Foundation pit support construction technology
Technical field
The present invention relates to a kind of foundation pit support construction technologies, are suitable for building field.
Background technique
Since support beam span is very big when large span foundation pit support construction, supporting beam can bear very big pressure, if will
Support beam section becomes larger can be very uneconomical, if supporting beam may go out under the effect of huge axle power using common support beam
Now destroy.In order to reduce the axle power and moment of flexure of supporting beam, often in supporting beam following settings steel lattice column as supporting point, due to
Weak soil is easy to appear Plastic Flow under external force, and steel lattice column is difficult in weak soil accurate positioning, and difficulty of construction is very big.And
Steel lattice column will also anchor into soil layer, and steel lattice column length can be longer, and the cost is relatively high.Furthermore the presence of steel lattice column is to the earthwork
Excavation can also be influenced.Not only safety had been can guarantee when how to solve foundation pit construction but also can easy to operate be the class that engineering staff faces
Topic.
Summary of the invention
The present invention is to provide a kind of foundation pit support construction technology, and the traditional pattern foundation pit supporting structure security performance of solution is bad and operates not
Convenient problem.
The present invention is using the more reasonable feature of annular beam stress, using annular girder as power transmission in foundation pit supporting construction
Structure, and reduce in foundation pit supporting construction the dosage of steel lattice column as far as possible, on the one hand by space truss structure by part
Vertical force is transferred to steel bearing column, and vertical force is passed to steel bearing column additionally by cable wire rope.
Steel bearing column is arranged at foundation pit supporting construction center in the present invention, and pattern foundation pit supporting structure uses two-layer structure, one layer of annular girder
Diameter is 14~24m, and one layer of annular depth of beam is 600~650mm, width 300mm, between one layer of annular girder and steel bearing column
One layer of supporting beam is set, and one layer of support depth of beam is 600~650mm, width 300mm, one layer of annular girder and one layer of supporting beam
Join position and steel lattice column is set, capping beam is set at the top of excavation slope, and the depth of beam that bears down on one is 600~650mm, and width is
300mm is arranged one layer of supporting beam, raker beam is arranged between capping beam and one layer of annular girder between capping beam and one layer of annular girder,
One layer of 1/4 circular arc of annular girder is arranged in along the 1/3 of circular arc direction or 2/3 in raker beam one end, and the setting of the raker beam other end is being pressed
For top beam along its length at 1/4, diagonal brace depth of beam is 600~650mm, width 300mm;Two layers of annular girder diameter are 24~
36m, two layers of annular depth of beam are 500~550mm, width 300mm, than one layer annular depth of beam of two layers of annular girder be high be because of
Later layer annular girder bearing capacity, which is excavated, in two layers of soil layer is greater than one layer of annular girder.It is arranged between two layers of annular girder and steel bearing column
Two layers of supporting beam, two layers of support depth of beam are 500~550mm, width 300mm, and two layers of annular girder and two layers of supporting beam join
The not set steel lattice column in position, two layers of annular girder and two layers of supporting beam handover not set steel lattice column in position both can be convenient shoveling
Waist rail can be arranged in construction again with saving construction cost, excavation slope middle part, and waist rail top mark height and waist rail top mark are high consistent, and waist rail height is
500~550mm, width 300mm, two layers are arranged two layers of supporting beam between annular girder and waist rail.Steel bearing column is higher by one layer of ring
Cable wire rope, cable wire rope and one layer of annular girder drawknot node is arranged in 1.5~1.8m of ellbeam top surface between steel bearing column and one layer of annular girder
It is uniformly distributed along one layer of annular girder circular arc.Steel bearing column protrudes into the following soil layer of basement bottom board to keep anchorage length, steel load
Column bottom end is 1.5~1.7 times of the liftoff lower room bottom plate distance in steel load top end with a distance from basement bottom board.
The steel pipe that steel bearing column uses with a thickness of 15~18mm, steel pipe is interior to be reinforced every 0.5~0.7m setting steel plate,
Join the rectangular preformed hole of position indwelling in steel bearing column and one layer of supporting beam or two layers of supporting beam, rectangular reserved hole depth is 100
~120mm, width and length are identical as one layer of supporting beam or two layers of supporting beam, rectangular preformed hole bottom and top be respectively provided with steel every
Temporary steel cladding plate is arranged in the rectangular preformed hole outside of plate, steel bearing column;One layer of supporting beam or two layers of branch during foundation pit construction
The reinforcing bar of support beam is welded after protruding into rectangular preformed hole with steel diaphragm, and concrete is arranged in rectangular preformed hole.
