CN116752587A - In-situ static force detection method for bearing capacity of pile foundation of existing building - Google Patents

In-situ static force detection method for bearing capacity of pile foundation of existing building Download PDF

Info

Publication number
CN116752587A
CN116752587A CN202310931104.3A CN202310931104A CN116752587A CN 116752587 A CN116752587 A CN 116752587A CN 202310931104 A CN202310931104 A CN 202310931104A CN 116752587 A CN116752587 A CN 116752587A
Authority
CN
China
Prior art keywords
bearing platform
pile foundation
upper structure
bearing
bearing capacity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202310931104.3A
Other languages
Chinese (zh)
Inventor
徐玉洁
徐超
王文通
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Foshan Anguzhi Housing Inspection And Appraisal Co ltd
Original Assignee
Foshan Anguzhi Housing Inspection And Appraisal Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Foshan Anguzhi Housing Inspection And Appraisal Co ltd filed Critical Foshan Anguzhi Housing Inspection And Appraisal Co ltd
Priority to CN202310931104.3A priority Critical patent/CN116752587A/en
Publication of CN116752587A publication Critical patent/CN116752587A/en
Pending legal-status Critical Current

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D33/00—Testing foundations or foundation structures
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D27/00—Foundations as substructures
    • E02D27/10—Deep foundations
    • E02D27/12—Pile foundations
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D27/00—Foundations as substructures
    • E02D27/10—Deep foundations
    • E02D27/12—Pile foundations
    • E02D27/14—Pile framings, i.e. piles assembled to form the substructure
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/10—Geometric CAD
    • G06F30/13—Architectural design, e.g. computer-aided architectural design [CAAD] related to design of buildings, bridges, landscapes, production plants or roads
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Geometry (AREA)
  • Theoretical Computer Science (AREA)
  • Civil Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • Paleontology (AREA)
  • Computer Hardware Design (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Evolutionary Computation (AREA)
  • Architecture (AREA)
  • Computational Mathematics (AREA)
  • Mathematical Analysis (AREA)
  • Mathematical Optimization (AREA)
  • Pure & Applied Mathematics (AREA)
  • Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)

Abstract

According to the in-situ static force detection method for the bearing capacity of the pile foundation of the existing building, the relation between the settlement of the bearing platform and the external load N1 is measured through a static force test, and then the counter force N2 of the upper structure of the bearing platform with different settlement amounts is obtained through finite element analysis. And finally, calculating the pile foundation bearing capacity according to the static test result, the upper structure counter force N2 and the dead weight N3, avoiding damage to the upper structure in the detection process, and simultaneously considering the influence of the counter force generated by the settlement of the bearing platform on the pile foundation bearing capacity detection result.

Description

In-situ static force detection method for bearing capacity of pile foundation of existing building
Technical Field
The invention relates to the technical field of building measurement, in particular to an in-situ static force detection method for the bearing capacity of a pile foundation of an existing building.
Background
Whether the bearing capacity of the pile foundation after the foundation construction is detected can meet the design requirement is a precondition for guaranteeing the safe use of the whole structure. The existing pile foundation detection and standard is a single pile foundation for a newly built building, and the pile foundation bearing capacity detection can not be carried out under the condition of not dismantling and damaging an upper structure in the reconstruction and extension engineering of the existing building.
Disclosure of Invention
In order to overcome the defect that the pile foundation bearing capacity detection cannot be carried out under the condition that an upper structure is not dismantled and damaged in the prior art, the invention provides an in-situ static force detection method for the pile foundation bearing capacity of an existing building, and the pile foundation bearing capacity can be safely and rapidly detected under the condition that the existing structure is not damaged.
The invention provides an in-situ static force detection method for the bearing capacity of a pile foundation of an existing building, which comprises the following steps:
s1, excavating soil around a bearing platform;
s2, arranging a bearing platform settlement observation point on the bearing platform; selecting a deformation monitoring target from the pillars around the bearing platform, and arranging deformation monitoring points on the deformation monitoring target; arranging crack observation points on the upper structure; the upper structure comprises a part of the bearing platform exposed above the ground and a building structure borne by the bearing platform;
s3, carrying out a bearing platform stacking test, and recording external load data N1, wherein the external load data N1 is the maximum load which can be loaded by the bearing platform in the bearing platform stacking test.
Preferably, in the step S2, a total station is arranged at the deformation monitoring point, and the deformation quantity of the deformation monitoring point is measured through the triangular elevation of the point method of the total station; and in the measuring process, the column farthest from the loading area in the same building is used as a datum point.
Preferably, the external load data N1 is a smaller value of two:
C. the largest external load applied by the bearing platform stacking test, namely the external load applied by the bearing platform stacking test when the settlement amount of the bearing platform reaches a set settlement value or the deformation amount of the deformation monitoring point reaches a set deformation value;
D. and when the maximum crack width at the crack observation point reaches a set limit value, carrying out external load applied by a pile test by the bearing platform.
Preferably, a crack observation point is provided at a beam end adjacent to the deck in the upper structure.
Preferably, the following steps are further included after S3:
s4, establishing a finite element analysis model of the upper structure of the bearing platform;
s5, calculating the upper structure reaction N2 caused by the subsidence of the bearing platform through a finite element model;
s6, calculating the dead weight load N3 of the upper structure, namely the dead weight of the upper structure;
s7, calculating pile foundation bearing capacity (N) of bearing platform 1 -N 2 +N 3 ) And/(kn), wherein k is a safety coefficient, and n is the number of piles under a single bearing platform.
Preferably, k takes a value of 2.0.
The invention has the advantages that:
(1) According to the in-situ static force detection method for the bearing capacity of the pile foundation of the existing building, the relation between the settlement of the bearing platform and the external load N1 is measured through a static force test, and then the counter force N2 of the upper structure of the bearing platform with different settlement amounts is obtained through finite element analysis. And finally, calculating the pile foundation bearing capacity according to the static test result, the upper structure counter force N2 and the dead weight N3, avoiding damage to the upper structure in the detection process, and simultaneously considering the influence of the counter force generated by the settlement of the bearing platform on the pile foundation bearing capacity detection result.
(2) When the pile foundation bearing capacity detection is carried out in the existing building under reconstruction and extension, the pile foundation bearing capacity detection result is higher due to the fact that the upper structure reaction force is ignored, and when the pile foundation design calculation is carried out by directly using the detection result, the result is unsafe.
Drawings
FIG. 1 is a flow chart of an implementation of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
As shown in fig. 1, the in-situ static force detection method for the bearing capacity of the pile foundation of the existing building provided by the embodiment comprises the following steps:
s1, excavating soil around a bearing platform so that the bearing platform is exposed and the space requirement for carrying out a bearing platform stacking test is met;
according to engineering experience in the concrete implementation process of the step, a bearing platform needing to be excavated is determined by combining design parameters and geological conditions, structural positioning is well performed, and damage to pile foundations in the excavation process is avoided, and detection results are affected.
S2, arranging a bearing platform settlement observation point on the bearing platform, wherein the bearing platform settlement observation point is used for observing the settlement of the bearing platform after load loading; selecting a deformation monitoring target from the pillars around the bearing platform according to the detection requirement, and arranging deformation monitoring points on the deformation monitoring target, wherein the deformation monitoring points are used for observing the deformation of the deformation monitoring target; arranging crack observation points on the upper structure for observing crack development conditions of the upper structure; the superstructure comprises a portion of the platform exposed above the ground and a building structure carried by the platform.
According to engineering experience, deformation monitoring points are arranged at positions which are not easily affected by construction sites, and corresponding protection measures are taken. In the concrete implementation, the deformation quantity of the deformation monitoring point is measured through the point method triangle elevation of the total station, and the column farthest from the loading area in the same building is used as a datum point in the calculation of the deformation quantity.
S3, carrying out a bearing platform stacking test, and recording external load data N1, wherein the external load data N1 is the maximum load which can be loaded by the bearing platform in the bearing platform stacking test.
Specifically, in the step S3, the required weight and quantity of the balancing weights are determined according to the indoor height and the bearing capacity of the bearing platform, that is, the bearing platform load to be loaded is determined according to the indoor height and the existing upper structure weight; and in the bearing platform stacking test process, a wide-range dial indicator is adopted to collect the bearing platform settlement amount at the bearing platform settlement observation point in real time.
When the stacking load reaches a limit load or the bearing platform subsides to cause the development of the upper structure crack to be unsuitable for continuous loading, namely the crack development at the crack observation point reaches a limit value, ending the test; and recording the load loaded by the bearing platform at the moment, namely the external load data N1.
The limit load is the maximum external load which can be applied by the bearing platform stacking test, namely the external load which is applied by the bearing platform stacking test when the settlement amount of the bearing platform reaches a set settlement value or the deformation amount of the deformation monitoring point reaches a set deformation value;
the crack observation points are arranged, so that the crack development condition of the upper structure in the load loading process can be observed in real time, namely, the observation of the damage state of the upper structure is realized, and the damage of the upper structure caused by excessively increasing the external load in the test process is avoided. Specifically, a crack observation point can be arranged at the beam end adjacent to the bearing platform in the upper structure, the loading rate is controlled according to the observed crack width, when the maximum crack width is close to a set limit value, the loading rate is slowed down, and when the maximum crack width reaches the limit value, the test is stopped, namely the loading load is stopped.
S4, establishing a finite element analysis model of the upper structure of the bearing platform;
specifically, proper finite element software such as ABAQUS, PKPM, midas and the like can be adopted according to actual conditions, the modeling is required to be established according to actual component sizes, concrete strength and reinforcement conditions, and when the structure is complex and needs to be simplified, relevant theoretical basis is required. The material parameters required to be input by different software are different, but the requirements of relevant specifications are met. The finite element analysis model may be constructed by any conventional method, and will not be described herein.
S5, calculating the upper structure reaction N2 caused by the subsidence of the bearing platform through a finite element model;
specifically, according to the bearing platform settlement amount detected by the bearing platform settlement observation point in the test process, a finite element analysis model is adjusted according to the external load increased in the test process, and the bearing platform settlement amount is increased on the finite element analysis model, so that the stress distribution of the upper structure and the counter force of the upper structure are obtained.
The superstructure reaction force means a reaction force generated by the superstructure due to the bearing platform settlement amount.
S6, calculating the dead weight load N3 of the upper structure, namely the dead weight of the upper structure;
the self-weight load of the upper structure has obvious influence on the detection result, and neglecting the load can lead to small bearing capacity of the obtained pile foundation, so that the actual load condition of the upper structure is combined, and the self-weight of the upper structure is calculated to be used as the self-weight load N3 of the upper structure.
It is noted that after the finite element analysis model is established in S5, N2 and N3 are obtained by calculation of the finite element analysis model, which is the prior art and will not be described herein.
In addition, N3 can also be calculated in the case of perfect structural design data of the upper part.
S7, calculating pile foundation bearing capacity (N) 1 -N 2 +N 3 ) /(kn); k is a safety coefficient, and the value of k is 2.0; n is the number of piles under a single bearing platform.
It will be understood by those skilled in the art that the present invention is not limited to the details of the foregoing exemplary embodiments, but includes other specific forms of the same or similar structures that may be embodied without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined as appropriate to form other embodiments that will be apparent to those skilled in the art.
The technology, shape, and construction parts of the present invention, which are not described in detail, are known in the art.

Claims (6)

1. The in-situ static force detection method for the bearing capacity of the pile foundation of the existing building is characterized by comprising the following steps of:
s1, excavating soil around a bearing platform;
s2, arranging a bearing platform settlement observation point on the bearing platform; selecting a deformation monitoring target from the pillars around the bearing platform, and arranging deformation monitoring points on the deformation monitoring target; arranging crack observation points on the upper structure; the upper structure comprises a part of the bearing platform exposed above the ground and a building structure borne by the bearing platform;
s3, carrying out a bearing platform stacking test, and recording external load data N1, wherein the external load data N1 is the maximum load which can be loaded by the bearing platform in the bearing platform stacking test.
2. The in-situ static force detection method for the bearing capacity of the pile foundation of the existing building according to claim 1, wherein a total station is arranged at a deformation monitoring point in the S2, and the deformation of the deformation monitoring point is measured through a point method triangle elevation of the total station; and in the measuring process, the column farthest from the loading area in the same building is used as a datum point.
3. The method for in-situ static detection of bearing capacity of pile foundation of existing building according to claim 1, wherein the external load data N1 is a smaller value of the following two:
A. the largest external load applied by the bearing platform stacking test, namely the external load applied by the bearing platform stacking test when the settlement amount of the bearing platform reaches a set settlement value or the deformation amount of the deformation monitoring point reaches a set deformation value;
B. and when the maximum crack width at the crack observation point reaches a set limit value, carrying out external load applied by a pile test by the bearing platform.
4. The method for in-situ static force detection of pile foundation bearing capacity of existing building according to claim 1, wherein crack observation points are arranged at beam ends adjacent to bearing platforms in the upper structure.
5. The method for in-situ static force detection of bearing capacity of pile foundation of existing building according to claim 1, further comprising the following steps after S3:
s4, establishing a finite element analysis model of the upper structure of the bearing platform;
s5, calculating the upper structure reaction N2 caused by the subsidence of the bearing platform through a finite element model;
s6, calculating the dead weight load N3 of the upper structure, namely the dead weight of the upper structure;
s7, calculating pile foundation bearing capacity (N) of bearing platform 1 -N 2 +N 3 ) And/(kn), wherein k is a safety coefficient, and n is the number of piles under a single bearing platform.
6. The method for in-situ static detection of bearing capacity of pile foundation of existing building according to claim 1, wherein k has a value of 2.0.
CN202310931104.3A 2023-07-27 2023-07-27 In-situ static force detection method for bearing capacity of pile foundation of existing building Pending CN116752587A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310931104.3A CN116752587A (en) 2023-07-27 2023-07-27 In-situ static force detection method for bearing capacity of pile foundation of existing building

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310931104.3A CN116752587A (en) 2023-07-27 2023-07-27 In-situ static force detection method for bearing capacity of pile foundation of existing building

Publications (1)

Publication Number Publication Date
CN116752587A true CN116752587A (en) 2023-09-15

Family

ID=87949854

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310931104.3A Pending CN116752587A (en) 2023-07-27 2023-07-27 In-situ static force detection method for bearing capacity of pile foundation of existing building

Country Status (1)

Country Link
CN (1) CN116752587A (en)

Similar Documents

Publication Publication Date Title
CN107975075B (en) Construction process for existing load-bearing engineering foundation pile detection structure measures
CN107894311A (en) The model test method of earth and rockfill dam eaerthquake damage
CN211816467U (en) Bored concrete pile anchor piles combination method static load pile-pressing test device
Altunisik et al. Non-destructive modal parameter identification of historical timber bridges using ambient vibration tests after restoration
CN106013270A (en) Combined load loading device for pile foundation in field testing
Chang et al. Seismic performance of an existing bridge with scoured caisson foundation
Miśkiewicz et al. Monitoring system of the road embankment
CN115753338A (en) Composite bearing capacity test device and method based on power transmission tower anchor cable bearing platform
CN211773959U (en) Model pile testing device and testing system thereof
CN210917508U (en) Large-tonnage foundation pile static load high-precision detection device
Qian et al. Comparative field tests on straight-sided and belled piers on sloping ground under combined uplift and lateral loads
CN105780825B (en) A kind of pile foundation construction environmental Kuznets Curves and evaluation method based on autobalanced detection experiment
CN116752587A (en) In-situ static force detection method for bearing capacity of pile foundation of existing building
CN111402701A (en) Equal-load replacement light roadbed bearing detection simulation device and implementation method
Zheng et al. Numerical study of deformation behavior for a geosynthetic-reinforced soil bridge abutment under static loading
CN115081311A (en) Foundation pit support monitoring and early warning method and foundation pit support monitoring and early warning system
Pathak Analysis of static lateral load test of battered pile group at I-10 twin span bridge
CN104181044B (en) A kind of horizontal load-bearing body soil pressure measurement test method
CN114541489A (en) Power transmission line rod plate type foundation settlement test and repair method
Endicott Case histories of failure of deep excavation. Examination of where things went wrong: Nicoll Highway Collapse, Singapore
CN106017792A (en) Simple device for simultaneous calibration of three earth pressure boxes
Shid Moosavi et al. The Performance of Integral and Semi-integral Pre-tensioned Concrete Bridges Under Seismic Loads in Comparison with Conventional Bridges
JP4176767B2 (en) Basic bottom structure calculation method, calculation program thereof, and recording medium for the program
JP4040891B2 (en) Method for adjusting level of building and settlement measuring device
RU2494194C2 (en) Method to construct buildings, structures on unevenly compressible soils

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination