CN110820763A - Truss type cast-in-situ bored pile supporting method for mucky soil deep foundation pit - Google Patents

Truss type cast-in-situ bored pile supporting method for mucky soil deep foundation pit Download PDF

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Publication number
CN110820763A
CN110820763A CN201911206429.5A CN201911206429A CN110820763A CN 110820763 A CN110820763 A CN 110820763A CN 201911206429 A CN201911206429 A CN 201911206429A CN 110820763 A CN110820763 A CN 110820763A
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Prior art keywords
piles
pile
row
soil
foundation pit
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CN201911206429.5A
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Inventor
程选生
李小双
李文惠
巩利军
张万林
张淑娟
刘华东
陈俭超
张尚龙
杨莉萍
刘殷君
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Lanzhou University of Technology
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Lanzhou University of Technology
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Priority to CN201911206429.5A priority Critical patent/CN110820763A/en
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Pending legal-status Critical Current

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    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D17/00Excavations; Bordering of excavations; Making embankments
    • E02D17/02Foundation pits
    • E02D17/04Bordering surfacing or stiffening the sides of foundation pits
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D19/00Keeping dry foundation sites or other areas in the ground
    • E02D19/06Restraining of underground water
    • E02D19/12Restraining of underground water by damming or interrupting the passage of underground water
    • E02D19/18Restraining of underground water by damming or interrupting the passage of underground water by making use of sealing aprons, e.g. diaphragms made from bituminous or clay material
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/18Bulkheads or similar walls made solely of concrete in situ
    • E02D5/187Bulkheads or similar walls made solely of concrete in situ the bulkheads or walls being made continuously, e.g. excavating and constructing bulkheads or walls in the same process, without joints
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/74Means for anchoring structural elements or bulkheads
    • E02D5/76Anchorings for bulkheads or sections thereof in as much as specially adapted therefor
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D2250/00Production methods
    • E02D2250/0046Production methods using prestressing techniques
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D2600/00Miscellaneous
    • E02D2600/30Miscellaneous comprising anchoring details

Abstract

The invention discloses a truss type cast-in-situ bored pile supporting method for a muddy soil deep foundation pit, which relates to the field of deep foundation pit supporting, and the method is mainly characterized in that a mechanical calculation model is established, the supporting structure is simplified and the safety requirement is met at the same time; meanwhile, the mutual action of the front row of piles and the rear row of piles is utilized, the displacement of the structure is reduced, and the overall stability of the structure is improved.

Description

Truss type cast-in-situ bored pile supporting method for mucky soil deep foundation pit
Technical Field
The invention relates to the technical field of deep foundation pit supporting, in particular to a method for supporting a truss type cast-in-situ bored pile of a muddy soil deep foundation pit.
Background
With the rapid development of economy in China and the continuous promotion of urbanization construction, higher requirements are put forward on the design of buildings, the underground space of the buildings is required to be fully utilized, and a plurality of deep foundation pit supporting projects are generated. Due to the restriction of geological conditions, the dense buildings and the complex situation around the building site, the traditional foundation pit excavation method is restricted, and a safer and more reliable supporting mode is needed.
Mucky soil is widely distributed in China, serious potential safety hazards are caused to the excavation of deep foundation pits, and in order to increase the construction safety, the area to be excavated needs to be supported before excavation. At present, the main supporting methods include the following methods: deep mixing pile support, steel sheet pile wall support, reinforced concrete row pile support and underground continuous wall support. However, all four support methods have certain defects: the deep mixing pile supports, the strength of the pile body structure is too low, the stability is lacked, and large displacement deformation occurs under the condition of too poor geological conditions, so that the foundation pit is easy to be unstable; in the process of steel sheet pile wall support, a large field is required and enough construction space is required; the construction may cause the deformation of the foundation of the adjacent building and the generation of vibration noise, and has great influence on the nearby environment, which is not in accordance with the civilized construction requirement advocated by the state, and the support depth is limited, and the depth is increased, so that the structure has great deformation; compared with other methods, the reinforced concrete row pile support takes long time, is not suitable for soil layers with poor geological conditions, can not deeply form a foundation pit, and can cause integral instability due to the damage of a certain node of the structure; the underground continuous wall support has the disadvantages of complex construction process, difficult control of the engineering quality of wall joints, high construction technical requirement, high cost and complex post-treatment.
Disclosure of Invention
In order to solve the problems, the invention provides a truss type cast-in-situ bored pile supporting method for a muddy soil deep foundation pit, which optimizes the cost, the effect and the time.
The invention provides a truss type cast-in-situ bored pile supporting method for a mucky soil deep foundation pit, which comprises the following steps of:
s1, selecting proper diameter of the cast-in-situ bored pile, size of the crown beam, pile spacing, row spacing of the pile and insertion depth of the pile, calculating stress of the structure according to the calculation model, and finally providing reinforcement of the structure;
s2, leveling the top surface of a foundation pit of the excavation site of the building, excavating a side slope with proper height according to a specified slope-releasing proportion, then post-treating foundation soil or directly treating the foundation soil without releasing the slope, and driving a steel plate or a wall body at a proper position above the side slope or at a proper position of a back row pile to be used as a water baffle;
s3, constructing a rear row of reinforcing piles and a front row of supporting piles by adopting a drilling and pouring method, wherein the distance between the front row of piles is twice that of the rear row of piles;
s4, forming a concrete wall between the front piles in the form of jet grouting piles to play a role of a waterproof curtain;
s5, hardening the mucky soil layer between the front row of piles and the rear row of piles;
s6, binding the front row pile crown beam and the rear row pile crown beam with the configuration steel bars, then binding the configuration steel bars of the web member coupling beam, and finally binding the configuration steel bars of the diagonal member coupling beam 9, and pouring concrete after the binding of the steel bars is finished to form a system;
s7, after the strength of the supporting structure reaches the standard, dewatering the foundation pit, and gradually excavating the foundation pit after the dewatering is finished; when anchor cables need to be added, holes are drilled in the centers of the row pile intervals, steel strands are driven into the holes, concrete is poured into the holes, wedge-shaped cushion blocks and two channel steel are used for supporting the surfaces of the waterproof curtains, the steel strands are stretched by using anchorage devices and are fixed by using clamps and gaskets, then the prestressed anchor cables are formed, the steel strands are excavated to the required depth, and engineering construction is carried out after the bottom surface of a foundation pit is treated;
and S8, monitoring the lateral movement of the supporting structure after the excavation reaches the excavation depth.
Further, the method also comprises the process of establishing and verifying the calculation model, and the specific steps are as follows:
s9, simplifying the piles and the beams into a portal rigid frame form, simplifying anchor rods into sliding hinged supports, simplifying pile bottoms into rigid connection, establishing a calculation model, and enabling the depth of a foundation pit to be h and the embedding depth of the piles to be hl d The row pitch of the piles islThe passive earth pressure isp s0 The center distance between the piles in the front row isb 0 The active earth pressure isp ak Then, analyzing the stress and displacement conditions of the structure by using a calculation model;
s10, determining the stress of the calculation model according to the information of the soil layer obtained by exploration, calculating the rigidity of the front row of piles and the connecting beams by twice, and calculating the internal force and the displacement of the rod piece;
and S11, calculating the reinforcing bars of each rod piece according to the internal force obtained in the step S10, and taking the calculated design values of the front row piles, the connecting beams and the anchor bolts as a half of the maximum internal force calculated in the step S10 according to a simplified calculation model.
S12, carrying out the following checking calculation on the calculation result to ensure the stability of the structure:
s12, carrying out the following checking calculation on the calculation result to ensure the stability of the structure:
(a) the maximum lateral movement of the inner side of the foundation pit after the excavation is finished is checked and calculated by the formula (1):
(1)
(b) and (3) checking the overall stability of the double-row pile supporting structure by adopting a Swedish segmentation method, wherein a checking formula (2) is as follows:
(2)
(c) and (3) checking the anti-overturning stability of the double-row pile supporting structure, wherein a checking formula (3) is as follows:
(3)
in the formula:maximum lateral movement of the finger structure;refers to the maximum lateral movement of the structure allowed;indicating a safety factor;respectively indicating the cohesive force on the arc surface of the ith soil strip in unit of kPa, the width of the ith soil strip in unit of m;the included angle of the normal line at the middle point of the arc surface of the ith soil strip and the vertical plane is unit degree;the length of the arc of the ith soil strip is taken in the unit of mThe standard value of the additional distributed load on the ith soil strip is expressed in unit of kPa; the self weight of the ith soil strip is calculated according to the natural gravity in kN unit;the unit is the water pressure on the arc surface of the ith soil strip, and the unit is kPa;the resultant force of the passive soil pressure is expressed in kN;the distance from the resultant force of the passive soil pressure to the pile bottom is expressed in m;the fulcrum force at the ith point is expressed in kN;the distance from the fulcrum force of the ith point to the pile bottom is expressed in m;the resultant force of the active soil pressure is expressed in kN;the distance from the resultant force of the active soil pressure to the pile bottom is expressed in m.
The invention has the beneficial effects that:
according to the truss type cast-in-situ bored pile supporting method for the mucky soil deep foundation pit, disclosed by the invention, the construction method is improved, the process is simplified, the cost is reduced, the time is shortened, and the structure achieves the effect of the original supporting structure; compared with the traditional supporting structure, the waterproof curtain is formed by the jet grouting piles, the number of the rear row piles is reduced, the structure is connected into a whole in a space truss mode, the engineering quantity is reduced, the engineering construction time is shortened, the engineering cost is reduced, and the maximum benefit is achieved; meanwhile, the mutual action of the front row of piles and the rear row of piles is utilized, the displacement of the structure is reduced, and the overall stability of the structure is improved.
Drawings
FIG. 1 is a schematic plan view of a method for supporting a truss type cast-in-situ bored pile of a muddy soil deep foundation pit;
FIG. 2 is a schematic elevation view of a method for supporting a truss type cast-in-situ bored pile in a muddy soil deep foundation pit;
FIG. 3 is a schematic cross-sectional view of a method for supporting a truss-type cast-in-situ bored pile of a muddy soil deep foundation pit;
FIG. 4 is a schematic diagram of a calculation model of a truss type cast-in-situ bored pile supporting method for a muddy soil deep foundation pit.
Reference numerals: 1 is a rear row reinforced pile, 2 is a front row support pile, 3 is a jet grouting pile, 5 is a mucky soil layer, 6 is a front row pile crown beam, 7 is a rear row pile crown beam, 8 is a web member connecting beam, 9 is an inclined rod connecting beam, 10 is a prestressed anchor cable, 11 is a steel strand, 12 is a wedge-shaped cushion block, 13 is a channel steel, 14 is a clamp, 15 is a gasket, and h is the depth of a foundation pit,l d the depth of the embedded pile is the depth of the embedded pile,lthe row pitch of the piles is set as the pitch,p s0 in order to be subject to the earth pressure,b 0 is the center distance between the piles in the front row,p ak active earth pressure.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Examples
Referring to fig. 1 to 4, as shown in fig. 1 to 4, the present invention provides a method for supporting a truss-type cast-in-situ bored pile of a muddy soil deep foundation pit, and the present invention provides a method for supporting a truss-type cast-in-situ bored pile of a muddy soil deep foundation pit, including the steps of:
s1, selecting proper diameter of the cast-in-situ bored pile, size of the crown beam, pile spacing, row spacing of the pile and insertion depth of the pile, calculating stress of the structure according to the calculation model, and finally providing reinforcement of the structure;
s2, leveling the top surface of a foundation pit of the excavation site of the building, excavating a side slope with proper height according to a specified slope-releasing proportion, then post-treating foundation soil or directly treating the foundation soil without releasing the slope, and driving a steel plate or a wall body at a proper position above the side slope or at a proper position of a back row pile to be used as a water baffle;
s3, constructing the rear row reinforcing piles 1 and the front row supporting piles 2 by adopting a drilling and pouring method, wherein the distance between the front row piles is twice that of the rear row piles;
s4, forming a concrete wall between the front row of piles in the form of the jet grouting piles 3 to play a role of a waterproof curtain;
s5, hardening the mucky soil layer 5 between the front row of piles and the rear row of piles;
s6, binding the configuration reinforcing steel bars of the front row of pile crown beams 6 and the rear row of pile crown beams 7, binding the configuration reinforcing steel bars of the web member coupling beams 8, binding the configuration reinforcing steel bars of the diagonal member coupling beams 9, and pouring concrete after binding the reinforcing steel bars to form a system;
s7, after the strength of the supporting structure reaches the standard, dewatering the foundation pit, and gradually excavating the foundation pit after the dewatering is finished; when anchor cables need to be added, holes are drilled in the centers of the row pile intervals, steel strands 11 are driven into the holes and then concrete is poured, wedge-shaped cushion blocks 12 and two channel steel 13 are used for supporting the surface of a waterproof curtain, the steel strands are stretched by using anchorage devices and are fixed by using clamps 14 and gaskets 15, then prestressed anchor cables 10 are formed, the excavation is carried out to the required depth, and engineering construction is carried out after the bottom surface of a foundation pit is treated;
and S8, monitoring the lateral movement of the supporting structure after the excavation reaches the excavation depth.
The method also comprises the process of establishing and verifying the calculation model, and the specific steps are as follows:
s9, adopting the structure in FIG 1 as a calculation unit, simplifying piles and beams into a portal rigid frame form, simplifying anchor rods into sliding hinged supports, simplifying pile bottoms into rigid connection, establishing a calculation model, and enabling the depth of a foundation pit to be h and the embedment depth of the piles to be hl d The row pitch of the piles islThe passive earth pressure isp s0 Front row ofThe center distance between piles isb 0 The active earth pressure isp ak
See fig. 4, and analyzing the stress and displacement conditions of the structure by using a calculation model;
s10, determining the stress of the calculation model according to the information of the soil layer obtained by exploration, calculating the rigidity of the front row of piles and the connecting beams by twice, and calculating the internal force and the displacement of the rod piece;
and S11, calculating the reinforcing bars of each rod piece according to the internal force obtained in the step S10, and taking the calculated design values of the front row piles, the connecting beams and the anchor bolts as a half of the maximum internal force calculated in the step S10 according to a simplified calculation model.
S12, carrying out the following checking calculation on the calculation result to ensure the stability of the structure:
(a) the maximum lateral movement of the inner side of the foundation pit after the excavation is finished is checked and calculated by the formula (1):
(1)
(b) and (3) checking the overall stability of the double-row pile supporting structure by adopting a Swedish segmentation method, wherein a checking formula (2) is as follows:
(2)
(c) and (3) checking the anti-overturning stability of the double-row pile supporting structure, wherein a checking formula (3) is as follows:
(3)
in the formula:maximum lateral movement of the finger structure;refers to the maximum lateral movement of the structure allowed;indicating a safety factor;respectively indicating the cohesive force on the arc surface of the ith soil strip in unit of kPa, the width of the ith soil strip in unit of m;the included angle of the normal line at the middle point of the arc surface of the ith soil strip and the vertical plane is unit degree;the length of the arc of the ith soil strip is taken in the unit of mThe standard value of the additional distributed load on the ith soil strip is expressed in unit of kPa; the self weight of the ith soil strip is calculated according to the natural gravity in kN unit;the unit is the water pressure on the arc surface of the ith soil strip, and the unit is kPa;the resultant force of the passive soil pressure is expressed in kN;the distance from the resultant force of the passive soil pressure to the pile bottom is expressed in m;the fulcrum force at the ith point is expressed in kN;the distance from the fulcrum force of the ith point to the pile bottom is expressed in m;the resultant force of the active soil pressure is expressed in kN;the distance from the resultant force of the active soil pressure to the pile bottom is expressed in m.
Examples of the experiments
The excavation depth h of the existing foundation pit with certain mucky soil is 7m, and the result of geological exploration is that ① miscellaneous filling soil is 5m in thickness and 11kN/m in gravity34kPa cohesive force and 10 degrees internal friction angle, ② mucky soil with thickness of 5m and gravity of 18kN/m3The cohesive force is 9kPa, the internal friction angle is 9 degrees, and the buoyancy is 8kN/m3With underwater cohesive force of 9kPa and underwater internal friction angle of 3 degrees, ③ crushed stones with a thickness of 20m and a gravity of 20kN/m3The superficial gravity is 10kN/m3The underwater cohesive force is 30kPa, the underwater internal friction angle is 30 degrees, soil layers below ④ are rock strata, the safety level of a foundation pit is one grade, and the depth of internal and external precipitation is 10 m.
The diameter of the selected front and rear concrete cast-in-place piles is 0.8m, the distance between the front row of piles is 1.6m, the distance between the rear row of piles is 3.2m, the row distance between the front row of piles and the rear row of piles is 2.4m, and the sizes of the front and rear crown beams and the coupling beams are as followsC35 grade concrete is adopted, the embedding depth is 5m, and a pull anchor is respectively arranged at the depths of 1m, 3m and 5 m. And determining the internal force and the displacement according to the calculation model, and carrying out structural design.
Checking and calculating the maximum lateral movement of the inner side of the foundation pit after the excavation is finished: the safety grade of foundation ditch is one-level, and the biggest sidesway of allowing is 0.0025h, and the biggest sidesway of the inboard foundation ditch of calculation model is 1mm, promptly:
meets the requirements.
The overall stability of the design structure is checked, a Swedish segmentation method is adopted, the radius R =9.695m of the circular arc, the center coordinates X = -0.061m and Y =4.130m, and the width of the soil bar is 1m, namely:
total friction force
Total cohesion force
Total sliding force
When the security level is one grade,K u1taking 1.350, namely:
the skid resistance of the foundation pit meets the requirements.
And (3) checking and calculating the anti-overturning stability of the designed supporting structure:
the bending moment of the resultant force of the passive soil pressure to the pile bottom is as follows:
the sum of the bending moments of the pile bottoms by the force of each fulcrum is as follows:
the bending moment of the resultant force of the active soil pressure to the pile bottom is as follows:
securityWhen the grade is one grade, Ku2Taking 1.250, namely:
the anti-overturning performance of the foundation pit meets the requirement.
According to the truss type cast-in-situ bored pile supporting method for the mucky soil deep foundation pit, disclosed by the invention, the construction method is improved, the process is simplified, the cost is reduced, the time is shortened, and the structure achieves the effect of the original supporting structure; compared with the traditional supporting structure, the waterproof curtain is formed by the jet grouting piles, the number of the rear row piles is reduced, the structure is connected into a whole in a space truss mode, the engineering quantity is reduced, the engineering construction time is shortened, the engineering cost is reduced, and the maximum benefit is achieved; meanwhile, the mutual action of the front row of piles and the rear row of piles is utilized, the displacement of the structure is reduced, and the overall stability of the structure is improved.
In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (2)

1. A truss type cast-in-situ bored pile supporting method for a mucky soil deep foundation pit is characterized by comprising the following steps:
s1, selecting proper diameter of the cast-in-situ bored pile, size of the crown beam, pile spacing, row spacing of the pile and insertion depth of the pile, calculating stress of the structure according to the calculation model, and finally providing reinforcement of the structure;
s2, leveling the top surface of a foundation pit of the excavation site of the building, excavating a side slope with proper height according to a specified slope-releasing proportion, then post-treating foundation soil or directly treating the foundation soil without releasing the slope, and driving a steel plate or a wall body at a proper position above the side slope or at a proper position of a back row pile to be used as a water baffle;
s3, constructing the rear row reinforcing piles (1) and the front row supporting piles (2) by adopting a drilling and pouring method, wherein the distance between the front row piles is twice that of the rear row piles;
s4, forming a concrete wall between the front row of piles in the form of the jet grouting piles (3) to play a role of a waterproof curtain;
s5, hardening the mucky soil layer (5) between the front row of piles and the rear row of piles;
s6, binding the configuration reinforcing steel bars of the front row of pile crown beams (6) and the rear row of pile crown beams (7) respectively for the front and rear crown beams and the connecting beam formwork, then binding the configuration reinforcing steel bars of the web member connecting beam (8), finally binding the configuration reinforcing steel bars of the diagonal member connecting beam (9), and pouring concrete after the binding of the reinforcing steel bars is finished to form a system;
s7, after the strength of the supporting structure reaches the standard, dewatering the foundation pit, and gradually excavating the foundation pit after the dewatering is finished; when anchor cables need to be added, holes are drilled in the centers of the row pile intervals, steel strands (11) are driven into the holes and then concrete is poured, wedge-shaped cushion blocks (12) and two channel steel (13) are used for supporting the surfaces of the waterproof curtains, then the steel strands are stretched by using anchorage devices and are fixed by using clamps (14) and gaskets (15), then prestressed anchor cables (10) are formed, the steel strands are excavated to the required depth, and engineering construction is carried out after the bottom surface of a foundation pit is treated;
and S8, monitoring the lateral movement of the supporting structure after the excavation reaches the excavation depth.
2. The truss type cast-in-situ bored pile support method for the mucky soil deep foundation pit according to claim 1, further comprising the steps of establishing and verifying a calculation model, and specifically comprising the steps of:
s9, simplifying the piles and the beams into a portal rigid frame form, simplifying anchor rods into sliding hinged supports, simplifying pile bottoms into rigid connection, establishing a calculation model, and enabling the depth of a foundation pit to be h and the embedding depth of the piles to be hl d The row pitch of the piles islThe passive earth pressure isp s0 The center distance between the piles in the front row isb 0 The active earth pressure isp ak Then analyzing the junction with a computational modelThe force and displacement of the structure;
s10, determining the stress of the calculation model according to the information of the soil layer obtained by exploration, calculating the rigidity of the front row of piles and the connecting beams by twice, and calculating the internal force and the displacement of the rod piece;
s11, calculating the reinforcing bars of all the rod pieces according to the internal force obtained in the step S10, and taking the calculated design values of the front row piles, the connecting beams and the anchor blocks as a half of the maximum internal force calculated in the step S10 according to a simplified calculation model;
s12, carrying out the following checking calculation on the calculation result to ensure the stability of the structure:
(a) the maximum lateral movement of the inner side of the foundation pit after the excavation is finished is checked and calculated by the formula (1):
(1)
(b) and (3) checking the overall stability of the double-row pile supporting structure by adopting a Swedish segmentation method, wherein a checking formula (2) is as follows:
(2)
(c) and (3) checking the anti-overturning stability of the double-row pile supporting structure, wherein a checking formula (3) is as follows:
(3)
in the formula:maximum lateral movement of the finger structure;refers to the maximum lateral movement of the structure allowed;indicating a safety factor;respectively indicating the cohesive force on the arc surface of the ith soil strip in unit of kPa, the width of the ith soil strip in unit of m;the included angle of the normal line at the middle point of the arc surface of the ith soil strip and the vertical plane is unit degree;the length of the arc of the ith soil strip is taken in the unit of mThe standard value of the additional distributed load on the ith soil strip is expressed in unit of kPa; the self weight of the ith soil strip is calculated according to the natural gravity in kN unit;the unit is the water pressure on the arc surface of the ith soil strip, and the unit is kPa;the resultant force of the passive soil pressure is expressed in kN;the distance from the resultant force of the passive soil pressure to the pile bottom is expressed in m;the fulcrum force at the ith point is expressed in kN;the distance from the fulcrum force of the ith point to the pile bottom is expressed in m;the resultant force of the active soil pressure is expressed in kN;the distance from the resultant force of the active soil pressure to the pile bottom is expressed in m.
CN201911206429.5A 2019-11-29 2019-11-29 Truss type cast-in-situ bored pile supporting method for mucky soil deep foundation pit Pending CN110820763A (en)

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CN113605397A (en) * 2021-07-14 2021-11-05 广州市设计院集团有限公司 Trapezoidal staggered foundation pit supporting mechanism and foundation pit supporting method
CN113605398A (en) * 2021-07-14 2021-11-05 广州市设计院集团有限公司 Foundation pit supporting mechanism
CN113653069A (en) * 2021-09-09 2021-11-16 浙江省三建建设集团有限公司 Pre-tensioning method prestress supporting structure of deep foundation pit and construction method thereof

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CN113605397A (en) * 2021-07-14 2021-11-05 广州市设计院集团有限公司 Trapezoidal staggered foundation pit supporting mechanism and foundation pit supporting method
CN113605398A (en) * 2021-07-14 2021-11-05 广州市设计院集团有限公司 Foundation pit supporting mechanism
CN113653069A (en) * 2021-09-09 2021-11-16 浙江省三建建设集团有限公司 Pre-tensioning method prestress supporting structure of deep foundation pit and construction method thereof

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