer in top, hole and peripheral vertical airtight curtain is set downward vertically from top, hole original ground;
2) arrange at the horizontal confined layer in top, hole in the foundation soil in scope and top, hole vertical drainage body is set, and the Bottom Altitude of top, hole vertical drainage body is lower than the elevation on ground, the end, maximum dredging depth hole;
3) transverse row water body is set on the foundation soil surface on the vertical drainage body top, top, hole set, lays the vacuum chimney filter of distributed in grid in transverse row water body inner horizontal;
4) one or more layers geotextiles and one or more layers geomembrane is laid on the surface of transverse row water body, or directly lay one or more layers composite geo-membrane, form the horizontal confined layer in top, hole thus, and the vertical airtight curtain upper end of its outer ledge and periphery is tightly connected, underground is then imbedded by sealing ditch in inner side;
5) above-mentioned vacuum chimney filter is passed the horizontal confined layer in top, hole by pipeline membrane device, be connected on vacuum pump via outside vacuum-pumping pipeline;
6) open vacuum pump, treat that the foundation soil degree of consolidation of foundation pit side-wall reaches after 10% ~ 80%, excavation pit under the condition constantly vacuumized;
7) dark 1m is often dug, the construction of domatic vertical drainage body is progressively carried out in foundation soil inside the vertical drainage body of top, hole, its spacing, arrangement are all identical with top, hole vertical drainage body, it is identical that the bottom elevation of vertical drainage body push up in domatic vertical drainage body bottom elevation and hole, domatic vertical drainage body top elevation then with ought locate to excavate domatic consistent;
8) by hole top horizontal confined layer is positioned at the geotextiles of inner side and geomembrane or composite geo-membrane from sealing ditch trip out and cover newly set part domatic vertical drainage body, the domatic confined layer of forming section thus, then imbeds the sealing ditch at the end, hole again;
9) step 7 is repeated) and 8), until excavation is to the projected depth of foundation ditch;
10) a circle water-stopping steel sheet pile is vertically set at base slope pin place, hole, form vertical airtight curtain at the bottom of slope thus, and the lower edge of water-stopping steel sheet pile upper end and domatic confined layer is tightly connected, the top elevation of vertical airtight curtain at the bottom of slope cheats the elevation on ground, the end higher than maximum dredging depth;
11) build base plate of foundation pit, carry out the construction of building under ground portion structure;
12) stop vacuumizing, then remove vertical airtight curtain at the bottom of slope, domatic confined layer, the hole horizontal confined layer in top and the vertical airtight curtain of part peripheral, and to the in addition recycling of steel plate for sealing water oil and pile work film wherein;
13) foundation soil is backfilling into the space between foundation pit walls and building under ground portion structure, until reach natural ground level, pattern foundation pit supporting structure and excavation work so far all complete.
Traditional foundation pit supporting system is divided into cement-soil mixing pile retaining wall type, sheet pile formula (steel sheet pile, steel pipe pile etc.), campshed formula (bored pile, digging hole filling pile etc.), diaphragm wall, reinforced cement retaining wall supporting (SMW engineering method), stability of slope formula (bolt-spary supports, plate brad supporting) by its operating principle and material behavior, inverse makes the type such as arch wall type, open caisson (case) method.The supporting of cement-soil mixing pile retaining wall type belongs to gravity retaining wall, and it relies on the weight of body of wall own and rigidity to carry out gear soil, maintains it and stablizes, and simultaneously again as water-stop curtain, has the double action of gear soil and sealing.Vacuum action gravity foundation pit supporting system provided by the invention belongs to gravity retaining wall in essence, and body of wall has the double action of gear soil and sealing.
Vacuum action gravity foundation pit supporting system provided by the invention belongs to gravity retaining structure, itself and the topmost difference of cement-soil mixing pile barricade are that it adds vertical drainage body method with vacuum is reinforced the soil body of cheating outside wall in scope of design, instead of the physical chemistry solidification of cement mixing method to the soil body in scope of design outside the wall of hole to form Gravity Retaining Wall.
As all gravity retaining walls, hole wall gravity retaining wall in vacuum action gravity foundation pit supporting system mainly needs the destruction of resisting three types, i.e. resistant slide destruction, the anti-shearing destruction in wall body cross section at the bottom of wall body overturning or slip resistance analysis destruction, wall, but composition that drag that its opposing destroys is originated is but different with the gravity retaining wall of common employing barnacle body, sheet stone concrete or concrete material.The drag source that its opposing destroys is composed as follows:
1, the overturning or slip resistance analysis of wall body destroys drag source composition:
Soil body deadweight and top, hole atmospheric pressure.
2, resistant slide destroys drag source composition:
Under negative pressure of vacuum effect, effective stress obtains the anti-shearing force that the substrate soil strength after strengthening plays.
3, anti-shearing destruction drag source, wall body cross section composition:
Under negative pressure of vacuum effect, effective stress obtains the anti-shearing force that the wall body cross section soil strength after strengthening produces.
The present invention is by cheap vacuum consolidation draining effect, the intensity of slope soil self is made to obtain larger growth, generally within the time of 2 ~ 3 months, the intensity of foundation soil can be improved 2 ~ 3 times, utilize negative pressure of vacuum effect to improve the effective stress of the soil body instantaneously fully simultaneously, thus greatly improve the intensity of foundation soil once again, and utilize vacuum to draw water with domatic confined layer sealing function to reach the dual purpose of sealing and stability of slope, can not arrange inner support, cost and speed of application have obvious advantage.Vacuum action gravity foundation pit supporting system tool provided by the invention has the following advantages:
1, can the foundation ditch of the supporting more heavy excavation degree of depth.In theory, if do not consider that the maximum of vertical drainage body arranges the degree of depth, as long as have enough plane spaces around for layout supporting and protection structure, the excavation of foundation pit degree of depth of vacuum action gravity foundation pit supporting system institute provided by the invention supporting can be unrestricted, because it can ensure the stability of deep foundation ditch by putting the enough mild side slope in slope.Certainly, in Practical Project, excessively dark foundation ditch, such as the degree of depth is more than 50m, substantially also unrealistic, because the excavation of foundation pit degree of depth is genuine so large, the mode of the underground excavations such as employing shield structure should be more convenient and economical than open cut.
2, without the need to arranging sidewall solidification body of wall, construction costs can be reduced.Vacuum action gravity foundation pit supporting system provided by the invention, slope excavation is put because combine, the shape of foundation pit side-wall itself compares and is conducive to maintaining homeostasis, and the foundation soil body inside and outside foundation ditch is improve intensity by vacuum consolidation effect, the shape of excavation of foundation pit border and foundation pit side-wall is easy to be maintained, thus without the need to arranging sidewall solidification body of wall, reduce construction costs.
3, without the need to arranging window shade body in sidewall solidification wall outer side, construction costs can be reduced.Vacuum action gravity foundation pit supporting system provided by the invention, slope excavation is put because combine, the buckling safety factor of foundation pit side-wall is very high, and the obturation effect of domatic confined layer is because be in favourable installation site, obturation effect is also guaranteed, so without the need to arranging window shade body in sidewall solidification wall outer side again, reduce further construction costs.
4, owing to being provided with peripheral vertical airtight curtain, the diffusion of vacuum pressure be greatly limit.Such one side can with the less vacuum vacuumizing power and ensure well to arrange within the scope of vertical drainage body, thus also ensure that the stability and safety of hole wall, on the one hand the iris action of peripheral vertical airtight curtain to vacuum pressure it also avoid adjacent domain ground and shrinks, ftractures and depression in addition, greatly reduces the harmful effect of surrounding environment.Equally, the precipitation effect of the present invention to the ground of foundation ditch periphery has also farthest been limited, and further reduces the impact on surrounding environment.
5, set vertical drainage body in the present invention, lay the speed of application of horizontal drainage body and diaphragm seal etc. all quickly, and, because without the need to arranging inner support, decrease the engineering time that this procedure of inner support is set on the one hand and saved the cost of inner support, in addition on the one hand because there is no the interference of inner support in the space of excavation, the scope of operation is open, greatly can also accelerate the speed of cutting the earth, save the cost of cutting the earth, so the construction of vacuum action gravity foundation pit supporting system provided by the invention is very convenient, also save the valuable duration.
Because vacuum adds the relative cement mixing method of vertical drainage body, there is obvious cost and duration advantage, so vacuum action gravity foundation pit supporting system has obvious cost and duration advantage relative to cement-soil mixing pile retaining wall system.In addition, because the present invention have can supporting more the heavy excavation degree of depth foundation ditch, without the need to arranging sidewall solidification body of wall, without the need in the diffusion that sidewall solidification wall outer side arranges window shade body, peripheral vertical airtight curtain greatly limit vacuum pressure, thus substantially reduce advantages such as the harmful effects of surrounding environment, therefore in technology and economical two, be all better than prior art vacuum curtain method.
Accompanying drawing explanation
Fig. 1 is vacuum action gravity foundation pit supporting system cross-sectional configuration schematic diagram provided by the invention.
Fig. 2 is vacuum action gravity foundation pit supporting system floor map provided by the invention.
In figure:
Top, 1-hole original ground
The peripheral vertical airtight curtain of 2-
The horizontal confined layer in top, 3-hole
4-transverse row water body
The domatic confined layer of 5-
Ground, the end, 6-maximum dredging depth hole
Vertical airtight curtain at the bottom of 7-slope
Top, 8-hole vertical drainage body
The domatic vertical drainage body of 9-
Detailed description of the invention
Below in conjunction with drawings and Examples, vacuum action gravity foundation pit supporting system provided by the invention and construction method are described in detail.
Certain base pit engineering, digs dark 20m, and the planar dimension of excavation is 20m × 150m.
The situation of three layers of foundation soil is respectively:
1. silty clay, thickness 28 meters, grayish green, grey is to Dark grey, and stream moulds soft moulding, saturated, based on the silty clay of glutinous grain and powder, the solubility salt crystal that the black containing 10% is organic and a large amount of.Natural unit weight γ=16.0kN/m
3, moisture content 61%, void ratio 1.6, index of plasticity I
p=22.1, C
u=10.0kPa, φ
u=3.0 °, Basic bearing ability σ
0=80kPa, osmotic coefficient k≤1 × 10
-7m/s, belong to low-intensity, high-compressibility soil, engineering properties is poor.
2. opaque fine sand ~ medium sand, thickness 7 meters, light brown to Dark grey, closely knit, wet, composition is the sand of particulate to middle grain.The classification of ground construction works belongs to the common soil of II level.Natural unit weight γ=18.0kN/m
3, moisture content 15%, void ratio 0.4, C
u=5.0kPa, φ
u=30.0 °, Basic bearing ability σ
0=180kPa, osmotic coefficient k≤1 × 10
-4m/s.
3. sandy gravel, thickness is greater than 10 meters, dark-brown, closely knit particulate to middle coarse grain sandy gravel, containing the solubility salt of adularescent.The classification of ground construction works belongs to the common soil of II level.Natural unit weight γ=22.0kN/m
3, void ratio 0.5, C
u=0kPa, φ
u=40.0 °, Basic bearing ability σ
0=300kPa, osmotic coefficient k≤1 × 10
-3m/s.
As shown in Figure 1 and Figure 2, vacuum action gravity foundation pit supporting system provided by the invention comprises vertical airtight curtain 7, hole top vertical drainage body 8 and domatic vertical drainage body 9 at the bottom of peripheral vertical airtight curtain 2, the horizontal confined layer in top, hole 3, transverse row water body 4, domatic confined layer 5, slope; Wherein peripheral vertical airtight curtain 2 arranges scope outer boundaries from hole top horizontal confined layer 3 to arrange downward vertically from top, hole original ground 1 and formed; Top, hole vertical drainage body 8 arranges at the horizontal confined layer 3 in top, hole in the foundation soil in scope evenly to arrange, and the Bottom Altitude of top, hole vertical drainage body 8 is lower than the elevation on ground, the end 6, maximum dredging depth hole; Transverse row water body 4 is arranged on the foundation soil surface on vertical drainage body 8 top, top, hole, and inner horizontal is laid with the vacuum chimney filter of distributed in grid, vacuum chimney filter passes the horizontal confined layer 3 in top, hole by pipeline membrane device, is connected on vacuum pump via outside vacuum-pumping pipeline; The horizontal confined layer 3 in top, hole lays one or more layers geotextiles and one or more layers geomembrane, or directly lay one or more layers composite geo-membrane and formed, and vertical airtight curtain 2 upper end of outer ledge and periphery is tightly connected, underground is then imbedded by sealing ditch in inner side; Domatic vertical drainage body 9 is arranged in the foundation soil inside the vertical drainage body 8 of top, hole, and it is identical that the bottom elevation of vertical drainage body 8 is pushed up in its bottom elevation and hole, top elevation then with ought locate to excavate domatic consistent; Domatic confined layer 5 to trip out hole top horizontal confined layer 3 being positioned at the geotextiles of inner side and geomembrane or composite geo-membrane from sealing ditch and to cover the domatic vertical drainage body 9 that newly sets and formed; Vertical airtight curtain 7 at the bottom of slope vertically sets a circle water-stopping steel sheet pile at base slope pin place, hole and formed, the lower edge of water-stopping steel sheet pile upper end and domatic confined layer 5 is tightly connected, and the top elevation of vertical airtight curtain 7 at the bottom of slope is higher than the elevation on ground, the end 6, maximum dredging depth hole.
The construction method of vacuum action gravity foundation pit supporting system provided by the invention comprises the following step carried out in order:
1) scope outer boundaries place is set at the horizontal confined layer 3 in top, hole and vertically lays geomembrane from the employing downwards of top, hole original ground 1, water jetting makes diaphragm wall, slotting becomes wall method, Make the cutoff wall by sawing channel method, catheter reverse circulation method, grab bucket method becomes wall, vibrating grooving method becomes wall, sheet pile wall engineering method becomes wall, deep-layer stirring engineering method becomes wall, slip casting method becomes wall, high spray becomes wall, soil consolidation engineering method becomes wall, self-hardening slurry method becomes wall, SMW engineering method becomes wall to become a kind of method in wall to arrange peripheral vertical airtight curtain 2 with TRD engineering method, this engineering is that the method adopting fluting to lay the dark composite geo-membrane of 10m arranges peripheral vertical airtight curtain 2,
2) arrange at the horizontal confined layer 3 in top, hole in the foundation soil in scope and top, hole vertical drainage body 8 is evenly set, top, hole vertical drainage body 8 is made up of the one in plastic draining board, sand wick and plastic drain-pipe, and the Bottom Altitude of top, hole vertical drainage body 8 is lower than the elevation on ground, the end 6, maximum dredging depth hole; In this engineering, top, hole vertical drainage body 8 adopts plastic draining board, and the degree of depth is 25m, arranged in squares, and spacing is 1m, and plastic draining board Bottom Altitude is lower than the elevation 5m on ground, the end 6, maximum dredging depth hole;
3) transverse row water body 4 is set on the foundation soil surface on vertical drainage body 8 top, top, hole set, the vacuum chimney filter of distributed in grid is laid in transverse row water body 4 inner horizontal, transverse row water body 4 is the sand cushion be made up of the medium coarse sand of 0.4 ~ 0.6 meter of thickness, this engineering first lays one deck 0.3m thick medium coarse sand bottom sand mat of subgrade on the foundation soil surface on vertical drainage body 8 top, top, hole, then on bottom sand mat of subgrade, level lays the vacuum chimney filter of distributed in grid, vacuum chimney filter tube wall is evenly distributed with filter opening, and external surface is coated with layer of non-woven fabric, water can be allowed like this, gas enters in vacuum chimney filter, prevent sand grains from entering vacuum chimney filter simultaneously, vacuum chimney filter adopts the PVC filter pipe of φ 50mm, and chimney filter spacing 8m, then re-lays one deck 0.2m thick medium coarse sand top layer sand mat of subgrade on vacuum chimney filter top, forms by bottom sand mat of subgrade and top layer sand mat of subgrade the transverse row water body 4 that thickness is 0.5 meter,
4) one or more layers geotextiles and one or more layers geomembrane is laid on the surface of transverse row water body 4, or directly lay one or more layers composite geo-membrane, form the horizontal confined layer 3 in top, hole thus, and vertical airtight curtain 2 upper end of its outer ledge and periphery is tightly connected, underground is then imbedded by sealing ditch in inner side; Cheat in this engineering the horizontal confined layer 3 in top for one deck width be the composite geo-membrane of 20m;
5) above-mentioned vacuum chimney filter is passed the horizontal confined layer 3 in top, hole by pipeline membrane device, be connected on vacuum pump via outside vacuum-pumping pipeline; The way of pipeline membrane device is consistent with common vacuum prepressing ground foundation treatment method.Vacuum pump adopts jet pump, and separate unit power is 7.5kW, and under no-load condition, vacuum pressure is more than 96kPa, and the area of plane that every platform vacuum pump is reinforced is not more than 800m
2, this engineering has configuration 30 vacuum pumps altogether;
6) open vacuum pump, treat that the foundation soil degree of consolidation of foundation pit side-wall reaches 10-80% excavation pit later; Excavation carries out according to the gradient designed, excavate the gradient in this engineering and be set as 1: 1, the controlling value Main Basis design a rate of advance of the foundation soil degree of consolidation before excavation is determined, a rate of advance is faster, the foundation soil degree of consolidation then before excavation requires higher, and the foundation soil degree of consolidation before this engineering excavation is 30%;
7) dark 1m is often dug, the construction of domatic vertical drainage body 9 is progressively carried out in foundation soil inside the vertical drainage body 8 of top, hole, its spacing, arrangement are all identical with top, hole vertical drainage body 8, it is identical that the bottom elevation of vertical drainage body 8 push up in domatic vertical drainage body 9 bottom elevation and hole, domatic vertical drainage body 9 top elevation then with ought locate to excavate domatic consistent; In this engineering, domatic vertical drainage body 9 adopts plastic draining board, the degree of depth be 4.5m ~ 23.5m not etc., arranged in squares, spacing is 1m;
8) by hole top horizontal confined layer 3 is positioned at the geotextiles of inner side and geomembrane or composite geo-membrane from sealing ditch trip out and cover newly set part domatic vertical drainage body 9, the domatic confined layer 5 of forming section thus, then imbeds the sealing ditch at the end, hole again;
9) step 7 is repeated) and 8), until excavation is to the projected depth of foundation ditch;
10) a circle water-stopping steel sheet pile is vertically set at base slope pin place, hole, form vertical airtight curtain 7 at the bottom of slope thus, and the lower edge of water-stopping steel sheet pile upper end and domatic confined layer 5 is tightly connected, the top elevation of vertical airtight curtain 7 at the bottom of slope cheats the elevation on ground, the end 6 higher than maximum dredging depth, and the upper end of water-stopping steel sheet pile is with the device being convenient to be tightly connected with domatic confined layer 5; In this engineering, the length of sealing steel sheet pile is 3m, and top elevation is than the elevation height 0.5m on ground, the end 6, maximum dredging depth hole;
11) build base plate of foundation pit, carry out the construction of building under ground portion structure;
12) stop vacuumizing, then remove vertical airtight curtain 7 at the bottom of slope, domatic confined layer 5, the hole horizontal confined layer 3 in top and the vertical airtight curtain 2 of part peripheral, and to the in addition recycling of water-stopping steel sheet pile wherein and composite geo-membrane;
13) foundation soil is backfilling into the space between foundation pit walls and building under ground portion structure, until reach natural ground level, pattern foundation pit supporting structure and excavation work so far all complete.
If this engineering adopts bored pile, collar tie beam and Guan Liang to add inner support supporting, the supporting scheme of cement mixing method and high-pressure rotary jet grouting pile sealing, total cost will be 4,080,000 yuan, 11 months durations, and adopting the cost of this programme to only have 2,300,000 yuan, 6 months durations, cost reduces by one times nearly as can be seen here, duration shortens half simultaneously, and therefore economic benefit is very remarkable.
Claims (7)
1. a vacuum action gravity foundation pit supporting system, is characterized in that: described vacuum action gravity foundation pit supporting system comprises vertical airtight curtain (7), top vertical drainage body, hole (8) and domatic vertical drainage body (9) at the bottom of peripheral vertical airtight curtain (2), the horizontal confined layer in top, hole (3), transverse row water body (4), domatic confined layer (5), slope; Wherein peripheral vertical airtight curtain (2) arranges scope outer boundaries from the horizontal confined layer in top, hole (3) to arrange downward vertically from top original ground, hole (1) and formed; Top vertical drainage body, hole (8) arranges in the horizontal confined layer in top, hole (3) in the foundation soil in scope evenly to arrange, and the Bottom Altitude in top vertical drainage body, hole (8) is lower than the elevation of maximum dredging depth ground, the end, hole (6); Transverse row water body (4) is arranged on the foundation soil surface on vertical drainage body (8) top, top, hole, and inner horizontal is laid with the vacuum chimney filter of distributed in grid, vacuum chimney filter passes the horizontal confined layer in top, hole (3) by pipeline membrane device, is connected on vacuum pump via outside vacuum-pumping pipeline; The horizontal confined layer in top, hole (3) lays one or more layers geotextiles and one or more layers geomembrane, or directly lay one or more layers composite geo-membrane and formed, and outer ledge and periphery vertical airtight curtain (2) upper end is tightly connected, underground is then imbedded by sealing ditch in inner side; Domatic vertical drainage body (9) is arranged in the foundation soil of inner side, top vertical drainage body, hole (8), and it is identical that the bottom elevation of vertical drainage body (8) is pushed up in its bottom elevation and hole, top elevation then with work as locate to excavate domatic consistent; Domatic confined layer (5) to trip out the hole horizontal confined layer in top (3) being positioned at the geotextiles of inner side and geomembrane or composite geo-membrane from sealing ditch and to cover the domatic vertical drainage body (9) that newly sets and formed; Vertical airtight curtain (7) at the bottom of slope vertically sets a circle water-stopping steel sheet pile at base slope pin place, hole and formed, the lower edge of water-stopping steel sheet pile upper end and domatic confined layer (5) is tightly connected, and the top elevation of vertical airtight curtain (7) at the bottom of slope is higher than the elevation of maximum dredging depth ground, the end, hole (6).
2. vacuum action gravity foundation pit supporting system according to claim 1, is characterized in that: the vertical airtight curtain in described periphery (2) adopts and vertically lays geomembrane, water jetting makes diaphragm wall, slotting becomes wall method, Make the cutoff wall by sawing channel method, catheter reverse circulation method, grab bucket method become wall, vibrating grooving method becomes wall, sheet pile wall engineering method becomes wall, deep-layer stirring engineering method becomes wall, slip casting method Cheng Qiang, high spray Cheng Qiang, native consolidation engineering method become wall, self-hardening slurry method becomes wall, SMW engineering method becomes wall to become a kind of method in wall to arrange with TRD engineering method.
3. vacuum action gravity foundation pit supporting system according to claim 1, is characterized in that: described top vertical drainage body, hole (8) and domatic vertical drainage body (9) are made up of the one in plastic draining board, sand wick and plastic drain-pipe.
4. vacuum action gravity foundation pit supporting system according to claim 1, is characterized in that: described transverse row water body (4) is the sand cushion be made up of the medium coarse sand of 0.4 ~ 0.6 meter of thickness.
5. vacuum action gravity foundation pit supporting system according to claim 1, it is characterized in that: described vacuum chimney filter tube wall is evenly distributed with filter opening, and external surface is coated with layer of non-woven fabric, vacuum chimney filter adopts the PVC filter pipe of φ 50mm, chimney filter spacing 8m.
6. vacuum action gravity foundation pit supporting system according to claim 1, is characterized in that: the upper end of described water-stopping steel sheet pile is with the device being convenient to be tightly connected with domatic confined layer (5).
7. a construction method for vacuum action gravity foundation pit supporting system as claimed in claim 1, is characterized in that: described construction method comprises the following step carried out in order:
1) scope outer boundaries place is set in the horizontal confined layer in top, hole (3) peripheral vertical airtight curtain (2) is set downward vertically from top original ground, hole (1);
2) arrange in the horizontal confined layer in top, hole (3) in the foundation soil in scope and top vertical drainage body, hole (8) is set, and the Bottom Altitude in top vertical drainage body, hole (8) is lower than the elevation of maximum dredging depth ground, the end, hole (6);
3) transverse row water body (4) is set on the foundation soil surface on vertical drainage body (8) top, top, hole set, lays the vacuum chimney filter of distributed in grid in transverse row water body (4) inside;
4) one or more layers geotextiles and one or more layers geomembrane is laid on the surface of transverse row water body (4), or directly lay one or more layers composite geo-membrane, form the horizontal confined layer in top, hole (3) thus, and its outer ledge and periphery vertical airtight curtain (2) upper end is tightly connected, underground is then imbedded by sealing ditch in inner side;
5) above-mentioned vacuum chimney filter is passed the horizontal confined layer in top, hole (3) by pipeline membrane device, be connected on vacuum pump via outside vacuum-pumping pipeline;
6) open vacuum pump, treat that the foundation soil degree of consolidation of foundation pit side-wall reaches after 10% ~ 80%, excavation pit under the condition constantly vacuumized;
7) dark 1m is often dug, the construction of domatic vertical drainage body (9) is progressively carried out in the foundation soil of inner side, top vertical drainage body, hole (8), its spacing, arrangement are all identical with top vertical drainage body, hole (8), it is identical that the bottom elevation of vertical drainage body (8) push up in domatic vertical drainage body (9) bottom elevation and hole, domatic vertical drainage body (9) top elevation then with ought locate to excavate domatic consistent;
8) by top, hole horizontal confined layer (3) is positioned at the geotextiles of inner side and geomembrane or composite geo-membrane from sealing ditch trip out and cover newly set part domatic vertical drainage body (9), the domatic confined layer of forming section (5) thus, then imbeds the sealing ditch at the end, hole again;
9) step 7 is repeated) and 8), until excavation is to the projected depth of foundation ditch;
10) a circle water-stopping steel sheet pile is vertically set at base slope pin place, hole, form vertical airtight curtain (7) at the bottom of slope thus, and the lower edge of water-stopping steel sheet pile upper end and domatic confined layer (5) is tightly connected, the top elevation of vertical airtight curtain (7) at the bottom of slope cheats the elevation on ground, the end (6) higher than maximum dredging depth;
11) build base plate of foundation pit, carry out the construction of building under ground portion structure;
12) stop vacuumizing, then vertical airtight curtain (7) at the bottom of slope, domatic confined layer (5), the horizontal confined layer in top, hole (3) and the vertical airtight curtain (2) of part peripheral is removed, and to the in addition recycling of water-stopping steel sheet pile wherein and geomembrane;
13) foundation soil is backfilling into the space between foundation pit walls and building under ground portion structure, until reach natural ground level, pattern foundation pit supporting structure and excavation work so far all complete.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210295813.9A CN102787608B (en) | 2012-08-17 | 2012-08-17 | Gravity type foundation pit supporting system under vacuum effect and construction method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210295813.9A CN102787608B (en) | 2012-08-17 | 2012-08-17 | Gravity type foundation pit supporting system under vacuum effect and construction method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102787608A CN102787608A (en) | 2012-11-21 |
| CN102787608B true CN102787608B (en) | 2015-04-22 |
Family
ID=47153182
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210295813.9A Active CN102787608B (en) | 2012-08-17 | 2012-08-17 | Gravity type foundation pit supporting system under vacuum effect and construction method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102787608B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104746521B (en) * | 2013-07-08 | 2016-08-24 | 天津大学 | The application of oversized cross-section slope cushion layer constructing structure |
| CN104153344A (en) * | 2014-05-06 | 2014-11-19 | 宁波职业技术学院 | Soft foundation treatment method |
| CN109972633B (en) * | 2019-04-30 | 2021-08-31 | 宁夏勇峰建筑工程有限公司 | Vacuum support for foundation pit |
| CN114737555A (en) * | 2022-03-02 | 2022-07-12 | 河海大学 | Soft foundation reinforcing method based on thermal effect and vacuum film semi-wrapping process |
| CN118065406B (en) * | 2024-04-22 | 2024-08-30 | 北京建工四建工程建设有限公司 | Sinking type temporary slope building for easily-degraded slope |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005002659A (en) * | 2003-06-11 | 2005-01-06 | East Japan Railway Co | Groundwater circulation system in excavation of ground, and construction method for measure against groundwater in excavation of ground |
| CN100575616C (en) * | 2008-11-25 | 2009-12-30 | 南京水利科学研究院勘测设计院 | Vacuum curtain water stop and atmospheric pressure support deep pit digging construction method |
| CN101748734A (en) * | 2008-12-04 | 2010-06-23 | 中国二十冶建设有限公司 | Foundation pit side slope sandy soil drainage method |
| CN101949153B (en) * | 2010-09-14 | 2012-07-04 | 刘远锋 | Foundation drainage control method |
| CN202767088U (en) * | 2012-08-17 | 2013-03-06 | 中国土木工程集团有限公司 | Vacuum effect gravity type foundation trench supporting and protecting system |
-
2012
- 2012-08-17 CN CN201210295813.9A patent/CN102787608B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN102787608A (en) | 2012-11-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103233454B (en) | Processing method of soaking, vacuum preloading and slurry injecting for sand piles of collapsible loess foundation | |
| CN101225656B (en) | Method for rapidly reinforcing ultra-soft soil superficial layer | |
| CN104120710B (en) | A kind of highway on soft ground method of vacuum pre-pressed joint serous fluid of dredger fill | |
| CN102995599B (en) | Anti-freeze anti-seepage water diversion treatment method of collapsible loess water-conveyance canal | |
| CN102787608B (en) | Gravity type foundation pit supporting system under vacuum effect and construction method | |
| CN101806055B (en) | Vacuum pre-pressed joint rigid pile composite foundation reinforcing method | |
| CN111733792B (en) | Soft soil foundation vacuum preloading and power consolidation drainage combined foundation treatment method and system | |
| CN107859041B (en) | The construction method of collapsible loess zanjon high roadbed structure | |
| CN102926376A (en) | Treatment method for soft soil foundation in coastal reclamation region | |
| CN104775415A (en) | Working platform for rapidly reinforcing hydraulic reclamation super-soft soil foundation and construction method | |
| CN103215945B (en) | The three-dimensional assembly power drain consolidation system of heterogeneous body place soft soil foundation and method | |
| CN105804007A (en) | Reinforced soil bank wall structure based on beach soft foundation | |
| CN103967015B (en) | A kind of water seal for deep foundation pit excavation method and structure thereof | |
| CN206448286U (en) | It is a kind of to be used to reduce the radial system of grey field dam seepage line | |
| JP2007303270A5 (en) | ||
| CN110485405B (en) | Reinforcing system and reinforcing method for soft soil foundation | |
| CN106049413B (en) | A kind of composite power drain consolidation system and construction method applied to deep layer foundation in saturated soft soil | |
| CN101886384A (en) | Vacuum and dynamic compaction synchronization method | |
| CN205662938U (en) | Drainage excavation structure falls in foundation ditch | |
| CN202767088U (en) | Vacuum effect gravity type foundation trench supporting and protecting system | |
| CN104746506A (en) | Soft soil combined preloading structure and construction method | |
| CN209260739U (en) | A kind of foundation pit water-stopping system close to river permeable stratum | |
| CN208803456U (en) | A kind of structure for reinforcing peat soil using sand pile and drain bar | |
| CN101775800B (en) | Cement earth pile with double functions and forming method thereof | |
| CN207211176U (en) | A kind of big open caisson of superelevation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |