CN112227384B - Construction method of resistance-increasing large-deformation enclosure structure - Google Patents
Construction method of resistance-increasing large-deformation enclosure structure Download PDFInfo
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- CN112227384B CN112227384B CN202011182385.XA CN202011182385A CN112227384B CN 112227384 B CN112227384 B CN 112227384B CN 202011182385 A CN202011182385 A CN 202011182385A CN 112227384 B CN112227384 B CN 112227384B
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/02—Foundation pits
- E02D17/04—Bordering surfacing or stiffening the sides of foundation pits
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
- E02D5/50—Piles comprising both precast concrete portions and concrete portions cast in situ
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
- F16F15/02—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems
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Abstract
The invention discloses a construction method of a resistance-increasing large-deformation enclosure structure, which belongs to the technical field of support of constructional engineering and comprises an enlarged end, a precast pile, a mixing pile, a cushion layer, an enlarged bottom bag, an inclined pile connecting key, a jack, a vertical pile connecting key, a yielding support, an axial force monitor, an enlarged support, a receiver resistance-increasing groove, a receiver outer wall, a receiver cavity, a propeller main body rod, a propeller body-expanding rod and a propeller protrusion key; the yielding support comprises a support side wall, a buffer damper and a yielding layer; the upper end and the lower end of the buffer damper are provided with annular damper supports; the construction method adopts a resistance-increasing large-deformation enclosure structure for construction, and mainly comprises the following construction steps: preparing and selecting a component; constructing a vertical composite pile; expanding end construction; excavating a foundation pit; constructing an inclined pile structure; constructing an oblique composite pile; debugging the enclosure structure; and finishing the construction. The invention can dynamically adjust according to the supporting condition of the foundation pit at any time, improves the stability of the diagonal brace and reduces the construction period.
Description
Technical Field
The invention relates to the technical field of constructional engineering support, in particular to a construction method of a resistance-increasing large-deformation enclosure structure.
Background
Along with the pace of the urbanization process in China, the development and utilization of underground space are rapidly developed, foundation pit engineering is more and more common, and therefore the enclosure design and construction process of the foundation pit are continuously developed. The foundation pit engineering is a temporary supporting structure and generally plays a role in the open cut stage, so in the foundation pit supporting design, the form of the enclosure structure is generally required to be considered by integrating the factors of the surrounding environment, the soil condition, the excavation depth of the foundation pit, the structure safety, the engineering cost, the construction convenience, the construction period and the like. For foundation pit engineering in a soft soil area within an excavation depth range of 5m, the enclosing structure form used in the existing supporting technology generally adopts the technologies of a cement soil gravity type enclosing wall, a section steel cement soil stirring wall, slope-laying excavation, inclined cast bracing supporting and the like.
The inclined cast support is characterized in that a central island is arranged at the bottom of a foundation pit, a crown beam is connected with the central island by adopting rod pieces such as steel pipes and profile steels, a soil body below the rod pieces is not excavated temporarily in the excavation process, the construction cost is low, and the influence on the surrounding environment is small.
In summary, the supporting mode of the shallow foundation pit is still not perfect, and most of the buildings at present build two-layer basements, which basically exceed the range of the shallow foundation pit, the scheme is not applicable any more, but the supporting mode commonly used for the deep foundation pit is adopted, so that the manufacturing cost is high, and the influence on the surrounding environment is large, therefore, the invention provides the construction method of the resistance-increasing large-deformation enclosure structure on the basis.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides a construction method of a resistance-increasing large-deformation envelope structure, and overcomes the defects in the prior art. The supporting rod of the traditional inclined throwing support is easy to try to cause buckling damage, the supporting rod is divided into a plurality of sections, the length of each section is reduced, and the yielding propeller and the yielding receiver are arranged, so that the length of the composite section of the supporting rod is increased, and the stability of the rod piece is improved; through the large deformation of the rod piece and the arrangement of the jack, the dynamic adjustment can be carried out at any time according to the supporting condition of the foundation pit, so that the instability of the rod piece is avoided; by adopting the vertical composite piles as the fender piles, the construction period is shortened compared with the traditional cast-in-place piles, the inclined composite piles replace central islands, later construction is not influenced, the construction efficiency is improved, and the bottom of each inclined strut is provided with an enlarged bottom bag, so that the anchoring force of the inclined strut is increased; vertical composite pile and diagonal brace are combined to form a triangular stable structure through the cushion layer, and the stability of the supporting structure is improved.
A construction method of a resistance-increasing large-deformation enclosure structure comprises an enlarged end head, a precast pile, a mixing pile, a cushion layer, an enlarged bottom bag, an inclined pile connecting key, a yielding resistance-increasing device, a jack, a vertical pile connecting key and a yielding support device; the yielding resistor comprises an axial force monitor, a yielding propeller, a yielding receiver and an expansion support; the yielding receiver comprises a receiver resistance increasing groove, a receiver outer wall and a receiver cavity; the yielding propeller comprises a propeller main body rod, a propeller expanding rod and a propeller protrusion key; the yielding support comprises a support side wall, a buffer damper and a yielding layer; the upper end and the lower end of the buffer damper are provided with annular damper supports; the precast pile and the mixing pile are combined into a composite pile, and the composite pile comprises two arrangement forms, namely a vertical composite pile arranged on the side wall and an oblique composite pile arranged at the bottom of the foundation pit; the enlarged end head is of a cuboid structure, and can effectively connect a plurality of precast piles and stirring piles in the horizontal direction; the stirring pile is of a cylindrical structure, the precast pile is arranged in the center of the stirring pile, and the diameter of the precast pile is smaller than that of the stirring pile; the vertical pile connecting key is connected with the enlarged end socket and the jack by bolts; the jack is connected with the yielding support through a bolt, and the yielding support is connected with the yielding resistor through scarf joint; the inclined pile connecting key is connected with the precast pile and the yielding resistance increasing device through bolts; the cushion layer is arranged at the bottom of the foundation pit and covers the surface of the oblique composite pile; the resistance increasing groove of the receiver is of a continuous annular concave structure, and the inner diameter of the cavity of the receiver is gradually reduced from one end of the enlarged support to the end far away from the enlarged support; the outer diameter of the side wall of the receiver is gradually increased from one end of the expanding support to the end far away from the expanding support; the propeller protruding key is in a semicircular convex shape, and the maximum diameter of the propeller protruding key is smaller than the maximum diameter of the receiver resistance-increasing groove and larger than the minimum diameter of the receiver resistance-increasing groove; the diameter of the propeller expanding rod is gradually increased from one end of the propeller main body rod to one end of the propeller protruding key, and the maximum diameter of the propeller expanding rod is smaller than that of the propeller protruding key; the damping support at the upper part of the buffer damping is connected with the side wall of the support in a welding mode, the damping support at the lower part of the buffer damping is embedded in the inner wall of the side wall of the support, the damping support at the lower part of the buffer damping is of an annular structure, and the outer diameter of the damping support is smaller than the inner diameter of the side wall of the support.
The method comprises the following steps: preparing and selecting a component;
the inner diameter of the cavity of the receiver is gradually reduced from one end of the enlarged support to the end far away from the enlarged support, the change is measured by adopting a slope, the range of the slope is 0-10%, the diameter of the body expanding rod of the propeller is gradually increased from one end of the body expanding rod of the propeller to one end of the protruding key of the propeller, the change is measured by adopting the slope, and the range of the slope is 0-6%; the method comprises the following steps of adjusting the gradient of the inner diameter of a cavity of a receiver, the gradient of the diameter of an expanding rod of a propeller and the damping coefficient of buffering damping according to the safety level of a foundation pit, wherein the range of the damping coefficient is 0-1:
when the safety level of the foundation pit is one level: the gradient of the inner diameter of the cavity of the receiver is 6-10%, the gradient of the diameter of the expanding rod of the propeller is 4-6%, and the damping coefficient of the buffer damper is 0.8-1.0;
when the safety level of the foundation pit is two levels: the gradient of the inner diameter of the cavity of the receiver is 3-6%, the gradient of the diameter of the expanding rod of the propeller is 2-4%, and the damping coefficient of the buffer damper is 0.5-0.8;
when the safety level of the foundation pit is three levels: the gradient of the inner diameter of the cavity of the receiver is 0-3%, the gradient of the diameter of the expanding rod of the propeller is 0-2%, and the damping coefficient of the buffer damper is 0.2-0.5;
step two: constructing a vertical composite pile;
adopting a stirring drilling machine to carry out stirring pile construction in the vertical composite pile, and adopting a pile pressing machine to implant the precast pile into the stirring pile within 1 hour after the stirring pile construction is finished;
step three: expanding end construction;
when the strength of the mixing pile reaches 50% -100% of the designed strength, removing the mixing pile with the top of the vertical composite pile within the range of 0.5m-2.0m, supporting a template within the removal range, and pouring an enlarged end material; before the initial setting of the material of the enlarged end head, inserting channel steel into the enlarged end head and fixing the channel steel, and arranging a bolt connecting port at the position where the channel steel extends out of the enlarged end head; if a plurality of vertical composite piles exist, horizontally connecting the plurality of vertical composite piles by adopting the enlarged end heads; when the enlarged end head reaches 75% of the designed compressive strength, the template is dismantled, and the channel steel fixing device is removed;
step four: excavating a foundation pit;
when the composite pile and the enlarged end reach 100% of the design strength, excavating a foundation pit soil body on one side of the vertical composite pile, wherein the side-excavated soil body cannot exceed the edge of the vertical composite pile, and when the excavation reaches 2 m-3 m, leveling the ground and preparing to construct an inclined composite pile;
step five: constructing an inclined pile structure;
will let in pressing propeller in propeller expansion body pole one end put into and let in pressing the receiver to the fixed receiver that lets, adopt 10t-30 t's top thrust will let and press the propeller and remove in letting presses the receiver, let and press the propeller and let and press the receiver to be connected qualified standard as follows: when the end part of the yielding propeller enters the 1/3 position of the length of the yielding receiver, and the jacking force is 25 t-30t, the connection is qualified; before the end of the yielding propeller enters the 1/3 position of the length of the yielding receiver, the connection is qualified when the 30t of top thrust cannot continuously push the yielding propeller to move in the yielding receiver;
mounting an axial force monitor at one end, far away from the propeller expanding rod, with a smaller diameter; penetrating the connected yielding propeller and yielding receiver through the side wall of the support to enable the enlarged support to be lapped on the yielding layer, connecting the buffer damping and the damping support through welding, and placing the buffer damping in the side wall of the support; enabling the axial force monitor and the propeller main body rod to penetrate through the buffer damper, enabling the axial force monitor to be connected with the jack through a bolt, enabling the buffer damper to be in a compression state, enabling the compression force to be 20% -40% of the maximum compression force of the buffer damper, and enabling the jack and one end, far away from the yielding layer, of the yielding support to be connected through a flange; hoisting an integral structure formed by combining the yielding resistance increasing device, the jack and the yielding support device by adopting a crane, adjusting the angle, fixing the enlarged bottom bag at the bottom of the precast pile, placing stones with set sizes into the enlarged bottom bag through a hollow hole in the middle of the precast pile, then sealing a direct interface between the enlarged bottom bag and the precast pile, connecting the yielding resistance increasing device with an inclined pile connecting key by adopting a bolt, and connecting the inclined pile connecting key with the precast pile in the inclined composite pile by adopting a bolt;
step six: constructing an oblique composite pile;
adopting a stirring drilling machine to carry out stirring pile construction in the oblique composite pile, implanting the connected oblique pile structure into the stirring pile, connecting the jack with the vertical pile connecting key by adopting a bolt when the oblique composite pile reaches 50-100% of the design strength, and connecting the vertical pile connecting key with the enlarged end head by adopting a bolt;
step seven: debugging the enclosure structure;
starting the jack, testing the stress state of each part of structure by pre-applying 10t-30t of pre-pressure, if the relative displacement between the yielding support and the yielding resistance increasing device is more than 10mm, readjusting the relative positions of the yielding resistance increasing device, the jack, the vertical pile connecting key and the yielding support to ensure that the yielding resistance increasing device, the jack, the vertical pile connecting key and the yielding support are stressed on the same axis, and if the relative displacement between the yielding support and the yielding resistance increasing device is less than or equal to 10mm, keeping the original state unchanged;
step eight: finishing construction;
after the main structure is installed, laying a cushion layer, wherein the thickness range of the cushion layer is 100mm-400 mm; and when the strength of the cushion layer reaches 100% of the design strength, starting the jack to load and set pre-pressure according to the design requirement, and finishing construction after ensuring that all the structures are cooperatively stressed according to the design requirement.
Preferably, in the fourth step, the stone block is placed into the enlarged bottom bag through a hollow hole in the middle of the precast pile, the bottom bag is in an inflated state after filling, the expanded diameter of the bottom bag is 20 cm-40 cm larger than the diameter of the precast pile, and then interface sealing treatment is performed, wherein the treatment technology is as follows: firstly, pouring fast-setting cement through a hollow hole in the middle of the precast pile to enable stones to be mutually cemented together, then pouring concrete, calculating the end, close to the enlarged bottom bag, of the precast pile, and filling the concrete into the hollow hole of the precast pile by 30 cm-50 cm.
Preferably, in the fifth step, the upper end face of the precast pile in the inclined pile structure is 20 cm-40 cm higher than the designed bottom face of the foundation pit.
Preferably, the cushion layer is laid in the seventh step, the cushion layer is of a reinforced concrete structure, the grade of concrete used for the cushion layer is C15-C25, and the diameter of the steel bars in the steel bar net in the cushion layer is 6 mm-10 mm.
The invention has the following beneficial technical effects:
the supporting rod of the traditional inclined throwing support is easy to try to cause buckling damage, the supporting rod is divided into a plurality of sections, the length of each section is reduced, and the yielding propeller and the yielding receiver are arranged, so that the length of the composite section of the supporting rod is increased, and the stability of the rod piece is improved; through the large deformation of the rod piece and the arrangement of the jack, the dynamic adjustment can be carried out at any time according to the supporting condition of the foundation pit, so that the instability of the rod piece is avoided; by adopting the vertical composite piles as the fender piles, the construction period is shortened compared with the traditional cast-in-place piles, the inclined composite piles replace central islands, later construction is not influenced, the construction efficiency is improved, and the bottom of each inclined strut is provided with an enlarged bottom bag, so that the anchoring force of the inclined strut is increased; vertical composite pile and diagonal brace are combined to form a triangular stable structure through the cushion layer, and the stability of the supporting structure is improved.
Drawings
Fig. 1 is a front view of a resistance-increasing large-deformation envelope and a construction method thereof.
Fig. 2 is a front view of a yielding resistor increasing device in the resistance increasing and large deformation envelope and the construction method thereof.
Fig. 3 is a front view of a yielding receiver in the resistance-increasing large-deformation envelope and the construction method thereof.
Fig. 4 is a front view of the end of the yielding thruster in the resistance-increasing large-deformation building envelope and the construction method thereof.
Fig. 5 is a front view of a yielding support in the resistance-increasing large-deformation envelope and the construction method thereof.
FIG. 6 is a front view of a damping buffer in the resistance-increasing large-deformation envelope and the construction method thereof of the present invention.
FIG. 7 is a top view of a damping support in the resistance-increasing large-deformation envelope and the construction method thereof of the present invention.
Wherein: 1-enlarged end, 2-precast pile, 3-mixing pile, 4-cushion layer, 5-enlarged bottom bag, 6-inclined pile connecting key, 7-yielding resistor increasing device, 8-jack, 9-vertical pile connecting key, 10-yielding support, 11-yielding propeller, 12-yielding receiver, 13-axial force monitor, 14-enlarged support, 15-receiver resistance increasing groove, 16-receiver side wall, 17-receiver cavity, 18-propeller main body rod, 19-propeller expansion rod, 20-propeller bulge key, 21-support side wall, 22-buffer damping, 23-yielding layer and 24-damping support.
Detailed Description
The invention is described in further detail below with reference to the following figures and detailed description:
example 1:
as shown in fig. 1 to 7, a construction method of a resistance-increasing large-deformation enclosure structure comprises an enlarged end 1, a precast pile 2, a mixing pile 3, a cushion layer 4, an enlarged bottom bag 5, an inclined pile connecting key 6, a yielding resistance-increasing device 7, a jack 8, a vertical pile connecting key 9 and a yielding support device 10; the yielding resistor 7 comprises an axial force monitor 13, a yielding propeller 11, a yielding receiver 12 and an expansion support 14; the yielding receiver 12 comprises a receiver resistance increasing groove 15, a receiver outer wall and a receiver cavity 17; the yielding propeller 11 comprises a propeller main body rod 18, a propeller expanding rod 19 and a propeller protruding key 20; the yielding support 10 comprises a support side wall 21, a buffer damper 22 and a yielding layer 23; the upper end and the lower end of the buffer damper 22 are provided with annular damper supports 24; the precast pile 2 and the mixing pile 3 are combined into a composite pile, and the composite pile comprises two arrangement forms, namely a vertical composite pile arranged on the side wall and an oblique composite pile arranged at the bottom of the foundation pit; the enlarged end 1 is of a cuboid structure, and the enlarged end 1 can be used for effectively connecting a plurality of precast piles 2 and stirring piles 3 in the horizontal direction; the stirring pile 3 is of a cylindrical structure, the precast pile 2 is arranged in the center of the stirring pile 3, and the diameter of the precast pile 2 is smaller than that of the stirring pile 3; the vertical pile connecting key 9 is connected with the enlarged end head 1 and the jack 8 through bolts; the jack 8 is connected with the yielding supporter 10 through a bolt, and the yielding supporter 10 is connected with the yielding resistor 7 through scarf joint; the inclined pile connecting key 6 is connected with the precast pile 2 and the yielding pressure increasing resistor 7 through bolts; the cushion layer 4 is arranged at the bottom of the foundation pit and covers the surface of the oblique composite pile; the receiver resistance-increasing groove 15 is of a continuous annular concave structure, and the inner diameter of the receiver cavity 17 is gradually reduced from one end of the enlarged support 14 to the end far away from the enlarged support 14; the outer diameter of the receiver side wall 16 gradually increases from one end of the enlarged support 14 to the end far away from the enlarged support 14; the propeller protruding key 20 is in a semicircular convex shape, and the maximum diameter of the propeller protruding key 20 is smaller than the maximum diameter of the receiver resistance-increasing groove 15 and larger than the minimum diameter of the receiver resistance-increasing groove 15; the diameter of the propeller expanding rod 19 is gradually increased from one end of the propeller main body rod 18 to one end of the propeller protruding key, and the maximum diameter of the propeller expanding rod 19 is smaller than that of the propeller protruding key 20; the damping support 24 at the upper part of the buffer damper 22 is connected with the support side wall 21 in a welding mode, the damping support 24 at the lower part of the buffer damper 22 is embedded in the inner wall of the support side wall 21, the damping support 24 at the lower part of the buffer damper 22 is of an annular structure, and the outer diameter of the damping support is smaller than the inner diameter of the support side wall 21, and the construction method is characterized by comprising the following steps:
the method comprises the following steps: preparing and selecting a component;
the inner diameter of the receiver cavity 17 is gradually reduced from one end of the enlarged support 14 to the end far away from the enlarged support 14, the change is measured by adopting a slope, the range of the slope is 0-10%, the diameter of the propeller expanding rod 19 is gradually increased from one end of the propeller main body rod 18 to one end of the propeller protruding key 20, the change is measured by adopting a slope, and the range of the slope is 0-6%; the method comprises the following steps of adjusting the gradient of the inner diameter of a receiver cavity 17, the gradient of the diameter of a propeller expanding rod 19 and the damping coefficient of a buffering damper 22 according to the safety level of a foundation pit, wherein the range of the damping coefficient is 0-1:
when the safety level of the foundation pit is one level: the gradient of the inner diameter of the receiver cavity 17 is 6-10%, the gradient of the diameter of the propeller expanding rod 19 is 4-6%, and the damping coefficient of the buffer damper 22 is 0.8-1.0;
when the safety level of the foundation pit is two levels: the gradient of the inner diameter of the receiver cavity 17 is 3% -6%, the gradient of the diameter of the propeller expanding rod 19 is 2% -4%, and the damping coefficient of the buffer damper 22 is 0.5-0.8;
when the safety level of the foundation pit is three levels: the gradient of the inner diameter of the receiver cavity 17 is 0-3%, the gradient of the diameter of the propeller expanding rod 19 is 0-2%, and the damping coefficient of the buffer damper 22 is 0.2-0.5;
step two: constructing a vertical composite pile;
adopting a stirring drilling machine to construct a stirring pile 3 in the vertical composite pile, and adopting a pile pressing machine to implant the precast pile 2 into the stirring pile 3 within 1 hour after the construction of the stirring pile 3 is completed;
step three: constructing an enlarged end 1;
when the strength of the mixing pile 3 reaches 50% -100% of the design strength, removing the mixing pile 3 with the top of the vertical composite pile within the range of 0.5m-2.0m, supporting a formwork within the removal range, and pouring an enlarged end head 1 material; before the material of the enlarged end head 1 is initially set, channel steel is inserted into the enlarged end head 1 and fixed, and a bolt connecting port is arranged at the position, extending out of the enlarged end head 1, of the channel steel; if a plurality of vertical composite piles exist, horizontally connecting the plurality of vertical composite piles by adopting the enlarged end heads 1; when the enlarged end 1 reaches 75% of the designed compressive strength, the template is dismantled, and the channel steel fixing device is removed;
step four: excavating a foundation pit;
when the composite pile and the enlarged end 1 reach 100% of the design strength, excavating a foundation pit soil body on one side of the vertical composite pile, wherein the laterally excavated soil body does not exceed the edge of the vertical composite pile, and when the excavation reaches 2 m-3 m, leveling the ground and preparing to construct an oblique composite pile;
step five: constructing an inclined pile structure;
one end of a propeller expanding rod 19 in the yielding propeller 11 is placed into the yielding receiver 12, the yielding receiver 12 is fixed, the yielding propeller 11 moves in the yielding receiver 12 by adopting the top thrust of 10t-30t, and the qualified standard of connection of the yielding propeller 11 and the yielding receiver 12 is as follows: when the end part of the yielding propeller 11 enters the 1/3 position of the length of the yielding receiver 12 and the jacking force is 25 t-30t, the connection is qualified; before the end of the yielding propeller 11 enters the 1/3 position of the length of the yielding receiver 12, the connection is qualified when the 30t top thrust cannot continuously push the yielding propeller 11 to move in the yielding receiver 12;
the axial force monitor is arranged at one end, far away from the propeller expanding rod 19, with the smaller diameter; penetrating the connected yielding thruster 11 and yielding receiver 12 through the side wall 21 of the support to enable the enlarged support 14 to be lapped on the yielding layer 23, connecting the buffer damper 22 with the damping support 24 through welding, and placing the buffer damper 22 in the side wall 21 of the support; the axial force monitor and the propeller main body rod 18 penetrate through the buffer damper 22, the axial force monitor is connected with the jack 8 through bolts, the buffer damper 22 is in a compression state, the compression force is 20% -40% of the maximum compression force of the buffer damper 22, and the jack 8 is connected with one end, far away from the yielding layer 23, of the yielding support 10 through a flange; hoisting an integral structure formed by combining the yielding resistance increasing device 7, the jack 8 and the yielding support device 10 by adopting a crane, adjusting the angle, fixing the enlarged bottom bag 5 at the bottom of the precast pile 2, placing a stone block with a set size into the enlarged bottom bag 5 through a hollow hole in the middle of the precast pile 2, then sealing a direct interface between the enlarged bottom bag 5 and the precast pile 2, connecting the yielding resistance increasing device 7 with the inclined pile connecting key 6 by adopting a bolt, and connecting the inclined pile connecting key 6 with the precast pile 2 in the inclined composite pile by adopting a bolt;
step six: constructing an oblique composite pile;
adopting a stirring drilling machine to construct a stirring pile 3 in the oblique composite pile, implanting the connected oblique pile structure into the stirring pile 3, connecting the jack 8 with the vertical pile connecting key 9 by adopting a bolt when the oblique composite pile reaches 50-100% of the designed strength, and connecting the vertical pile connecting key 9 with the enlarged end head 1 by adopting a bolt;
step seven: debugging the enclosure structure;
starting the jack 8, testing the stress state of each part of structure by pre-adding 10t-30t of pre-pressure, if the relative displacement between the yielding support 10 and the yielding resistor 7 is more than 10mm, readjusting the relative positions of the yielding resistor 7, the jack 8, the vertical pile connecting key 9 and the yielding support 10 to ensure that the yielding resistor 7, the jack 8, the vertical pile connecting key 9 and the yielding support 10 are stressed on the same axis, and if the relative displacement between the yielding support 10 and the yielding resistor 7 is less than or equal to 10mm, keeping the original state unchanged;
step eight: finishing construction;
after the main structure is installed, laying a cushion layer 4, wherein the thickness of the cushion layer 4 ranges from 100mm to 400 mm; and when the strength of the cushion layer 4 reaches 100% of the design strength, starting the jack 8 to load and set pre-pressure according to the design requirement, and finishing construction after ensuring that all the structures are cooperatively stressed according to the design requirement.
Preferably, in the fourth step, the stone block is placed into the expanded bottom bag 5 through the hollow hole in the middle of the precast pile 2, the bottom bag is in an inflated state after filling, the expanded diameter of the bottom bag is 20 cm-40 cm larger than the diameter of the precast pile 2, and then the interface is sealed, and the treatment technology is as follows: firstly, pouring fast-setting cement through the middle hollow hole of the precast pile 2 to enable stones to be mutually cemented together, then pouring concrete to the end, close to the enlarged bottom bag 5, of the precast pile 2, and filling the concrete into the hollow hole of the precast pile 2 by 30 cm-50 cm.
Preferably, in the fifth step, the upper end face of the precast pile 2 in the inclined pile structure is 20 cm-40 cm higher than the designed bottom face of the foundation pit.
Preferably, the cushion layer 4 is laid in the seventh step, the cushion layer 4 is of a reinforced concrete structure, the grade of concrete used for the cushion layer 4 is C15-C25, and the diameter of the steel bars in the steel bar net in the cushion layer 4 is 6 mm-10 mm.
The invention relates to a resistance-increasing large-deformation enclosure structure and a construction method thereof.A supporting rod of a traditional inclined throwing support is easy to try buckling damage; through the large deformation of the rod piece and the arrangement of the jack, the dynamic adjustment can be carried out at any time according to the supporting condition of the foundation pit, so that the instability of the rod piece is avoided; by adopting the vertical composite piles as the fender piles, the construction period is shortened compared with the traditional cast-in-place piles, the inclined composite piles replace central islands, later construction is not influenced, the construction efficiency is improved, and the bottom of each inclined strut is provided with an enlarged bottom bag, so that the anchoring force of the inclined strut is increased; vertical composite pile and diagonal brace are combined to form a triangular stable structure through the cushion layer, and the stability of the supporting structure is improved.
It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make modifications, alterations, additions or substitutions within the spirit and scope of the present invention.
Claims (4)
1. A construction method of a resistance-increasing large-deformation enclosure structure comprises an enlarged end head, a precast pile, a mixing pile, a cushion layer, an enlarged bottom bag, an inclined pile connecting key, a yielding resistance-increasing device, a jack, a vertical pile connecting key and a yielding support device; the yielding resistor comprises an axial force monitor, a yielding propeller, a yielding receiver and an expansion support; the yielding receiver comprises a receiver resistance increasing groove, a receiver outer wall and a receiver cavity; the yielding propeller comprises a propeller main body rod, a propeller expanding rod and a propeller protrusion key; the yielding support comprises a support side wall, a buffer damper and a yielding layer; the upper end and the lower end of the buffer damper are provided with annular damper supports; the precast pile and the mixing pile are combined into a composite pile, and the composite pile comprises two arrangement forms, namely a vertical composite pile arranged on the side wall and an oblique composite pile arranged at the bottom of the foundation pit; the enlarged end head is of a cuboid structure, and can effectively connect a plurality of precast piles and stirring piles in the horizontal direction; the stirring pile is of a cylindrical structure, the precast pile is arranged in the center of the stirring pile, and the diameter of the precast pile is smaller than that of the stirring pile; the vertical pile connecting key is connected with the enlarged end socket and the jack through bolts; the jack is connected with the yielding support through a bolt, and the yielding support is connected with the yielding resistor through scarf joint; the inclined pile connecting key is connected with the precast pile and the yielding resistance increasing device through bolts; the cushion layer is arranged at the bottom of the foundation pit and covers the surface of the oblique composite pile; the resistance increasing groove of the receiver is of a continuous annular concave structure, and the inner diameter of the cavity of the receiver is gradually reduced from one end of the enlarged support to the end far away from the enlarged support; the outer diameter of the side wall of the receiver is gradually increased from one end of the expanding support to the end far away from the expanding support; the propeller protruding key is in a semicircular convex shape, and the maximum diameter of the propeller protruding key is smaller than the maximum diameter of the receiver resistance-increasing groove and larger than the minimum diameter of the receiver resistance-increasing groove; the diameter of the propeller expanding rod is gradually increased from one end of the propeller main body rod to one end of the propeller protruding key, and the maximum diameter of the propeller expanding rod is smaller than that of the propeller protruding key; the damping support at the upper part of the buffer damping is connected with the side wall of the support in a welding mode, the damping support at the lower part of the buffer damping is embedded in the inner wall of the side wall of the support, the damping support at the lower part of the buffer damping is of an annular structure, and the outer diameter of the damping support is smaller than the inner diameter of the side wall of the support.
The method comprises the following steps: preparing and selecting a component;
the inner diameter of the cavity of the receiver is gradually reduced from one end of the enlarged support to the end far away from the enlarged support, the change is measured by adopting a slope, the range of the slope is 0-10%, the diameter of the body expanding rod of the propeller is gradually increased from one end of the body expanding rod of the propeller to one end of the protruding key of the propeller, the change is measured by adopting the slope, and the range of the slope is 0-6%; the method comprises the following steps of adjusting the gradient of the inner diameter of a cavity of a receiver, the gradient of the diameter of an expanding rod of a propeller and the damping coefficient of buffering damping according to the safety level of a foundation pit, wherein the range of the damping coefficient is 0-1:
when the safety level of the foundation pit is one grade: the gradient of the inner diameter of the cavity of the receiver is 6-10%, the gradient of the diameter of the expanding rod of the propeller is 4-6%, and the damping coefficient of the buffer damper is 0.8-1.0;
when the safety level of the foundation pit is two levels: the gradient of the inner diameter of the cavity of the receiver is 3% -6%, the gradient of the diameter of the expanding rod of the propeller is 2% -4%, and the damping coefficient of the buffer damping is 0.5-0.8;
when the safety level of the foundation pit is three levels: the gradient of the inner diameter of the cavity of the receiver is 0-3%, the gradient of the diameter of the expanding rod of the propeller is 0-2%, and the damping coefficient of the buffer damper is 0.2-0.5;
step two: constructing a vertical composite pile;
adopting a stirring drilling machine to carry out stirring pile construction in the vertical composite pile, and adopting a pile pressing machine to implant the precast pile into the stirring pile within 1 hour after the stirring pile construction is finished;
step three: expanding end construction;
when the strength of the mixing pile reaches 50% -100% of the design strength, removing the mixing pile with the top of the vertical composite pile within the range of 0.5-2.0 m, supporting a formwork within the removal range, and pouring an enlarged end material; before the initial setting of the material of the enlarged end head, inserting channel steel into the enlarged end head and fixing the channel steel, and arranging a bolt connecting port at the position where the channel steel extends out of the enlarged end head; if a plurality of vertical composite piles exist, horizontally connecting the plurality of vertical composite piles by adopting the enlarged end heads; when the enlarged end head reaches 75% of the designed compressive strength, the template is dismantled, and the channel steel fixing device is removed;
step four: excavating a foundation pit;
when the composite pile and the enlarged end head reach 100% of the design strength, excavating a foundation pit soil body on one side of the vertical composite pile, wherein the laterally excavated soil body does not exceed the edge of the vertical composite pile, and when the excavation reaches 2 m-3 m, leveling the ground and preparing to construct an oblique composite pile;
step five: constructing an inclined pile structure;
will let in pressing propeller in propeller expansion body pole one end put into and let in pressing the receiver to the fixed receiver that lets, adopt 10t-30 t's top thrust will let and press the propeller and remove in letting presses the receiver, let and press the propeller and let and press the receiver to be connected qualified standard as follows: when the end part of the yielding propeller enters the 1/3 position of the length of the yielding receiver and the jacking force is 25 t-30t, connecting; when the end of the yielding propeller enters the 1/3 position of the length of the yielding receiver, the 30t top thrust cannot continuously push the yielding propeller to be connected when the yielding propeller moves in the yielding receiver;
mounting an axial force monitor at one end, far away from the propeller expanding rod, with a smaller diameter; penetrating the connected yielding propeller and yielding receiver through the side wall of the support to enable the enlarged support to be lapped on the yielding layer, connecting the buffer damping and the damping support through welding, and placing the buffer damping in the side wall of the support; the axial force monitor and the propeller main body rod penetrate through the buffer damper, the axial force monitor is connected with the jack through a bolt, the buffer damper is in a compression state, the compression force is 20% -40% of the maximum compression force of the buffer damper, and the jack is connected with one end, away from the yielding layer, of the yielding supporter through a flange; hoisting an integral structure formed by combining the yielding resistance increasing device, the jack and the yielding support device by adopting a crane, adjusting the angle, fixing the enlarged bottom bag at the bottom of the precast pile, placing a stone block with a set size into the enlarged bottom bag through a hollow hole in the middle of the precast pile, then sealing a direct interface between the enlarged bottom bag and the precast pile, connecting the yielding resistance increasing device with an inclined pile connecting key by adopting a bolt, and connecting the inclined pile connecting key with the precast pile in the inclined composite pile by adopting a bolt;
step six: constructing an oblique composite pile;
adopting a stirring drilling machine to carry out stirring pile construction in the oblique composite pile, implanting the connected oblique pile structure into the stirring pile, connecting the jack with the vertical pile connecting key by adopting a bolt when the oblique composite pile reaches 50-100% of the design strength, and connecting the vertical pile connecting key with the enlarged end head by adopting a bolt;
step seven: debugging the enclosure structure;
starting a jack, testing the stress state of each part of structure by pre-applying 10t-30t of pre-pressure, if the relative displacement between the yielding pressure support and the yielding pressure increasing device is more than 10mm, readjusting the relative positions of the yielding pressure increasing device, the jack, the vertical pile connecting key and the yielding pressure support to ensure that the yielding pressure increasing device, the jack, the vertical pile connecting key and the yielding pressure support are stressed on the same axis, and if the relative displacement between the yielding pressure support and the yielding pressure increasing device is less than or equal to 10mm, keeping the original state unchanged;
step eight: finishing construction;
after the main structure is installed, laying a cushion layer, wherein the thickness range of the cushion layer is 100mm-400 mm; and when the strength of the cushion layer reaches 100% of the design strength, starting the jack to load and set pre-pressure according to the design requirement, and finishing construction after ensuring that all the structures are cooperatively stressed according to the design requirement.
2. The construction method of a resistance-increasing large-deformation building envelope according to claim 1, wherein in the fifth step, the stone blocks are put into the enlarged bottom bag through the hollow hole in the middle of the precast pile, the bottom bag is in an inflated state after filling, the expanded diameter of the bottom bag is 20cm to 40cm larger than the diameter of the precast pile, and then the interface is sealed, and the treatment technology is as follows: firstly, pouring fast setting cement through a hollow hole in the middle of the precast pile to enable stones to be mutually cemented together, then pouring concrete, and filling the concrete to the position, close to one end of the expanded bottom bag, of the precast pile until the concrete is filled into the hollow hole of the precast pile for 30-50 cm.
3. The construction method of the resistance-increasing large-deformation enclosure structure according to claim 1, wherein in the sixth step, the upper end face of the precast pile in the inclined pile structure is 20cm to 40cm higher than the designed bottom face of the foundation pit.
4. The construction method of a resistance-increasing large-deformation envelope structure as claimed in claim 1, wherein in the eighth step, a cushion layer is laid, the cushion layer is of a reinforced concrete structure, the concrete grade of the cushion layer is C15-C25, and the diameter of the steel bars in the steel bar net in the cushion layer is 6 mm-10 mm.
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