CN111622276A - Method for detecting vertical pressure-pull resistance of single pile foundation - Google Patents
Method for detecting vertical pressure-pull resistance of single pile foundation Download PDFInfo
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Abstract
The invention relates to a method for detecting the vertical pressure-pulling resistance of a single pile foundation, and relates to the field of constructional engineering detection. The method comprises the steps of carrying out leveling treatment on the pile top part of a pile foundation to be detected; applying vertical pressure load to the pile foundation to be detected step by step through a pile foundation compression resistance detection device; measuring and reading the settlement of the pile foundation to be measured after each stage of pressure load is completed; unloading the vertical pressure load step by step, and measuring and reading the settlement of the pile foundation to be detected at each step; leveling the pile top part of the pile foundation to be detected again; applying vertical tension load to the pile foundation to be tested step by step through a pile foundation uplift detection device; after each stage of tensile load is finished, the uplift deformation of the pile foundation to be tested is measured and read; and (4) unloading the vertical pressure load step by step, and measuring and reading the uplift deformation of the pile foundation to be tested at each step. The invention not only ensures that the compression and pulling resistance detection result of the invention is more accurate, but also can not cause destructive influence on the pile top part of the pile foundation to be detected.
Description
Technical Field
The invention relates to the field of constructional engineering detection, in particular to a method for detecting vertical pressure-pull resistance of a single pile foundation.
Background
In construction engineering, foundation engineering has the characteristics of importance and concealment, and pile foundation quality plays an important role in foundation engineering safety. The vertical bearing capacity and the anti-pulling performance of the pile foundation are important indexes for measuring the quality of the pile foundation, and the conventional pile foundation detection method can only realize the function of single anti-pressing detection or anti-pulling detection basically.
In order to solve the above technical problems, a system and a method for testing pile foundation resistance to plucking and compression (publication number: CN 105040749A) are searched, and the method comprises the following steps: checking and confirming that the pulling and loading jack is in an unloading state; removing the pull-load nuts at the lower ends of all the pull-load pull rods; starting a ballast jack, applying pressure to the pile foundation, and carrying out compression resistance detection; unloading the ballast jack; completely assembling and screwing down the pull-load nuts at the lower end of the pull-load pull rod; and opening the pulling and loading jack, and applying pulling force to the pile foundation through the pulling and loading pull rod to perform uplift detection.
The above prior art solutions have the following drawbacks:
1. the prior art only simply records the method for realizing the tensile or anti-pulling function of the pile foundation anti-pulling and anti-pressing test system, and when detecting the actual tensile and anti-pulling, people should detect the anti-pulling and anti-pressing of the pile foundation to be detected through the pile foundation anti-pulling and anti-pressing test system and pay attention to the items during the detection, and the prior art is not recorded;
2. because the jack specification that resistance to compression resistance to plucking experimental adoption is 5000 kN's jack basically, and above-mentioned current resistance to plucking compression test system middling pressure carries the jack and draws and carry the jack and all be connected with the crossbeam middle part, and the equipartition is in the pile foundation top that awaits measuring, consequently, when adopting above-mentioned current resistance to plucking compression test system to carry out resistance to plucking, the settlement volume and the deformation that rises of pile foundation that awaits measuring all receive the influence of jack great, the resistance to plucking performance of pile foundation self that can not more accurate reaction awaits measuring.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide the method for detecting the vertical uplift resistance of the single pile foundation, which can realize the anti-compression and uplift detection of the pile foundation to be detected, and has the advantages of less influence of the self weight of a jack on the pile foundation to be detected and more accurate detection result.
The above object of the present invention is achieved by the following technical solutions:
a method for detecting the vertical anti-pressure-and-pull performance of a single pile foundation comprises the steps of detecting the vertical anti-pressure of the single pile foundation by a pile foundation to be detected consisting of a pile top and a pile body, detecting the vertical anti-pressure of the single pile foundation, detecting the vertical anti-pull performance of the single pile foundation after the vertical anti-pressure detection is finished, wherein,
the vertical compression resistance detection of the single pile foundation comprises the following steps,
s1, when the pile foundation to be tested reaches the rest period required by the construction specification of the building engineering, and after the pile foundation is subjected to low strain detection, carrying out leveling treatment on the pile top of the pile foundation to be tested, so that the concrete quality and the section size of the pile top of the pile foundation to be tested are equal to the design conditions of the pile body in the construction drawing;
s2, arranging a pile foundation compression resistance detection device which is provided with a jack and used for applying vertical load to the pile foundation to be detected on the pile foundation to be detected, and applying vertical pressure load to the foundation pile to be detected through the jack;
s3, when pressure load is applied to the pile foundation to be tested, loading the pile foundation to be tested by adopting a slow-speed load-maintaining method, adding the next stage of load after each stage of load is relatively stable, and measuring and reading the settlement of the pile foundation to be tested, wherein the interval time for measuring and reading the settlement of the pile foundation to be tested is the time after each stage of loading is completed;
s4, after the pile foundation compression resistance detection reaches the maximum applied load value, the load in the step S3 is unloaded in a grading mode, when the load is unloaded, the unloading value of each grade is twice of the loading value, the load is measured and read once every 15min after the load is unloaded, the load is read once every 30min after the load is read twice, then the load of the first grade is unloaded, and the load is measured and read once every 3h after the load is completely unloaded;
the vertical uplift resistance detection of the single pile foundation comprises the following steps,
k1, in a rest period required by construction specifications of the building engineering, after the pile foundation to be detected is subjected to vertical compression resistance detection, leveling the pile top of the pile foundation to be detected again to ensure that the concrete quality and the section size of the pile top of the pile foundation to be detected are equal to the design conditions of the pile body in the construction drawing;
k2, arranging a pile foundation anti-pulling detection device which is provided with a jack and is used for applying vertical pulling force to the pile foundation to be detected on the pile foundation to be detected, and applying vertical pulling force load to the foundation pile through the jack;
k3, when a tensile load is applied to the pile foundation to be tested, loading by adopting a slow load maintaining method, adding the next level of load after each level of load is relatively stable, and measuring and reading the rising deformation of the pile foundation to be tested, wherein the interval time for measuring and reading the rising deformation of the pile foundation to be tested is the time after each level of loading is finished;
and K4, when the termination detection condition of the vertical uplift detection is met, terminating the detection, unloading and reading and recording the resilience variable of the pile foundation to be detected.
By adopting the technical scheme, the compression resistance detection and the pull-out resistance detection of the pile foundation to be detected can be realized simultaneously by leveling the pile top, loading step by step, unloading step by step, reading the reading of a pressure gauge or a tension gauge step by step and the like; meanwhile, the uplift detection is set to be carried out after the anti-compression detection is finished, so that when the anti-compression or anti-compression detection is carried out on the pile foundation to be detected, too many jacks do not need to be arranged on the detection device at one time, and the pressure or the tension of the jacks on the top of the pile foundation to be detected is smaller, so that the anti-compression and anti-compression detection result is more accurate, and the pile top part of the pile foundation to be detected cannot be destructively influenced.
In actual work, when the compression resistance of the pile foundation to be detected is detected, the compression resistance or the uplift resistance of the pile foundation to be detected can be detected by adopting the existing compression resistance detection device or uplift resistance detection device, or by adopting the compression resistance detection device or uplift resistance detection device provided by the invention.
In a preferred example, the present invention may be further configured that, in step S2, the load amount of the vertical pressure load is converted by the jack calibration curve, and is measured and read by the oil pressure gauge, and the load-oil pressure value correspondence table is established on site. By adopting the technical scheme, the calibration curve can help people to accurately control the pressure of the pile foundation to be tested, and the load-oil pressure value corresponding table can be convenient for personnel to carry out field operation.
The invention may further be configured in a preferred example, in step S2, the pile foundation compression resistance detection device includes a pile foundation to be detected, a pillow pile, a first steel beam, a first jack, an oil pressure gauge, and a counterweight made of precast concrete, the pillow piles are symmetrically arranged on two sides of the pile foundation to be detected, the first steel beam is erected between the tops of the two pillow piles, the first jack is located between the top of the pile foundation and the middle of the first steel beam, the counterweight is provided with a plurality of weights, the weights are all erected on the upper end of the first steel beam, and the oil pressure gauge is arranged on the pile foundation to be detected.
By adopting the technical scheme, the balancing weight is used for applying a reverse force to the first steel cross beam, the oil pressure gauge is used for measuring the pressure applied to the pile foundation to be detected by the first jack, and the pile foundation compression resistance detection device can be used for carrying out compression resistance detection on the pile foundation to be detected.
In a preferred example, the present invention may be further configured that, in step S3 and step K3, if the settling amount or the rising deformation amount of the pile foundation to be tested in 1 hour is not greater than 0.1mm twice in succession, it is determined that the settling amount of the pile foundation to be tested at the current stage has reached relatively stable, and the next stage of load may be applied to the pile foundation to be tested. Through adopting above-mentioned technical scheme, people can be accurate judge whether the pile foundation that awaits measuring is in steady state, and then help people to judge whether need apply next grade load.
The present invention in a preferred example may be further configured that, in the step S1 and the step K1, the step of performing the leveling process on the pile top of the pile foundation includes the steps of: a. chiseling off loose and damaged parts of the pile top on the pile foundation to be detected to expose the hard concrete surface of the pile foundation to be detected; b. leveling and cleaning the pile top surface of the pile foundation to be detected, and ensuring that no water is accumulated on the pile top surface of the pile foundation to be detected; c. cutting off exposed main ribs of the pile top, which hinder normal testing, on the pile foundation to be tested; d. when the pile top of the pile foundation to be tested is connected with a bearing platform or a cushion layer of the building engineering, the large section impedance change exists at the pile top, which is equivalent to influence on a test signal, so that the pile top of the pile foundation to be tested is disconnected with a concrete bearing platform; when the side surface of the pile top is connected with a cushion layer of the building engineering, the pile foundation to be tested and the cushion layer are disconnected unless the test signal is not influenced.
By adopting the technical scheme, the pile top (pile head) of the pile foundation to be tested can be processed to meet the requirements of compression resistance and compression resistance detection, the influence of the pile top on the compression resistance and the pull-out resistance detection can be reduced, and the quality of a test signal is directly improved.
In a preferred example, the invention may be further configured that, in step S3 and step K3, the load application amount of each stage is 1/8 of the design limit bearing capacity, the first stage addition amount is 1/4 of the characteristic value of the bearing capacity, after the load of each stage reaches relative stability, the next stage of load cannot be applied until the pile foundation compression resistance detection reaches the maximum application load value, and then the loading is terminated; after each stage of applied pressure load is finished, measuring and reading the settlement amount or the rising deformation amount of the pile top at 5min, 15min, 30min, 45min and 60min in sequence, and then measuring and reading the settlement amount or the rising deformation amount of the pile top once every 30 min.
By adopting the technical scheme, the stability of each stage of load is improved by strictly controlling the load quantity applied to each stage, and meanwhile, the time for measuring and reading the settlement quantity of the pile top is strictly controlled, so that people can be helped to more accurately observe the influence of the pressure or the tension on the pile foundation to be measured.
The invention in a preferred example may be further configured to terminate loading when a vertical pressure load is applied if one of the following three conditions occurs: a. under the action of a certain level of load, the settlement of the pile foundation to be detected is 5 times of that of the previous level of load, and the total settlement of the pile top exceeds 40 mm; b. under the action of a certain level of load capacity, the settlement of the pile foundation to be detected is 2 times greater than that of the pile foundation to be detected under the action of the previous level of load, and the pile foundation to be detected is not relatively stable for 24 hours; c. the design maximum applied load has been reached.
By adopting the technical scheme, the influence of the vertical pressure load on the pile foundation to be measured can be reduced, so that the measurement accuracy of the vertical pressure load is improved.
In a preferred example of the present invention, in step K2, the pile foundation uplift detection apparatus includes a pile foundation to be detected, two support tables, a second steel beam and a dial indicator, wherein the two support tables are symmetrically distributed on two sides of the pile foundation to be detected, the second steel beam is located above the pile foundation to be detected, the two support tables are respectively provided with a second jack, output ends of the two second jacks are respectively connected to two sides of the second steel beam, a mechanical fixture or a steel bar is connected between a middle portion of the second steel beam and the pile foundation to be detected, and the dial indicator has a plurality of dial indicators and is installed on two sides of a pile body of the pile foundation to be detected.
By adopting the technical scheme, the jack is used for applying tension to the first steel cross beam so as to apply tension to the pile foundation to be detected, the dial indicator is used for measuring the rising deformation applied to the pile foundation to be detected, and the pile foundation uplift detection device can be used for carrying out uplift detection on the pile foundation to be detected.
The present invention in a preferred example may be further configured that, in step S3, the maximum applied load value is twice the design load-bearing characteristic value; in step K5, the destructive test coupon does not read the unload rebound variable. By adopting the technical scheme, people can more accurately measure and read the settlement amount and the rising deformation amount of the pile foundation to be measured.
The present invention in a preferred example may be further configured to terminate loading when a vertical tensile load is applied if one of four conditions occurs: k5.1: under the action of a certain level of load, the upward pulling amount of the pile top is 5 times larger than that under the action of the previous level of upward pulling load; k5.2: controlling the pulling amount of the pile top according to the pulling amount of the pile top, and when the accumulated pulling amount of the pile top exceeds 100 mm; k5.3: controlling according to the tensile strength of the steel bar, wherein the pulling load on the pile top reaches 0.9 time of the standard value of the strength of the steel bar; k5.4: and for the pile foundation to be tested which is subjected to acceptance sampling detection, the maximum upper pulling load value of the design requirement is reached.
By adopting the technical scheme, the influence of the vertical pressure load on the pile foundation to be measured can be reduced, so that the measurement accuracy of the vertical pressure load is improved.
In summary, the invention includes at least one of the following beneficial technical effects:
1. according to the invention, the compression resistance detection and the uplift resistance detection of the pile foundation to be detected can be realized simultaneously by leveling the pile top, loading step by step, unloading step by step, reading the reading of a pressure gauge or a tension gauge step by step and the like.
2. Because the anti-pulling detection is set to be carried out after the anti-pulling detection is finished, when the anti-pulling or anti-pulling detection is carried out on the pile foundation to be detected, the detection device is not required to be provided with too many jacks at one time, so that the pressure or the tension of the jack on the top of the pile foundation to be detected is smaller, the anti-pulling and anti-pulling detection result of the invention is more accurate, and the pile top part of the pile foundation to be detected is not damaged.
3. The compression resistance detection device and the uplift resistance detection device provided by the invention have the advantages of simple structure, convenient addition and low construction cost, and meanwhile, when the compression resistance performance of the pile foundation to be detected is detected, the adopted device or equipment for detecting the compression resistance or the uplift resistance of the pile foundation to be detected can adopt the existing compression resistance detection device or uplift resistance detection device, and also can adopt the compression resistance detection device or the uplift resistance detection device provided by the invention.
Drawings
FIG. 1 is a schematic flow chart of the method for detecting the vertical anti-pressure-pulling performance of the single pile foundation;
FIG. 2 is a schematic view of a connection structure of a pile foundation compression resistance detection device and a main beam;
fig. 3 is a schematic view of a connection structure of the uplift detection device of the pile foundation and the pile foundation to be detected.
Reference numerals: 1. a pile foundation compression resistance detection device 11, a sleeper pile 12, an oil pressure gauge 13, a balancing weight 14, a first steel beam 15 and a first jack; 2. a pile foundation uplift detection device 21, a support table 22, a dial indicator 23, a second steel beam 24, a mechanical clamp or a steel bar 25 and a second jack; 3. a pile foundation to be tested; 4. a main beam.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
As shown in fig. 1, the invention provides a method for detecting vertical uplift resistance of a single pile foundation, which comprises the steps of performing vertical anti-compression detection on the single pile foundation and performing vertical uplift detection on the single pile foundation after the vertical anti-compression detection is completed. Specifically, the steps of the invention are as follows in sequence: leveling the pile top part of the pile foundation to be tested, gradually applying vertical pressure load to the pile foundation to be tested through a pile foundation compression resistance detection device, after each level of pressure load is completed, measuring and reading the settlement amount of the pile foundation to be tested, gradually unloading the vertical pressure load, measuring and reading the settlement amount of the pile foundation to be tested at each level, leveling the pile top part of the pile foundation to be tested again, gradually applying vertical tension load to the pile foundation to be tested through a pile foundation compression resistance detection device, after each level of tension load is completed, measuring and reading the pull-up deformation of the pile foundation to be tested, gradually unloading the vertical pressure load, and measuring and reading the pull-up deformation of the pile foundation to be tested at each level.
According to the invention, the compression resistance detection and the uplift resistance detection of the pile foundation to be detected can be realized simultaneously by leveling the pile top, loading step by step, unloading step by step, reading the reading of a pressure gauge or a tension gauge step by step and the like. Meanwhile, the uplift detection is set to be carried out after the anti-compression detection is finished, so that when the anti-compression or anti-compression detection is carried out on the pile foundation to be detected, too many jacks do not need to be arranged on the detection device at one time, and the pressure or the tension of the jacks on the top of the pile foundation to be detected is smaller, so that the anti-compression and anti-compression detection result is more accurate, and the pile top part of the pile foundation to be detected cannot be destructively influenced.
In actual work, the vertical compression resistance detection of the single pile foundation comprises the following steps,
s1, when the pile foundation 3 to be tested reaches the rest period required by the construction specification of the building engineering, and after the pile foundation is subjected to low strain detection, carrying out leveling treatment on the pile top of the pile foundation, so that the concrete quality and the section size of the pile top of the pile foundation 3 to be tested are equal to the design conditions (basically) of the pile body in the construction drawing;
in step S1, the step of leveling the pile top of the pile foundation includes the steps of:
a. chiseling off loose and damaged pile tops on the pile foundation 3 to be detected to expose the hard concrete surface of the pile foundation 3 to be detected;
b. leveling and cleaning the pile top surface of the pile foundation 3 to be detected, and ensuring that no water is accumulated on the pile top surface of the pile foundation 3 to be detected;
c. cutting off exposed main ribs of the pile top, which obstruct normal testing, on the pile foundation 3 to be tested;
d. when the pile top of the pile foundation 3 to be tested is connected with a bearing platform or a cushion layer of the building engineering, the large section impedance change exists at the pile top, which is equivalent to influence on a test signal, so that the pile top of the pile foundation 3 to be tested is disconnected with a concrete bearing platform; when the side surface of the pile top is connected with the cushion layer of the building engineering, the pile foundation 3 to be tested and the cushion layer are disconnected unless the test signal is not influenced.
The invention can process the pile top (pile head) of the pile foundation to be tested to meet the requirements of the compression and compression resistance detection, and can reduce the influence of the pile top on the compression and compression resistance detection, thereby directly improving the quality of the test signal.
S2, arranging a pile foundation compression resistance detection device 1 which is provided with a jack 5 and is used for applying vertical load to the pile foundation 3 to be detected on the pile foundation 3 to be detected, and applying vertical pressure load to the pile foundation to be lateral through the jack 5;
preferably, the load capacity of the vertical pressure load is converted by a calibration curve of the jack 5, and is measured and read by the oil pressure gauge 12, and a load-oil pressure value corresponding table is established on site. The calibration curve can help people to accurately control the pressure of the pile foundation to be tested, and the load-oil pressure value corresponding table can facilitate the field operation of personnel.
In actual operation, the pile foundation compression resistance detection device 1 comprises a pile foundation 3 to be detected, a sleeper pile 11, a first steel beam 14, a first jack 15, an oil pressure gauge 12 and a balancing weight 13 made of precast concrete, the sleeper piles 11 are symmetrically arranged on two sides of the pile foundation 3 to be detected, the first steel beam 14 is erected between the tops of the two sleeper piles 11, the first jack 15 is located between the top of the pile foundation and the middle of the first steel beam 14, the balancing weights 13 are multiple and are all erected at the upper end of the first steel beam 14, and the oil pressure gauge 12 is arranged on the pile foundation 3 to be detected.
In the technical scheme, the balancing weight 13 is used for applying a reverse force to the first steel beam 14, the oil pressure gauge 12 is used for measuring the pressure applied to the pile foundation 3 to be detected by the first jack 15, and the pile foundation compression resistance detection device 1 can be used for compression resistance detection of the pile foundation to be detected.
In actual operation, as shown in fig. 2, for convenience of operation, a main beam 4 may be further installed between the first steel beam 14 and the first jack 15, the first jack 15 is mainly used for pushing the first steel beam 14 (including the main beam 4), and 2 or 3 jacks of 5000kN may be adopted.
S3, when pressure load is applied to the pile foundation 3 to be tested, loading the pile foundation 3 to be tested by adopting a slow-speed load-maintaining method (namely step-by-step loading), adding the next stage of load after each stage of load is relatively stable, and measuring and reading the settlement of the pile foundation to be tested, wherein the interval time for measuring and reading the settlement of the pile foundation to be tested is after each stage of loading is finished;
in step S3, if the settling volume or the rising deformation of the pile foundation 3 to be tested in 1 hour is not greater than 0.1mm twice, it is determined that the settling volume of the current-stage pile foundation 3 to be tested has reached relatively stable, and the next-stage load can be applied to the pile foundation 3 to be tested. Therefore, people can accurately judge whether the pile foundation 3 to be tested is in a stable state, and then help people judge whether a next-stage load needs to be applied.
Preferably, in step S3, the load applied to each stage is 1/8 of the design limit bearing capacity, the load added to the first stage is 1/4 of the characteristic value of the bearing capacity, and the next stage of load cannot be applied until the compressive testing of the pile foundation reaches the maximum applied load value after the load of each stage is relatively stable; after each stage of applied pressure load is finished, measuring and reading the settlement amount or the rising deformation amount of the pile top at 5min, 15min, 30min, 45min and 60min in sequence, and then measuring and reading the settlement amount or the rising deformation amount of the pile top once every 30 min.
Therefore, the stability of each stage of load is improved by strictly controlling the load applying amount of each stage, and meanwhile, the time for measuring and reading the settlement of the pile top is strictly controlled, so that people can be helped to more accurately observe the influence of pressure or tension on the pile foundation to be measured.
And S4, after the compression resistance detection of the pile foundation reaches the maximum applied load value, unloading the load in the step S3 in a grading mode, wherein during unloading, the unloading value of each grade is twice of the loading value, the load is measured and read once every 15min after unloading, the load is read once every 30min after reading twice, then the load of the first grade is unloaded, and the load is measured and read once every 3h after all the loads are unloaded.
In actual work, the vertical uplift resistance detection of the single pile foundation comprises the following steps,
k1, in a rest period required by construction specifications of the building engineering, after the pile foundation 3 to be detected is subjected to vertical compression resistance detection, leveling the pile top of the pile foundation to be detected again, so that the concrete quality and the section size of the pile top of the pile foundation 3 to be detected are equal to the design conditions (basically) of the pile body in the construction drawing;
in the step K1, the step S1 may be referred to as a method of leveling the pile top of the pile foundation to be tested, and the step K1 may be referred to as a method of leveling the pile top of the pile foundation to be tested and the step S1.
K2, arranging a pile foundation uplift detection device 2 which is provided with a jack 5 and is used for applying vertical drawing force to the pile foundation 3 to be detected on the pile foundation 3 to be detected, and applying vertical tension load to the foundation pile through the jack 5;
pile foundation resistance to plucking detection device 2 is including the pile foundation 3 that awaits measuring, a supporting bench 21, second steel crossbeam 23 and percentage table 22, a supporting bench 21 has two and symmetrical distribution in 3 both sides of pile foundation that awaits measuring, second steel crossbeam 23 is located 3 tops of pile foundation that awaits measuring, all install second jack 25 separately on two supporting benches 21, second steel crossbeam 23 both sides are connected respectively to the output of two second jacks 25, be connected with mechanical fixture or reinforcing bar 24 between 23 middle parts of second steel crossbeam and the pile foundation 3 that awaits measuring, percentage table 22 has a plurality ofly and installs in the pile body both sides of pile foundation 3 that awaits measuring.
In actual work, as an optimal scheme, a balancing weight can be placed on the second steel cross beam 23 and used for providing a reverse force, the jack is used for applying a pulling force on the first steel cross beam 14 and further applying a pulling force on a pile foundation to be detected, the dial indicator 22 is used for measuring the rising deformation applied on the pile foundation 3 to be detected, and through the pile foundation uplift detection device 1, the pile foundation uplift detection device can be used for carrying out uplift detection on the pile foundation to be detected.
In actual operation, the support platform 21 of the invention can be a reaction pile or a natural foundation, and when the anti-pulling detection is carried out on the pile foundation 3 to be detected, the reaction pile or the natural foundation is used for providing reaction; the second steel beam 23 on the pile-foundation uplift detection device 2 can also be called a reaction beam, and in order to improve the detection accuracy, the gravity center of the reaction beam coincides with the central line of the pile foundation 3 to be detected, preferably, the support platform 21 adopts a reaction pile, and the gravity centers of the fulcrums at two sides of the reaction beam coincide with the central line of the reaction pile.
During actual operation, the second jack 25 is placed between the two ends of the reaction beam and the reaction pile or the natural foundation for applying a pulling force (i.e. for loading), and the upward pulling deformation of the pile foundation 3 to be tested is obtained by measuring the dial indicators 22 placed on the two sides of the pile body (concrete). According to the actual situation on site, the supporting platform 21 (such as a counterforce beam) is connected with the pile top of the pile foundation 3 to be tested in two modes of a mechanical clamp and a steel bar welding mode.
K3, when applying a tensile load to the pile foundation 3 to be tested, loading by adopting a slow load maintaining method (namely step-by-step loading), adding the next stage of load after each stage of load is relatively stable, and measuring and reading the rising deformation of the pile foundation to be tested, wherein the interval time for measuring and reading the rising deformation of the pile foundation to be tested is after each stage of loading is finished;
in step K3, if the settling volume or the rising deformation of the pile foundation 3 to be tested in 1 hour is not greater than 0.1mm twice, it is determined that the settling volume of the current-stage pile foundation 3 to be tested has reached relatively stable, and the next-stage load can be applied to the pile foundation 3 to be tested. Therefore, people can accurately judge whether the pile foundation 3 to be tested is in a stable state, and then help people judge whether a next-stage load needs to be applied.
And K4, when the termination detection condition of the vertical uplift detection is met, the detection is terminated, and then the pile foundation 3 to be detected is unloaded and read and recorded.
In actual work, when the compression resistance of the pile foundation to be detected is detected, the compression resistance or the uplift resistance of the pile foundation to be detected can be detected by adopting the existing compression resistance detection device or uplift resistance detection device, or by adopting the compression resistance detection device or uplift resistance detection device provided by the invention.
In order to reduce the influence of the vertical pressure load on the pile foundation to be measured, thereby improving the measurement accuracy of the vertical pressure load, when the vertical pressure load is applied, if one of the following three conditions occurs, the loading is terminated:
a. under the action of a certain level of load, the settlement of the pile foundation 3 to be detected is 5 times of that of the previous level of load, and the total settlement of the pile top exceeds 40 mm;
b. under the action of a certain level of load capacity, the settlement of the pile foundation 3 to be detected is 2 times larger than that of the previous level under the action of load, and the pile foundation is not relatively stable after 24 hours;
during actual work, the settlement of the pile foundation 3 to be measured reaches the relatively stable standard as follows: the settlement amount or the rising deformation amount of the pile foundation 3 to be measured in 1 hour is not more than 0.1mm continuously twice.
c. The design maximum applied load has been reached.
Preferably, in order to enable people to more accurately measure and read the settlement amount and the rising deformation amount of the pile foundation to be measured, in step S3, the maximum applied load value is twice of the characteristic value of the designed bearing capacity; in step K5, the destructive test coupon does not read the unload rebound variable. .
When a tensile load is applied, the loading is stopped if one of the following four conditions occurs:
k5.1: under the action of a certain level of load, the upward pulling amount of the pile top is 5 times larger than that under the action of the previous level of upward pulling load;
k5.2: controlling the pulling amount of the pile top according to the pulling amount of the pile top, and when the accumulated pulling amount of the pile top exceeds 100 mm;
k5.3: controlling according to the tensile strength of the steel bar, wherein the pulling load on the pile top reaches 0.9 time of the standard value of the strength of the steel bar;
k5.4: and for the pile foundation to be tested which is subjected to acceptance sampling detection, the maximum upper pulling load value of the design requirement is reached.
In actual operation, when compiling the inspection report, the inspector should pay attention to the normalization of the inspection report. In practice, the following problems should be mainly addressed:
a. original recording: including the original observation, calculation and data derivation, should be true and reliable, and the original record should not be the 'original' record of re-correcting. The original record is in a uniform recommended format as much as possible.
b. The use of the measurement unit shall adopt the legal measurement unit, and pay attention to several principles: firstly, the symbol principle is preferably adopted, secondly, the Chinese character name or the symbol of the metering unit must be taken as a whole and cannot be detached for use, and thirdly, the Chinese character name and the symbol of the metering unit cannot be mixed for use.
c. Data processing: the data processing method of the inspection result can be generally processed according to two standard requirements of 'representation method and judgment method of limit value' and 'rule of data modification', and attention is paid to the processing method of special data.
d. And (4) testing results and testing conclusions: when the measured value in the inspection result is quite close to the standard value but judged to be unqualified according to the comparison method of the full value or the comparison method of the trimming value, the measured value should be retested for several times according to the same condition for the sake of caution, and the average value is taken; or other detection methods are used for checking the reproducibility degree of the compound.
The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.
Claims (10)
1. A method for detecting the vertical uplift resistance of a single pile foundation comprises a pile foundation (3) to be detected which is composed of a pile top and a pile body, and is characterized by comprising the steps of carrying out vertical uplift detection on the single pile foundation and carrying out vertical uplift detection on the single pile foundation after the vertical uplift detection is finished, wherein,
the vertical compression resistance detection of the single pile foundation comprises the following steps,
s1, when the pile foundation (3) to be tested reaches the rest period required by the construction specification of the building engineering, and after the pile foundation is subjected to low strain detection, the pile top of the pile foundation is subjected to leveling treatment, so that the concrete quality and the section size of the pile top of the pile foundation (3) to be tested are equal to the design conditions of the pile body in the construction drawing;
s2, arranging a pile foundation compression resistance detection device (1) which is provided with a jack (5) and is used for applying vertical load to the pile foundation (3) to be detected on the pile foundation (3) to be detected (the prior art), and applying vertical pressure load to the pile foundation to be detected through the jack (5);
s3, when pressure load is applied to the pile foundation (3) to be tested, loading the pile foundation (3) to be tested by adopting a slow-speed load-maintaining method, adding the next stage of load after each stage of load is relatively stable, and measuring and reading the settlement of the pile foundation to be tested, wherein the interval time for measuring and reading the settlement of the pile foundation to be tested is the time after each stage of loading is finished;
s4, after the pile foundation compression resistance detection reaches the maximum applied load value, the load in the step S3 is unloaded in a grading mode, when the load is unloaded, the unloading value of each grade is twice of the loading value, the load is measured and read once every 15min after the load is unloaded, the load is read once every 30min after the load is read twice, then the load of the first grade is unloaded, and the load is measured and read once every 3h after the load is completely unloaded;
the vertical uplift resistance detection of the single pile foundation comprises the following steps,
k1, in a rest period required by construction specification of the building engineering, after the pile foundation (3) to be detected is subjected to vertical compression resistance detection, flattening the pile top of the pile foundation to be detected again, so that the concrete quality and the section size of the pile top of the pile foundation (3) to be detected are equal to the design conditions of the pile body in the construction drawing;
k2, arranging a pile foundation anti-pulling detection device (2) which is provided with a jack (5) and is used for applying vertical pulling force to the pile foundation (3) to be detected on the pile foundation (3) to be detected, and applying vertical pulling force load to the foundation pile through the jack (5);
k3, when a tensile load is applied to the pile foundation (3) to be tested, loading by adopting a slow load maintaining method, adding the next level of load after each level of load is relatively stable, and measuring and reading the rising deformation of the pile foundation to be tested, wherein the interval time for measuring and reading the rising deformation of the pile foundation to be tested is the time after each level of loading is finished;
and K4, when the termination detection condition of the vertical uplift detection is met, the detection is terminated, and then the pile foundation (3) to be detected is unloaded and read and recorded.
2. The method for detecting the vertical anti-drawing performance of the monolithic pile foundation according to claim 1, wherein in step S2, the load capacity of the vertical pressure load is converted by a calibration curve of the jack (5), and is measured and read by an oil pressure gauge (12), and a load-oil pressure value correspondence table is established on site.
3. The method for detecting the vertical pressure-pulling resistance of the single pile foundation according to claim 2, in step S2, the pile foundation compression resistance detection device (1) comprises a pile foundation (3) to be detected, a sleeper pile (11), a first steel beam (14), a first jack (15) and an oil pressure gauge (12), and a balancing weight (13) made of precast concrete, sleeper piles (11) are symmetrically arranged on two sides of the pile foundation (3) to be tested, a first steel cross beam (14) is erected between the tops of the two sleeper piles (11), a first jack (15) is positioned between the top of the pile foundation and the middle part of the first steel cross beam (14), a plurality of balancing weights (13) are erected on the upper end of the steel cross beam (4), the balancing weights (13) are used for applying reverse force to the first steel cross beam (14), an oil pressure gauge (12) is arranged on the pile foundation (3) to be tested, the pressure measuring device is used for measuring the pressure applied by the first jack (15) to the pile foundation (3) to be measured.
4. The method for detecting the vertical uplift resistance of the single pile foundation according to claim 3, wherein in the steps S3 and K3, if the settlement or the rising deformation of the pile foundation (3) to be detected within 1 hour is not more than 0.1mm twice, the settlement of the pile foundation (3) to be detected at the current stage is considered to be relatively stable, and the next stage of load can be applied to the pile foundation (3) to be detected.
5. The method for detecting the vertical uplift resistance of the single pile foundation according to claim 4, wherein in the step S1 and the step K1, the method for flattening the pile top of the pile foundation comprises the following steps:
a. chiseling off loose and damaged pile tops on the pile foundation (3) to be tested to expose the hard concrete surface of the pile foundation (3) to be tested;
b. leveling and cleaning the pile top surface of the pile foundation (3) to be detected, and ensuring that no water is accumulated on the pile top surface of the pile foundation (3) to be detected;
c. cutting off exposed main ribs of the pile top, which obstruct normal testing, on the pile foundation (3) to be tested;
d. when the pile top of the pile foundation (3) to be tested is connected with a bearing platform or a cushion layer of the building engineering, the pile top of the pile foundation (3) to be tested is disconnected with the concrete bearing platform; when the side surface of the pile top is connected with a cushion layer of the building engineering, the pile foundation (3) to be tested and the cushion layer are disconnected unless the test signal is not influenced.
6. The method for detecting the vertical uplift resistance of the single pile foundation according to any one of claims 1 to 5, wherein in the steps S3 and K3, the applied load capacity of each stage is 1/8 of the design limit bearing capacity, the adding amount of the first stage is 1/4 of the characteristic value of the bearing capacity, the next stage of load can not be applied until the compression detection of the pile foundation reaches the maximum applied load value, and the loading is stopped; after each stage of applied pressure load is finished, measuring and reading the settlement amount or the rising deformation amount of the pile top at 5min, 15min, 30min, 45min and 60min in sequence, and then measuring and reading the settlement amount or the rising deformation amount of the pile top once every 30 min.
7. The method for detecting the vertical anti-pulling performance of the single pile foundation according to claim 6, wherein when the vertical pressure load is applied, the loading is stopped if one of the following three conditions occurs:
a. under the action of a certain level of load, the settlement of the pile foundation (3) to be detected is 5 times of that of the previous level of load, and the total settlement of the pile top exceeds 40 mm;
b. under the action of a certain level of load capacity, the settlement of the pile foundation (3) to be detected is 2 times greater than that of the previous level under the action of load, and the pile foundation is not relatively stable after 24 hours;
c. the design maximum applied load has been reached.
8. The method for detecting the vertical uplift resistance of the single pile foundation according to claim 7, wherein in the step K2, the pile foundation uplift detection device (2) comprises the pile foundation (3) to be detected, a supporting platform (21), a second steel beam (23) and a dial indicator (22), the supporting platform (21) is provided with two supporting platforms which are symmetrically distributed on two sides of the pile foundation (3) to be detected, the second steel beam (23) is located above the pile foundation (3) to be detected, the two supporting platforms (21) are respectively provided with a second jack (25), the output ends of the two second jacks (25) are respectively connected with two sides of the second steel beam (23), a mechanical clamp or a steel bar (24) is connected between the middle part of the second steel beam (23) and the pile foundation (3) to be detected, and the dial indicator (22) is provided with a plurality of supporting platforms which are arranged on two sides of the pile body of the.
9. The method for detecting the vertical anti-pulling performance of the monolithic pile foundation according to claim 8, wherein in step S3, the maximum applied load value is twice of the design bearing capacity characteristic value; in step K5, the destructive test coupon does not read the unload rebound variable.
10. The method for detecting the vertical compression and pull resistance of the single pile foundation according to claim 9, wherein when a vertical tensile load is applied, the loading is terminated if one of the following four conditions occurs:
k5.1: under the action of a certain level of load, the upward pulling amount of the pile top is 5 times larger than that under the action of the previous level of upward pulling load;
k5.2: controlling the pulling amount of the pile top according to the pulling amount of the pile top, and when the accumulated pulling amount of the pile top exceeds 100 mm;
k5.3: controlling according to the tensile strength of the steel bar, wherein the pulling load on the pile top reaches 0.9 time of the standard value of the strength of the steel bar;
k5.4: and for the pile foundation to be tested which is subjected to acceptance sampling detection, the maximum upper pulling load value of the design requirement is reached.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112502206A (en) * | 2020-12-29 | 2021-03-16 | 福建汇达建筑工程有限公司 | Construction engineering foundation pile detection method |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4783701B2 (en) * | 2006-09-13 | 2011-09-28 | 多摩火薬機工株式会社 | Bearing capacity test method and test equipment for underground buried pile |
| CN105040749A (en) * | 2015-07-24 | 2015-11-11 | 上海港湾工程质量检测有限公司 | Pile foundation pulling resistance and compression resistance test system and test method |
| CN205954716U (en) * | 2016-08-08 | 2017-02-15 | 镇江市建科工程质量检测中心有限公司 | A counterforce device for foundation pile resistance to compression static test |
| CN206512763U (en) * | 2017-02-22 | 2017-09-22 | 中国电力工程顾问集团西北电力设计院有限公司 | A kind of bored concrete pile vertically pulling-resistant pilot system |
| CN109505317A (en) * | 2018-10-29 | 2019-03-22 | 建研地基基础工程有限责任公司 | A kind of resistance to compression of high stake, resistance to plucking and horizontally loading test equipment |
| CN209686465U (en) * | 2018-12-20 | 2019-11-26 | 中国建筑西北设计研究院有限公司 | A kind of load test system using water tank as loading system |
-
2020
- 2020-05-26 CN CN202010455560.1A patent/CN111622276A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4783701B2 (en) * | 2006-09-13 | 2011-09-28 | 多摩火薬機工株式会社 | Bearing capacity test method and test equipment for underground buried pile |
| CN105040749A (en) * | 2015-07-24 | 2015-11-11 | 上海港湾工程质量检测有限公司 | Pile foundation pulling resistance and compression resistance test system and test method |
| CN205954716U (en) * | 2016-08-08 | 2017-02-15 | 镇江市建科工程质量检测中心有限公司 | A counterforce device for foundation pile resistance to compression static test |
| CN206512763U (en) * | 2017-02-22 | 2017-09-22 | 中国电力工程顾问集团西北电力设计院有限公司 | A kind of bored concrete pile vertically pulling-resistant pilot system |
| CN109505317A (en) * | 2018-10-29 | 2019-03-22 | 建研地基基础工程有限责任公司 | A kind of resistance to compression of high stake, resistance to plucking and horizontally loading test equipment |
| CN209686465U (en) * | 2018-12-20 | 2019-11-26 | 中国建筑西北设计研究院有限公司 | A kind of load test system using water tank as loading system |
Non-Patent Citations (2)
| Title |
|---|
| 中华人民共和国住房和城乡建设部: "《建筑基桩检测技术规范》", 31 December 2014 * |
| 潘洪科: "《基础工程》", 30 August 2015 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112502206A (en) * | 2020-12-29 | 2021-03-16 | 福建汇达建筑工程有限公司 | Construction engineering foundation pile detection method |
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