CN115233752A - Reverse self-balancing pile testing method based on double pile body load boxes - Google Patents
Reverse self-balancing pile testing method based on double pile body load boxes Download PDFInfo
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- 238000012360 testing method Methods 0.000 title claims abstract description 28
- 238000006073 displacement reaction Methods 0.000 claims abstract description 69
- 238000011068 loading method Methods 0.000 claims abstract description 61
- 238000012544 monitoring process Methods 0.000 claims abstract description 20
- 238000004873 anchoring Methods 0.000 claims abstract description 15
- 238000007789 sealing Methods 0.000 claims description 21
- 239000002689 soil Substances 0.000 claims description 12
- 238000010998 test method Methods 0.000 claims description 12
- 238000004364 calculation method Methods 0.000 claims description 10
- 230000009471 action Effects 0.000 claims description 8
- 230000006835 compression Effects 0.000 claims description 6
- 238000007906 compression Methods 0.000 claims description 6
- 229910000831 Steel Inorganic materials 0.000 claims description 3
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- 238000000034 method Methods 0.000 description 11
- 238000010586 diagram Methods 0.000 description 5
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D27/00—Foundations as substructures
- E02D27/10—Deep foundations
- E02D27/12—Pile foundations
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
- E02D5/52—Piles composed of separable parts, e.g. telescopic tubes ; Piles composed of segments
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/74—Means for anchoring structural elements or bulkheads
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2600/00—Miscellaneous
- E02D2600/10—Miscellaneous comprising sensor means
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2600/00—Miscellaneous
- E02D2600/30—Miscellaneous comprising anchoring details
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Abstract
The invention discloses a reverse self-balancing pile testing method based on a double-load box of a pile body, which comprises the steps of determining an upper balance point and a lower balance point, and dividing a pile into an upper section pile, a middle section pile and a lower section pile; respectively arranging a load box at the top of the upper section of pile and between adjacent sections of piles, and sequentially marking as a first load box, a second load box and a third load box; the load boxes comprise jacks and pressure sensors; the top of the upper section pile is provided with a counter-force anchoring system which comprises a counter-force end plate and an anchor rope for anchoring and connecting the counter-force end plate and the middle section pile; arranging a displacement monitoring system for respectively monitoring the displacement of the upper section pile, the middle section pile and the lower section pile; sequentially loading a third load box, a second load box and a first load box, and obtaining the positive limit bearing capacity of each section of pile according to a load displacement curve loaded each time; and then adding the bearing capacity values to obtain the total ultimate bearing capacity of the pile foundation. The invention avoids the problem of non-coincidence of pile body loading and pile top loading balance points in the prior art, and the obtained pile foundation bearing capacity is more in line with the actual situation.
Description
Technical Field
The invention belongs to the field of civil engineering, relates to a reverse self-balancing pile testing method technology, and particularly relates to a reverse self-balancing pile testing method based on a pile body double-load box.
Background
At present, the static load test is considered at home and abroad to be the most accurate and reliable test method for detecting the bearing capacity of the foundation pile. According to different counter-force systems in engineering, static load tests are mainly divided into three types, namely a pile loading method, an anchor pile method and a self-balancing method. The pile loading method is the most reliable method for detecting the bearing capacity of the foundation pile. The counter force of the static load test is provided by a heavy object, but the construction site condition is limited, and higher installation and transportation cost is required; the anchor pile method is to use the anchor pile as a counter-force system, and the method is mainly used for testing the bearing capacity of the large-diameter cast-in-place pile, and usually four or more anchor piles are needed, so that the test cost is increased; the self-balancing method does not need a loading platform and an anchor pile counter-force system, but has extremely high technical requirements on construction technicians, because whether the test can be successful or not is often in a big relation with the correct selection of a 'balance point', and the test load borne by the pile body is only half of the designed load limit bearing capacity, so that the real strength of the pile body of the test pile under the limit bearing capacity and the uncertainty of the value of the negative frictional resistance to the positive frictional resistance cannot be measured. Therefore, a reverse self-balancing pile testing method is provided, and a pile top loading device is added on the basis of the self-balancing pile testing method.
The reverse self-balancing method has the advantages that a loading platform and an anchor pile counter-force system are not needed, and the technical problem that the negative friction of the upper-section pile of the self-balancing test pile needs to be converted into the positive friction is solved.
However, the reverse self-balancing pile test method has a problem that the upper pile section is easily pulled upwards when the pile top is loaded, because the requirements of the pile body loading and the pile top loading on the position of the balance point are different, the pile body loading is suitable for calculating the position of the balance point which is lower, and the pile top loading is suitable for calculating the position of the balance point. Meanwhile, due to the fact that geological survey data are inaccurate, errors exist in the installation position of the load box and the like, the limit cannot be reached simultaneously when the pile body loads the upper pile and the lower pile, and therefore the obtained test result is smaller than the actual test result.
As shown in fig. 1, two sets of loading devices are arranged in the reverse self-balancing pile testing method, namely, pile body loading and pile top loading. The change of the loading sequence causes the distribution of the side frictional resistance of the pile body and the position of the neutral point to change, as shown in the figure, when the pile body is loaded, the
Q fd2 + ＝A p q r ，Q fu - The upper pile section is subjected to vertical downward negative frictional resistance, Q fd1 + The lower section of the pile is subjected to vertical and upward positive frictional resistance, Q fd2 + The lower section of the pile is subjected to vertical upward end resistance, and the requirement of Q is met for achieving balance fu _ +G u ＝Q fd1 + +Q fd2 + The position of the load box is deviated, the counterforce of the pile end of the lower section pile can be exerted more completely, so that the proper position of the load box is deviated; when pile top is loaded, Q fu + The upper section of the pile is subjected to vertical and upward positive frictional resistance, Q fd _ The lower section of the pile is subjected to vertical downward negative frictional resistance, wherein Q fd1 + +Q fd2 + >Q fd _ Therefore, the balance point can not meet the loading of the pile top when the pile body loading is met; a technology is also urgently needed to eliminate the defects, so that the obtained ultimate bearing capacity of the pile foundation is closer to the real ultimate bearing capacity, and the application of a reverse self-balancing pile test method in foundation pile engineering is expected to be promoted.
Disclosure of Invention
Aiming at the problem that the positions of balance points required by pile body loading and pile top loading in a reverse self-balancing pile testing method are inconsistent, the invention provides a reverse self-balancing pile testing method based on a pile body double-load box.
In order to solve the technical problems, the invention adopts the following technical scheme:
the reverse self-balancing pile testing method based on the double loading boxes of the pile body is characterized by comprising the following steps of:
step 1, determining an upper balance point and a lower balance point through calculation or experience judgment according to geological data, and dividing a pile into an upper section pile, a middle section pile and a lower section pile, wherein the two balance points are respectively positioned between the two adjacent sections of piles;
And 7, loading a pile top, loading a jack in the first load box to force the upper-section pile and the middle-section pile to move oppositely, drawing a load displacement curve graph of the upper-section pile and the middle-section pile according to the displacement of the upper-section pile and the middle-section pile obtained by the displacement monitoring system and the force obtained by the pressure sensor in the first load box, and obtaining the positive limit bearing capacity Q of the upper-section pile through curve trend uu + And the negative limit bearing capacity Q of the middle section pile um - ；
And 7, calculating the vertical compression-resistant total ultimate bearing capacity of the pile, wherein the calculation formula is as follows:
Q press and press For the vertical resistance to compression total ultimate bearing capacity of stake, G is the total dead weight of stake.
Compared with the prior art, the invention has the following effective effects:
according to the invention, the problem that the positions of the balance points required by pile body loading and pile top loading in the traditional reverse self-balancing pile test method are inconsistent is solved by selecting the mode that two pile body jacks are arranged at two balance points, the ultimate bearing capacity of the pile foundation is obtained by three-time loading segmentation, and then the ultimate bearing capacity of the total pile foundation is calculated, so that the problem that the balance points of pile body loading and pile top loading are not coincident in the original technical scheme is avoided, the obtained bearing capacity of the pile foundation is more consistent with the real ultimate bearing capacity of the pile foundation, and more accurate design basis is provided for the engineering pile.
Drawings
Fig. 1 is a force diagram of a reverse self-balancing method in the prior art.
Fig. 2 is a structural schematic diagram of a reverse self-balancing pile testing device based on a pile body double-load box in the embodiment of the invention.
Fig. 3 is a schematic diagram of pile stress when the third load box is loaded in the embodiment of the invention.
Fig. 4 is a schematic diagram of pile stress when the second load box is loaded in the embodiment of the invention.
Fig. 5 is a schematic diagram of the pile force applied when the first load box is loaded in the embodiment of the invention.
1-a counter-force end plate; 2-dial indicator; 3-a hydraulic oil station; 4-a data acquisition system; 5-upper pile section; 6, anchor cables; 7-a displacement rod; 8-sealing an end plate at the bottom of the upper section pile; 9-sealing an end plate on the top of the middle section pile; 10-steel shaft bolt; 11-middle section pile; 12-middle section pile bottom sealing end plate; 13-a third load box; 14-lower pile top sealing end plate; 15-lower section of pile; 16-a jack; 17-a pressure sensor; 18-upper pile top end sealing plate, 19-second load box and 20-first load box.
Detailed Description
The embodiments of the present invention will be described in further detail with reference to the drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.
As shown in fig. 2, the invention provides a reverse self-balancing pile testing device based on a pile body double-load box, which comprises a pile, a reverse anchoring system, a loading system and a displacement monitoring system; the piles comprise upper piles 5, middle piles 11 and lower piles 15, and end-sealing plates are arranged at the tops of the upper piles 5, the bottoms of the upper piles 5, the tops of the middle piles 11, the bottoms of the middle piles 11 and the tops of the lower piles 15;
the loading system comprises three load boxes and a hydraulic oil station 3, each load box comprises a jack 16 and a pressure sensor 17 which are arranged in a stacked mode, and the pressure sensors 17 are generally arranged at the free telescopic ends of the jacks 16 and used for measuring the actual loading force of the jacks 16; the jacks 16 of the three load boxes are connected with the hydraulic oil station 3 through an oil way control system, the loading and unloading of each jack 16 are controlled through the hydraulic oil station 3, and how to control the loading and unloading of each jack 16 has no influence on solving the technical problem of the invention; the second load box 19 is arranged between the upper-section pile 5 and the middle-section pile 11, and is specifically arranged on the middle-section pile top end sealing plate 9 and between the upper-section pile bottom end sealing plate 8; the third load box is arranged between the middle section pile 11 and the lower section pile 15, and is specifically arranged between the lower section pile top end sealing plate 14 and the middle section pile bottom end sealing plate 12.
The counter-force anchoring system comprises a counter-force end plate 1 and a plurality of anchor cables 6, the counter-force end plate 1 is arranged at the top of the first load box, the tops of the anchor cables 6 are fixedly connected with the counter-force end plate 1, and the lower ends of the anchor cables freely penetrate through the upper-section pile 5 and then are fixed on the sealing end plate 9 at the top of the middle-section pile; through holes for the anchor cable 6 to freely pass through are formed in the upper-section pile top end sealing plate 18 and the upper-section pile bottom end sealing plate 8.
As a preferred embodiment, the anchor cables 6 are uniformly distributed around the first load box, so as to prevent unbalanced loading during the loading process.
As a preferred embodiment, the lower end of the anchor cable 6 is fixed at the bottom of the middle-section pile top end sealing plate 9 through a steel shaft plug 10, so that the fixing is simple and convenient, and the anchoring requirement can be met.
It should be noted that the pile in the invention can be a model pile in a model test or an engineering pile, and the invention is only used for illustrating a principle method, so that the installation sequence of the load box and the displacement monitoring system can be selected according to the requirement, and is not limited to a certain specific form.
The movement monitoring system comprises a data acquisition system 4, four displacement rods 7 and a dial indicator 2 which is arranged at the tops of the corresponding displacement rods 7 and used for measuring the movement displacement of the displacement rods 7, wherein the first displacement rod freely penetrates through the upper section of pile 5 and then is fixed on an upper section of pile bottom end sealing plate 8 and used for measuring the pile bottom displacement of the upper section of pile 5; the second displacement rod freely penetrates through the upper section pile 5 and then is fixed on the middle section pile top end sealing plate 9 and used for measuring the pile top displacement of the middle section pile 11; the third displacement rod freely penetrates through the upper-section pile 5 and the middle-section pile 11 and then is fixed on the middle-section pile bottom sealing end plate 12 and used for measuring the pile bottom displacement of the middle-section pile 11; and the fourth displacement rod freely penetrates through the upper-section pile 5 and the middle-section pile 11 and then is fixed on the lower-section pile top end sealing plate 14 for measuring the pile top displacement of the lower-section pile 15.
Four percentage table 2 hang on external member or set up the independent support fixed, four displacement poles 7 move up and down along with the closed end board of fixing separately in the loading process, can read every displacement pole 7 through percentage table 2 and move the distance up and down, be the displacement of corresponding section stake promptly.
As shown in fig. 3 to 4, the present invention provides a reverse self-balancing pile testing method based on the above-mentioned reverse self-balancing pile testing device, including the following steps:
step 1, determining an upper balance point and a lower balance point through calculation or empirical judgment according to geological data, dividing the pile into three sections, namely an upper section pile 5, a middle section pile 11 and a lower section pile 15, wherein the two balance points are respectively positioned between the two adjacent sections of piles;
And 7, calculating the vertical compression-resistant total ultimate bearing capacity of the pile, wherein the calculation formula is as follows:
Q press and press For the vertical resistance to compression total ultimate bearing capacity of stake, G is the total dead weight of stake.
As a preferred embodiment, in step 1, the two equilibrium points are determined as follows:
step 1.1, firstly, the pile is preliminarily divided into an upper section pile and a lower section pile, and a first balance point is determined through a balance point calculation formula which is as follows:
in the above formula, the first and second carbon atoms are,
in the above formula, i represents the number of layered soil layers around the pile, λ i Representing the weighting correction coefficient of the soil layer around the upper pile, taking 0.8 of cohesive soil and silt and 0.7 of sandy soil; u denotes the pile body circumference, l i Representing the length of the corresponding segment of the pile's surrounding soil, q ik Is represented by i The standard value of frictional resistance between the side of the pile with the corresponding length and the soil layer, the dead weight of the pile at the upper section on G, the sectional area of the pile end on Ap, the allowable bearing capacity of the soil at the pile end on qr and the left summation formula
The pile side resistance summation and the right side summation formula of the upper pile are expressed
The pile side resistance summation of the lower pile is shown.
Step 1.2, after a first balance point is obtained by calculating the length of the upper section pile, selecting a point in the middle of the preliminary lower section pile as a second balance point according to an empirical value (for example, the second balance point selects the length of one third to two thirds of the preliminary lower section pile, the specific position of the balance point is not particularly important, and the calculation inaccuracy of the first balance point can be corrected enough only by setting the second balance point), and dividing the preliminary lower section pile into two sections, so that three sections of upper section pile, middle section pile and lower section pile are obtained.
It should be noted that, the first balance point calculation method may refer to the highway bridge foundation and foundation design specification (JTG D63-2007).
As a preferred embodiment, the central axes of the jacks and the pressure sensors in the three load boxes are coincident with the central axis of the pile.
As a preferred embodiment, the pressure sensor is a cylindrical pressure sensor with the offset load resisting capacity.
In the step 5 to the step 7, the jack 16 in the load box is loaded in a graded loading mode, and each grade of loading is 1/10-1/15 of the estimated limit load.
As a preferred embodiment, in step 5 to step 7,
the displacement of each hour does not exceed 0.1mm and continuously occurs twice, which is considered to be relatively stable, and the next stage of load is added; when one of the download conditions occurs, the loading can be terminated;
(1) The limit loading value has been reached;
(2) Under the action of a certain level of load, the displacement of the pile is 5 times of that of the pile under the action of the previous level of load;
(3) Under the action of a certain level of load, the displacement of the pile is 2 times larger than that of the pile under the action of the previous level of load, and the pile is not relatively stable for 24 hours;
(4) The cumulative amount of pull-up exceeds 100mm.
The above embodiments are merely illustrative of the present invention and are not to be construed as limiting the invention. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that various combinations, modifications or equivalents may be made to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention, and the technical solution of the present invention is covered by the claims of the present invention.
Claims (9)
1. The utility model provides a reverse self-balancing pile testing method based on two load boxes of pile body which characterized in that includes following steps:
step 1, determining an upper balance point and a lower balance point through calculation or experience judgment according to geological data, and dividing a pile into an upper section pile, a middle section pile and a lower section pile, wherein the two balance points are respectively positioned between the two adjacent sections of piles;
step 2, respectively arranging a load box at the top of the upper-section pile, between the upper-section pile and the middle-section pile, and between the middle-section pile and the lower-section pile, sequentially marking as a first load box, a second load box and a third load box, wherein each load box comprises a jack and a pressure sensor which are arranged in a stacked manner or a jack with a pressure sensor;
step 3, arranging a counter-force anchoring system at the top of the upper section of pile, wherein the counter-force anchoring system comprises a counter-force end plate arranged at the top of the first load box and an anchor rope for anchoring and connecting the counter-force end plate and the middle section of pile, and the anchor rope freely penetrates through the upper section of pile;
step 4, arranging a displacement monitoring system, and respectively monitoring the displacement of the upper section pile, the middle section pile and the lower section pile;
step 5, loading a pile body, loading a jack in a third load box to force the middle-section pile and the lower-section pile to move back to back, drawing a load displacement curve graph of the middle-section pile and the lower-section pile according to the displacement of the middle-section pile and the lower-section pile obtained by the displacement monitoring system and the force obtained by a pressure sensor in the third load box, and obtaining the negative limit bearing capacity Q of the middle-section pile through curve trend um - And the positive limit bearing capacity Q of the lower section pile ud + ；
Step 6, loading a pile body, loading a jack in a second load box, forcing the upper-section pile and the middle-section pile to move back to back, drawing a load displacement curve graph of the upper-section pile and the middle-section pile according to the displacement of the upper-section pile and the middle-section pile obtained by the displacement monitoring system and the force obtained by a pressure sensor in the second load box, and obtaining the negative limit bearing capacity Q of the upper-section pile through curve trend uu - And the positive limit bearing capacity Q of the middle section pile um + ；
And 7, loading a pile top, loading a jack in the first load box to force the upper-section pile and the middle-section pile to move oppositely, drawing a load displacement curve graph of the upper-section pile and the middle-section pile according to the displacement of the upper-section pile and the middle-section pile obtained by the displacement monitoring system and the force obtained by the pressure sensor in the first load box, and obtaining the positive limit bearing capacity Q of the upper-section pile through curve trend uu + And the negative limit bearing capacity Q of the middle section pile um - ；
And 7, calculating the vertical compression-resistant total ultimate bearing capacity of the pile, wherein the calculation formula is as follows:
Q pressing and pressing For the vertical resistance to compression total ultimate bearing capacity of stake, G is the total dead weight of stake.
2. The reverse self-balancing pile test method according to claim 1, wherein: in step 1, the two balance points are determined as follows:
step 1.1, firstly, the pile is preliminarily divided into an upper section of pile and a lower section of pile, and a first balance point is determined through a balance point calculation formula which is as follows:
in the above formula, i represents the number of layered soil layers around the pile, λ i Expressing the weighted correction coefficient of the upper pile circumference soil layer, u expressing the circumference of the pile body, l i Representing the length of the corresponding segment of the pile's surrounding soil, q ik Is represented by i The standard value of frictional resistance between the pile side and the soil layer with corresponding length is G, the dead weight of the upper pile is shown, ap is the sectional area of the pile end, qr is the allowable bearing capacity of the soil at the pile end, and the left summation formula
The pile side resistance summation and the right side summation formula of the upper pile are expressed
Showing pile side resistance summation of the lower pile;
and 1.2, after a first balance point is obtained by calculating the length of the upper section pile, selecting a point in the middle of the preliminary lower section pile as a second balance point according to an empirical value, and dividing the preliminary lower section pile into two sections, so as to obtain three sections of upper section piles, middle section piles and lower section piles.
3. The reverse self-balancing pile test method according to claim 1, wherein: the top of the lower section pile, the bottom of the middle section pile, the top of the middle section pile, the bottom of the upper section pile and the top of the upper section pile are all provided with end sealing plates; and the lower end of an anchor rope of the counter-force anchoring system freely penetrates through the anchor rope sleeve and then is fixed on the end sealing plate at the top of the middle-section pile.
4. The reverse self-balancing pile test method according to claim 3, wherein: move monitoring system and include four displacement poles and locate corresponding displacement pole top and be used for measuring the percentage table that the displacement pole removed the displacement, first displacement pole freely passes upper segment stake after-fixing on upper segment stake bottom end seal plate, second displacement pole freely passes upper segment stake after-fixing on middle segment stake top end seal plate, third displacement pole freely passes upper segment stake and middle segment stake after-fixing on middle segment stake bottom end seal plate, fourth displacement pole freely passes upper segment stake and middle segment stake after-fixing on lower segment stake top end seal plate.
5. The reverse self-balancing pile test method according to claim 3, wherein: and the lower end of the anchor cable is fixed on the end sealing plate at the top of the middle section pile through a steel shaft bolt.
6. The reverse self-balancing pile test method according to claim 1, wherein: the central axes of the jacks and the pressure sensors in the three load boxes are coincided with the central axis of the pile.
7. The reverse self-balancing pile test method according to claim 6, wherein: the pressure sensor is a cylindrical pressure sensor with unbalance loading resistance.
8. The reverse self-balancing pile test method according to claim 1, wherein: and 5, in the step 7, the jack in the load box is loaded in a graded loading mode, and each grade of loading is 1/10-1/15 of the estimated limit load.
9. The reverse self-balancing pile test method according to claim 1, wherein: in the step from the step 5 to the step 7,
the displacement of each hour does not exceed 0.1mm and continuously occurs twice, which is considered to be relatively stable, and the next stage of load is added; when one of the download conditions occurs, the loading can be terminated;
(1) The limit loading value has been reached;
(2) Under the action of a certain level of load, the displacement of the pile is 5 times of that of the pile under the action of the previous level of load;
(3) Under the action of a certain level of load, the displacement of the pile is 2 times larger than that of the pile under the action of the previous level of load, and the pile is not relatively stable for 24 hours;
(4) The cumulative amount of pull-up exceeds 100mm.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117344807A (en) * | 2023-10-20 | 2024-01-05 | 广州开发区建设工程检测中心有限公司 | Vertical bearing capacity device for detecting foundation pile and detection method thereof |
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| CN115233752B (en) | 2023-04-25 |
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