CN102943493B - Method for measuring internal force and deformation of precast pile - Google Patents
Method for measuring internal force and deformation of precast pile Download PDFInfo
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- CN102943493B CN102943493B CN201210514738.0A CN201210514738A CN102943493B CN 102943493 B CN102943493 B CN 102943493B CN 201210514738 A CN201210514738 A CN 201210514738A CN 102943493 B CN102943493 B CN 102943493B
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Abstract
The invention provides a method for measuring the internal force and the deformation of a precast pile. After a piling procedure is accomplished, a sensor and vertical pile foundation static load experiment equipment which is connected with the sensor are installed; before the next stage of load is exerted, the numerical reading of the sensor under one stage of load is recorded, namely, the relative deformation at an observation point (at which a force transmission rope is connected) and a reference part; the relative deformation is divided by the pile length of the section so as to obtain the relative strain of the observation section relative to a reference plane; the strain difference between two sections is obtained through the strains of two adjacent observation sections relative to the reference plane; and the axial force of the pile body at each anchoring head section is calculated according to the elastic modulus calibration result of the pile body concrete. According to the method for measuring the internal force and the deformation of the precast pile provided by the invention, the sensor is installed after the piling procedure is accomplished, so that the sensor is prevented from being damaged in the piling process, and moreover the measurement precision is high, and the cost can be controlled effectively.
Description
Technical field
The present invention relates to a kind of method of civil engineering pile foundation technical field of quality detection, be specifically related to a kind of method measuring preformed pile internal force and distortion.
Background technology
The base form that pile foundation adopts in a large number as engineering construction at present, little except having sedimentation, bearing capacity advantages of higher, it also relates to the important component part of structural safety, and the detection therefore for pile foundation is vital.
Main method at present for Internal forces test has reinforcing rib meter method and slide attack method.(1) reinforcing rib meter method: reinforcing rib meter is embedded on the main muscle of pile body according to substructure, detects a certain cross section of pile body and the ess-strain at the bottom of post.This method of testing principle is simple, testing element is easy to install, but can only the strain of measuring point, and the distortion between 2 can only lean on deduction, and because reinforcing rib meter is the average internal force extrapolating stake according to the strain of any on reinforcing bar, no small error can be there is like this.Because the sensors such as reinforcing rib meter need to be embedded in pile body, easily in the making and piling process of stake, cause damage, and affect test performance and the calibration coefficient of sensor, thus can motility rate be lowered into and affect test result.In addition, due to sensor pre-buried after can not recycle, belong to medical disposable material, the cost of the test of increase.(2) slide attack method: relative to reinforcing rib meter method, slide attack method can measure the strain on whole pile body axis under all each point axis directions load at different levels continuously, and can effectively revise drift zero.Although it is many that it has measuring point, continuity is good, precision advantages of higher, and the shortcoming that its cost is high is also a factor needing to consider.
Patent 200910056699.2 provides a kind of method, and at pile body by longitudinal service sleeve or directly at pile body longitudinal drilling, in sleeve pipe or boring, install and measure system, this measuring system is made up of anchor head, multiple position extensometer, extension bar and force pipe.According to the vertical deformation between stake top vertical displacement observed result and all adjacent two anchor head positions, calculate that the side resistance along depth of each soil layer in stake side, stake end bearing power and anchor head bury the vertical displacement of section underground, thus realize Internal forces and section vertical displacement measurement.
All there is at least one shortcoming in the above traditional method.Such as, the former precision is not high enough, and first installs due to sensor, easily produces damage problem; Although the latter's precision can reach requirement, high cost, economical not.
Summary of the invention
The object of the invention is to solve in prior art the problem of low precision or high cost when measuring preformed pile internal force and distortion.
To achieve these goals, the present invention proposes a kind of method measuring preformed pile internal force and distortion, it is characterized in that, comprises the following steps: determine observation point anchorage head quantity and the position burying section underground; Service sleeve on the pile body of described preformed pile is longitudinal; The benchmark anchorage head having hole is installed on the stake top of described preformed pile; In the described position burying section underground, described observation point anchorage head is installed, and described observation point anchorage head and described sleeve pipe are fixedly linked, if run into the situation of pile extension, then a jury anchor solid point is set in stake the last period, for being secured across the power transmission rope of pile extension section, described jury anchor solid point is arranged the hole passed through for described power transmission rope; Carry out piling operation, if desired pile extension, then proceed pile extension operation; One sensor is provided, by the hole on described benchmark anchorage head, is installed on described power transmission rope, and described sensor is demarcated; The pile foundation vertical static loading experiment equipment that is connected with described sensor is installed, before applying next stage load, records the sensor reading under certain grade of load, namely this power transmission rope connect the relative deformation of observation point place and benchmark place; This relative deformation is long divided by this section of stake, obtain the relative strain of measuring frequency section relative to datum, with the strain of adjacent two measuring frequency sections relative to datum, obtain the strain value between these two sections, according to pile concrete modulus of elasticity calibration result, calculate the pile shaft force of each anchorage head section part.
Optionally, comprise the following steps: the first step, according to the geotechnical investigation report in place, test pile place, construction note, regional experience and designing requirement determine suitable observation point anchorage head quantity and its bury cross section place underground; Second step, casing axis should be parallel to pile body longitudinal axis, and sleeve pipe should mate with the anchorage head selected; Bury sleeve pipe underground to be arranged symmetrically with along cross-section center axis direction, the benchmark anchorage head installed at stake top place, in the middle of need perforate, facilitate and last sensor to be loaded, at determined section part, observation point anchorage head is installed, anchorage head and sleeve pipe are firmly fixed, if meet the situation having pile extension, then need to arrange jury anchor solid point in stake the last period, the convenient power transmission rope fixedly needed through pile extension section, jury anchor solid point needs perforate so that allow power transmission rope by; 3rd step, starts piling, stake is squeezed into, if need pile extension, also carry out pile extension as requested according to normal construction process; 4th step, after stake is squeezed into, by the hole of stake top benchmark anchorage head, installs on power transmission rope by sensor, sensor requirements can load in sleeve pipe in the free-hand perforate by reference point anchorage head, and is stuck on power transmission rope; 5th step, installs conventional pile foundation vertical static loading experiment equipment, records load according to a conventional method after on-test; 6th step, stablize at certain grade of load action bottom offset, before applying next stage load, record the sensor reading under certain grade of load, namely this power transmission rope connect the relative deformation of observation point place and benchmark place, this relative deformation is long divided by this section of stake, obtain the relative strain of measuring frequency section relative to datum, with the strain of adjacent two measuring frequency sections relative to datum, obtain the strain value between these two sections, according to pile concrete modulus of elasticity calibration result, calculate the pile shaft force of each anchorage head section part.
The Advantageous Effects that the present invention measures the method for preformed pile internal force and distortion is: the method that the present invention measures preformed pile internal force and distortion takes sensor installation after completing piling operation, avoid sensor impaired in piling process, and certainty of measurement is high, can effectively control cost.
Accompanying drawing explanation
Fig. 1 is the apparatus structure schematic diagram that the present invention measures the method for preformed pile internal force and distortion.
Detailed description of the invention
Below, 1 the present invention is described in further detail by reference to the accompanying drawings.Label in Fig. 1: 1-observation point anchorage head; 2-sleeve pipe; 3-reference point anchorage head; 4-sensor; 5-power transmission rope; The temporary fixed point of 6-power transmission rope; 7-pile extension head; 8-data acquisition instrument.
Please refer to Fig. 1, Fig. 1 is the apparatus structure schematic diagram that the present invention measures the method for preformed pile internal force and distortion, and the concrete steps of the inventive method are:
(1) according to the geotechnical investigation report in place, test pile place, construction note, regional experience and designing requirement determine suitable observation point anchorage head quantity and its bury cross section place underground.Observation point anchorage head 1 generally can be embedded in the interface of two kinds of heterogeneity soil layers.
(2) sleeve pipe 2 is buried underground when stake processed.Sleeve pipe material will not limit, but requires that casing axis should be parallel to pile body longitudinal axis, and sleeve pipe 2 should mate with the observation point anchorage head 1 selected and reference point anchorage head 3; Bury sleeve pipe underground to be arranged symmetrically with along cross-section center axis direction.At stake top place reference for installation anchorage head 3, in the middle of benchmark anchorage head 3, need perforate, facilitate and last sensor 4 to be loaded.Install observation point anchorage head 1 at determined section part, by observation point anchorage head 1, reference point anchorage head 3 and sleeve pipe 2 are firmly fixed.With power transmission rope 5, each observation point anchorage head 1 is connected with benchmark anchorage head 3 respectively, if meet the situation having pile extension, then needs to arrange jury anchor solid point 6 in stake the last period, the convenient power transmission rope 5 fixedly needed through pile extension section.Jury anchor solid point 6 needs perforate so that allow power transmission rope by
(3) start piling, according to normal construction process, stake is squeezed into, if need pile extension, also carry out pile extension as requested.
(4), after stake is squeezed into, by the hole of stake top benchmark anchorage head 3, sensor 4 is put into stake, and be installed on power transmission rope 5.Transmit wire by data to be connected with the data acquisition instrument 8 of outside.Install the demarcation of laggard line sensor, namely standard volume inputs to sensor 4 undetermined, obtain the output quantity of sensor 4 simultaneously, obtained sensor input and output amount is compared and treated, thus obtain the calibration curve of a series of both signs corresponding relation, carry out the measured result obtaining sensor performance index.
(5) conventional pile foundation vertical static loading experiment equipment is installed, after on-test, records load according to a conventional method.
(6) stablize at certain grade of load action bottom offset, before applying next stage load, record the reading of the data acquisition instrument 8 under certain grade of load, be i.e. the relative deformation δ of the observation point place that connects of this power transmission rope and benchmark place.By this relative deformation δ divided by this section of long L of stake, then can obtain the relative strain ε of measuring frequency section for datum.ε=δ/L。With the strain of adjacent two measuring frequency sections relative to datum, then can obtain the strain value between these two sections.dε
i=ε
i+1-ε
i。ε
ibe the strain value of i-th observation point anchorage head place relative to datum.According to pile concrete modulus of elasticity calibration result E=f (ε), pile body cross sectional area A, then can calculate the pile shaft force N of each anchorage head section part
i=EA d ε
i.
Although the present invention with preferred embodiment disclose as above, so itself and be not used to limit the present invention.Have in technical field of the present invention and usually know the knowledgeable, without departing from the spirit and scope of the present invention, when being used for a variety of modifications and variations.Therefore, protection scope of the present invention is when being as the criterion depending on those as defined in claim.
Claims (2)
1. measure a method for preformed pile internal force and distortion, it is characterized in that, comprise the following steps:
Determine observation point anchorage head quantity and the position burying section underground;
Service sleeve on the pile body of described preformed pile is longitudinal;
The benchmark anchorage head having hole is installed on the stake top of described preformed pile;
In the described position burying section underground, described observation point anchorage head is installed, and described observation point anchorage head and described sleeve pipe are fixedly linked, be connected by power transmission rope between described observation point anchorage head with described benchmark anchorage head, if run into the situation of pile extension, described power transmission rope is through pile extension section, then a jury anchor solid point being set in stake the last period, for being secured across the described power transmission rope of described pile extension section, described jury anchor solid point being arranged the hole passed through for described power transmission rope;
Carry out piling operation, if desired pile extension, then proceed pile extension operation;
One sensor is provided, by the hole on described benchmark anchorage head, is installed on described power transmission rope, and described sensor is demarcated;
The pile foundation vertical static loading experiment equipment that is connected with described sensor is installed, before applying next stage load, records the sensor reading under certain grade of load, namely this power transmission rope connect the relative deformation of observation point place and benchmark place;
This relative deformation is long divided by this section of stake, obtain the relative strain of measuring frequency section relative to datum, with the strain of adjacent two measuring frequency sections relative to datum, obtain the strain value between these two sections, according to pile concrete modulus of elasticity calibration result, calculate the pile shaft force of each anchorage head section part.
2. the method for measurement preformed pile internal force according to claim 1 and distortion, is characterized in that, comprise the following steps:
The first step, according to the geotechnical investigation report in place, test pile place, construction note, regional experience and designing requirement determine suitable observation point anchorage head quantity and its bury cross section place underground;
Second step, casing axis should be parallel to pile body longitudinal axis, and sleeve pipe should mate with the anchorage head selected, bury sleeve pipe underground to be arranged symmetrically with along cross-section center axis direction, the benchmark anchorage head installed at stake top place, in the middle of need perforate, facilitate and last sensor to be loaded, at determined section part, observation point anchorage head is installed, anchorage head and sleeve pipe are firmly fixed, be connected by power transmission rope between described observation point anchorage head with described benchmark anchorage head, if meet the situation having pile extension, described power transmission rope is through pile extension section, then need to arrange jury anchor solid point in stake the last period, the convenient fixing described power transmission rope needed through described pile extension section, jury anchor solid point needs perforate, so that allow power transmission rope by,
3rd step, starts piling, stake is squeezed into, if need pile extension, also carry out pile extension as requested according to normal construction process;
4th step, after stake is squeezed into, by the hole of stake top benchmark anchorage head, installs on power transmission rope by sensor, sensor requirements can load in sleeve pipe in the free-hand perforate by reference point anchorage head, and is stuck on power transmission rope;
5th step, installs conventional pile foundation vertical static loading experiment equipment, records load according to a conventional method after on-test;
6th step, stablize at certain grade of load action bottom offset, before applying next stage load, record the sensor reading under certain grade of load, namely this power transmission rope connect the relative deformation of observation point place and benchmark place, this relative deformation is long divided by this section of stake, obtain the relative strain of measuring frequency section relative to datum, with the strain of adjacent two measuring frequency sections relative to datum, obtain the strain value between these two sections, according to pile concrete modulus of elasticity calibration result, calculate the pile shaft force of each anchorage head section part.
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| JP2016500807A (en) * | 2013-08-16 | 2016-01-14 | コーニンクレッカ フィリップス エヌ ヴェＫｏｎｉｎｋｌｉｊｋｅ Ｐｈｉｌｉｐｓ Ｎ．Ｖ． | System and method for detecting physical deformation of pillars |
| CN103967057B (en) * | 2014-04-30 | 2016-08-17 | 河海大学 | Soil displacement field visual test device and using method in a kind of pile driving process |
| CN104075664A (en) * | 2014-07-02 | 2014-10-01 | 中国矿业大学 | Shaft deformation rapid scanning and obtaining device |
| CN104631518B (en) * | 2015-01-04 | 2016-11-30 | 东南大学 | A kind of rearmounted sensor openings steel-pipe pile Internal Force Monitoring equipment |
| CN105133671B (en) * | 2015-08-26 | 2017-03-22 | 上海交通大学 | Device for connecting indoor vertical static load model pile with pressure sensor |
| CN105696633B (en) * | 2016-03-31 | 2018-08-07 | 中国电建集团华东勘测设计研究院有限公司 | A kind of friction pile supporting effect monitoring system and monitoring method |
| CN105821912B (en) * | 2016-04-01 | 2017-12-22 | 上海筑邦测控科技有限公司 | Detect method, intelligent foundation ditch support meanss and the intelligent foundation pit support system of foundation ditch axial force of the supports |
| CN111576504B (en) * | 2020-05-29 | 2022-05-03 | 武汉至科检测技术有限公司 | PHC pile body internal force testing method based on optical fiber strain and optical fiber layout method |
| CN111576507A (en) * | 2020-05-29 | 2020-08-25 | 海安东大岩土桩基工程检测有限公司 | Method for measuring displacement and internal force of pile foundation |
| CN115075309B (en) * | 2022-07-27 | 2023-08-18 | 河海大学 | Pile shaft axial force and side friction resistance testing system and method |
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