Steel load column diameter carries out value according to foundation pit maximum span and excavation of foundation pit depth, and foundation pit maximum span is finger pressure
Maximum distance of the top beam inner surface from opposite side capping beam inner surface.According to simulation analysis of computer as a result, steel load column diameter root
According to 1 value of table, when foundation pit maximum span or excavation of foundation pit depth and 1 numerical value of table do not determine steel bearing column using interpolation method simultaneously
Diameter.When longitudinal span and horizontal span are greater than 2, steel bearing column stress can mitigate, and can be held using reduction coefficient to steel
Power column diameter is reduced, and when longitudinal span, which is greater than 1 with horizontal span, is less than or equal to 2, reduction coefficient uses 0.98, works as longitudinal direction
When span and horizontal span are greater than 2 and are less than or equal to 2.3, reduction coefficient uses 0.96, when longitudinal span is greater than with horizontal span
2.3 and when being less than or equal to 2.6, reduction coefficient uses 0.94, when longitudinal span and horizontal span are greater than 2.6 and are less than or equal to 3,
Reduction coefficient uses 0.92, and when longitudinal span is greater than 3 with horizontal span, reduction coefficient uses 0.9.Here horizontal span refers to
The span in relatively large direction, longitudinal span refer to the span in relatively small direction.
1 steel bearing column diameter parameters of table
Construction procedure includes:
(1) construction steel bearing column;Steel bearing column is pressed into soil layer by hydraulic static piling;
(2) install one layer of annular girder, capping beam, one layer of supporting beam and raker beam reinforcing bar, install one layer of annular girder, bear down on one
The template of beam, one layer of supporting beam and raker beam removes the temporary steel cladding plate outside the rectangular preformed hole of steel bearing column, one layer of supporting beam
Reinforcing bar protrude into after rectangular preformed hole and welded with the steel diaphragm of steel bearing column, the casting concrete in rectangular preformed hole, this
Pour one layer of annular girder, capping beam, one layer of supporting beam and raker beam concrete again afterwards;
(3) tensioning cable wire rope;Using three-level tensioning, each grade be respectively 30% proof stress, 60% proof stress and
100% proof stress.
Tensioning platform is set up near steel bearing column, using each cable wire rope of intelligent tensioning equipment simultaneous tension, intelligence
Drawing equipment includes jack, stretching oil pump, tensioning oil cylinder, computer control systems, sensor, and stretching oil pump controls tensioning
Elongation, the installing of tensioning oil cylinder have the two-position two-way solenoid valve of hydraulic bridge, and hydraulic bridge controls the flow direction and flow of oil pressure, simultaneously
There are one check valve in every group of tensioning oil cylinder, main function is can be fast in the short time when problem occurs for hydraulic tube etc.
The function locking of tensioning oil cylinder, effective support of proof load are improved the safety of stretching process by speed.Electronic computer control
System reflects the cable wire rope pressure intracavitary in tensioning cylinder force using cable wire rope stretching extension value variable signal as controlled parameter
Strong variable signal acquires these signals by sensor, and passes the signal to computer control unit.Electronic computer
Control centre is compared and calculates to signal immediately after receiving signal, when wherein certain controlled point has overproof possibility for discovery,
Controller issues command signal at once, allows the two-position two-way solenoid valve generation of the point to act, hydraulic oil stream is closed, to promote this
The tensioning oil cylinder of point rises or falls movement.
(4) reach design strength to one layer of annular girder, capping beam, one layer of supporting beam and raker beam concrete strength
After 100%, the earthwork outside one layer of annular girder is excavated;The earthwork outside one layer of annular girder is excavated using tile and hierarchy, one layer of ring
The earthwork outside ellbeam is divided into four pieces of excavations, excavates and uses symmetric mode, the additional stress generated when being excavated with reducing, and first piece
The diagonal earthwork is excavated after having dug again;Stage excavation is with a thickness of 500~600mm;Earth excavation outside one layer of annular girder is to one
The earthwork inside one layer of annular girder is excavated when half depth again, the earthwork inside one layer of annular girder is excavated using tile and hierarchy, and one layer
The earthwork inside annular girder is divided into four pieces of excavations, and excavation excavates the diagonal earthwork after having dug using symmetric mode, first piece again;Point
Layer excavates with a thickness of 500~600mm;One layer of annular girder is excavated again when earth excavation to half depth inside one layer of annular girder
The remaining earthwork inside one layer of annular girder is finally excavated in the earthwork of external redundant again;
(5) install two layers of annular girder, waist rail, two layers of supporting beam reinforcing bar, install two layers of annular girder, waist rail, two layers of support
The template of beam, removes the temporary steel cladding plate outside the rectangular preformed hole of steel bearing column, and the reinforcing bar of two layers of supporting beam protrudes into rectangular reserved
The steel diaphragm of Kong Houyu steel bearing column is welded, the casting concrete in rectangular preformed hole, hereafter pour again two layers of annular girder,
Waist rail, two layers of supporting beam concrete;
(6) after two layers of annular girder, waist rail, two layers of supporting beam concrete strength reach the 100% of design strength, two are excavated
The earthwork outside layer annular girder;The earthwork outside two layers of annular girder is excavated using tile and hierarchy, the earthwork outside two layers of annular girder
It is divided into four pieces of excavations, excavation excavates the diagonal earthwork after having dug using symmetric mode, first piece again;Stage excavation is with a thickness of 500
~600mm;The earthwork inside two layers of annular girder, two layers of ring are excavated when earth excavation to half depth outside two layers of annular girder again
The earthwork inside ellbeam is excavated using tile and hierarchy, and the earthwork inside two layers of annular girder is divided into four pieces of excavations, is excavated using symmetrical
Mode, first piece dug after excavate the diagonal earthwork again;Stage excavation is with a thickness of 500~600mm;Inside two layers of annular girder
The earthwork of two layers of annular girder external redundant is excavated when earth excavation to half depth again;The basement of two layers of annular girder external range
Bottom plate is divided into four pieces and is poured, and pours sequence and earth excavation sequence consensus, is i.e. is poured after first piece of earth excavation
Build first piece of basement bottom board, other block basement bottom boards and so on;Steel plate water stopper is set between adjacent concrete block;
(7) it is excavated again after the basement bottom board to two layers of annular girder external range pours remaining inside two layers of annular girder
The earthwork;The basement bottom board of two layers of annular girder internal range is divided into four pieces and is poured, and pours sequence and earth excavation sequence
Unanimously, i.e., carry out pouring first piece of basement bottom board after first piece of earth excavation, other block basement bottom boards and so on;
Steel plate water stopper is set between adjacent concrete block;
(8) reinforcing bar of sidewall of basement, template are installed and carries out casting concrete;
(9) supporting construction is removed, demolition of support structure uses double faced leather;First remove two layers of annular girder, waist rail, two
Layer supporting beam;One layer of annular girder, capping beam, one layer of supporting beam and raker beam are removed again;Vertical hole can be used in supporting construction explosion
Or angling hole.Blasting parameter is chosen by following experience:Hole depth is 0.7~0.8 depth of beam, and pitch-row is 0.56~0.8 depth of beam, is adopted
When with quincunx cloth hole, pitch-row is 0.5~0.7 depth of beam;
(10) cable wire rope is removed;
(11) connection for cutting off one layer of supporting beam or two layers of support beam steel and steel bearing column, pulls out steel bearing column.Steel is held
Power column can be with recycling and reusing, with save the cost.
The present invention has a safety feature, and constructing operation is convenient.
Detailed description of the invention
Fig. 1 is one layer of supporting construction schematic diagram, and Fig. 2 is two layers of supporting construction schematic diagram, and Fig. 3 is the signal of supporting construction facade
Figure, Fig. 4 are that one layer of supporting construction excavates schematic diagram, and Fig. 5 is that two layers of supporting construction excavate schematic diagram.
1, steel bearing column, 2, cable wire rope, 3, one layers of annular girder, 4, steel lattice column, 5, one layers of supporting beam, 6, capping beam, 7,
Raker beam, 8, two layers of annular girder, 9, two layers of supporting beam, 10, waist rail.
Specific embodiment
The present embodiment is described in detail below in conjunction with attached drawing.
Steel bearing column 1 is set at foundation pit supporting construction center, pattern foundation pit supporting structure uses two-layer structure, one layer of 3 diameter of annular girder
For 14~24m, one layer of 3 height of annular girder is 600mm, and width 300mm is arranged one between one layer of annular girder 3 and steel bearing column 1
Layer supporting beam 5, one layer of 5 height of supporting beam are 600mm, width 300mm, and one layer of annular girder 3 and one layer of supporting beam 5 join position
Steel lattice column 4 is set, capping beam 6 is set at the top of excavation slope, 6 height of capping beam is 600mm, width 300mm, capping beam 6
One layer of supporting beam 5 is set between one layer of annular girder 3, raker beam 7, raker beam 7 are set between capping beam 6 and one layer of annular girder 3
One layer of 31/4 circular arc of annular girder is arranged in along the 1/3 of circular arc direction or 2/3 in one end, and 7 other end of raker beam is arranged in capping beam 6
Along its length at 1/4,7 height of raker beam is 600mm, width 300mm;Two layers of 8 diameter of annular girder are 24m, two layers of annular
8 height of beam is 500mm, width 300mm.Two layers of supporting beam 9, two layers of support are set between two layers of annular girder 8 and steel bearing column 1
9 height of beam is 500mm, width 300mm, and two layers of annular girder 8 and two layers of supporting beam 9 join the not set steel lattice column 4 in position, base
It cheats side slope middle and waist rail 10 is set, 10 height of waist rail is 500mm, and width 300mm is set between two layers of annular girder 8 and waist rail 10
Set two layers of supporting beam 9.Steel bearing column 1 is higher by one layer of annular girder, 3 top surface 1.6m, is arranged between steel bearing column 1 and one layer of annular girder 3
Cable wire rope 2, cable wire rope 2 are uniformly distributed with one layer of 3 drawknot node of annular girder along one layer of 3 circular arc of annular girder.Steel bearing column 1 protrudes into underground
The following soil layer of room bottom plate, 1 bottom end of steel bearing column are 1 top of steel bearing column with a distance from basement bottom board with a distance from basement bottom board
1.6 again.
1 diameter of steel bearing column uses 0.95m, steel bearing column 1 using the steel pipe with a thickness of 16mm, in steel pipe every 0.5~
0.7m setting steel plate is reinforced, rectangular pre- in steel bearing column 1 and one layer of supporting beam 5 or two layers of handover position indwelling of supporting beams 9
It boxes out, rectangular reserved hole depth is that 100mm, width and length are identical as one layer of supporting beam 5 or two layers of supporting beam 9, rectangular reserved
Hole bottom and top are respectively provided with steel diaphragm, and temporary steel cladding plate is arranged outside the rectangular preformed hole of steel bearing column 1;In foundation pit construction mistake
The reinforcing bar of one layer of supporting beam 5 or two layers of supporting beam 9 is welded after protruding into rectangular preformed hole with steel diaphragm in journey, rectangular preformed hole
Interior setting concrete.
Construction procedure includes:
(1) construction steel bearing column 1;Steel bearing column 1 is pressed into soil layer by hydraulic static piling;
(2) reinforcing bar for installing one layer of annular girder 3, capping beam 6, one layers of supporting beam 5 and raker beam 7, installs one layer of annular girder
3, the template of 6, one layers of supporting beam 5 and raker beam 7 of capping beam removes the temporary steel cladding plate outside the rectangular preformed hole of steel bearing column 1,
The reinforcing bar of one layer of supporting beam 5 is protruded into after rectangular preformed hole and is welded with the steel diaphragm of steel bearing column 1, is poured in rectangular preformed hole
Concrete is built, hereafter pours one layer of annular girder 3,6, one layers of supporting beam 5 of capping beam and 7 concrete of raker beam again;
(3) tensioning cable wire rope 2;Using three-level tensioning, each grade be respectively 30% proof stress, 60% proof stress and
100% proof stress.
Tensioning platform is set up near steel bearing column 1, using each cable wire rope 2 of intelligent tensioning equipment simultaneous tension, intelligence
Tensioning equipment includes jack, stretching oil pump, tensioning oil cylinder, computer control systems, sensor, stretching oil pump control
Elongation is drawn, the installing of tensioning oil cylinder has the two-position two-way solenoid valve of hydraulic bridge, and hydraulic bridge controls the flow direction and flow of oil pressure, together
When in every group of tensioning oil cylinder there are one check valve, main function is can be in the short time when problem occurs for hydraulic tube etc.
Rapidly by the function locking of tensioning oil cylinder, effective support of proof load improves the safety of stretching process.Electronic computer control
System processed reflects that cable wire rope 2 is intracavitary in tensioning cylinder force using 2 stretching extension value variable signal of cable wire rope as controlled parameter
Pressure change signal, these signals are acquired by sensor, and pass the signal to computer control unit.Electrometer
Suan Ji control centre is compared and calculates to signal immediately after receiving signal, when wherein certain controlled point has overproof possibility for discovery
When, controller issues command signal at once, allows the two-position two-way solenoid valve generation of the point to act, hydraulic oil stream is closed, to promote
The tensioning oil cylinder of the point is set to rise or fall movement.
(4) reach design strength to one layer of annular girder 3,6, one layers of supporting beam 5 of capping beam and 7 concrete strength of raker beam
After 100%, the earthwork outside one layer of annular girder 3 is excavated;The earthwork outside one layer of annular girder 3 is excavated using tile and hierarchy, and one layer
The earthwork outside annular girder 3 is divided into four pieces of excavations, excavates and uses symmetric mode, the additional stress generated when being excavated with reducing, the
One piece dug after excavate the diagonal earthwork again;Stage excavation is with a thickness of 500~600mm;Earth excavation outside one layer of annular girder 3
The earthwork inside one layer of annular girder 3 is excavated when to half depth again, the earthwork inside one layer of annular girder 3 is opened using tile and hierarchy
It digs, the earthwork inside one layer of annular girder 3 is divided into four pieces of excavations, and excavation excavates diagonal again after having been dug using symmetric mode, first piece
The earthwork;Stage excavation is with a thickness of 500~600mm;It is excavated again when earth excavation to half depth inside one layer of annular girder 3
One layer of annular girder, the 3 remaining earthwork in inside is finally excavated in the earthwork of one layer of 3 external redundant of annular girder again;
(5) reinforcing bar for installing 10, two layers of two layers of annular girder 8, waist rail supporting beam 9, installs two layers of annular girder 8, waist rail 10, two
The template of layer supporting beam 9, removes the temporary steel cladding plate outside the rectangular preformed hole of steel bearing column 1, and the reinforcing bar of two layers of supporting beam 9 protrudes into
Steel diaphragm after rectangular preformed hole with steel bearing column 1 is welded, hereafter the casting concrete in rectangular preformed hole pours two again
Layer 10, two layers of annular girder 8, waist rail 9 concrete of supporting beam;
(6) it after 10, two layers of two layers of annular girder 8, waist rail 9 concrete strength of supporting beam reach the 100% of design strength, opens
Dig the earthwork outside two layers of annular girder 8;The earthwork outside two layers of annular girder 8 is excavated using tile and hierarchy, outside two layers of annular girder 8
The earthwork be divided into four pieces of excavations, excavate and use symmetric mode, first piece dug after excavate the diagonal earthwork again;Stage excavation thickness
For 500~600mm;The soil inside two layers of annular girder 8 is excavated when earth excavation to half depth outside two layers of annular girder 8 again
Square, the earthwork inside two layers of annular girder 8 is excavated using tile and hierarchy, and the earthwork inside two layers of annular girder 8 is divided into four pieces of excavations, is opened
Dig use symmetric mode, first piece dug after excavate the diagonal earthwork again;Stage excavation is with a thickness of 500~600mm;To two layers of ring
The earthwork of two layers of 8 external redundant of annular girder is excavated when earth excavation to half depth inside ellbeam 8 again;Outside two layers of annular girder 8
The basement bottom board of portion's range is divided into four pieces and is poured, and pours sequence and earth excavation sequence consensus, i.e. first piece of earthwork is opened
Carry out pouring first piece of basement bottom board after digging, other block basement bottom boards and so on;It is set between adjacent concrete block
Set steel plate water stopper;
(7) basement bottom board to two layers of 8 external range of annular girder is excavated again after pouring and is remained inside two layers of annular girder 8
The remaining earthwork;The basement bottom board of two layers of 8 internal range of annular girder is divided into four pieces and is poured, and it is suitable with earth excavation to pour sequence
Sequence is consistent, i.e. carries out pouring first piece of basement bottom board after first piece of earth excavation, other block basement bottom boards successively class
It pushes away;Steel plate water stopper is set between adjacent concrete block;
(8) reinforcing bar of sidewall of basement, template are installed and carries out casting concrete;
(9) supporting construction is removed, demolition of support structure uses double faced leather;First remove two layers of annular girder 8, waist rail
10, two layers of supporting beam 9;One layer of annular girder 3,6, one layers of supporting beam 5 of capping beam and raker beam 7 are removed again;Supporting construction explosion can
Using vertical hole or angling hole.Blasting parameter is chosen by following experience:Hole depth is 0.75 depth of beam, and pitch-row is 0.6 depth of beam, is adopted
When with quincunx cloth hole, pitch-row is 0.6 depth of beam;
(10) cable wire rope 2 is removed;
(11) connection for cutting off one layer of supporting beam 5 or two layers of supporting beam 9 reinforcing bar and steel bearing column 1, pulls out steel bearing column 1.