A method for optimizing the length of a precast pile in a pile foundation construction in a yellow flood plain

Abstract

The embodiment of the present application provides a method for optimizing the length of a precast pile in the construction of a pile foundation in a yellow flood plain, which comprises: obtaining stratum-related parameters corresponding to a building site in the yellow flood plain; dividing the building site into a plurality of experimental areas, carrying out pile testing in the plurality of experimental areas, and obtaining actual bearing capacity characteristic values of the pile foundation by static load testing; calculating single-pile bearing capacity characteristic values of the lengths of piles corresponding to a plurality of boreholes according to actual stratum-related parameters of the boreholes; comparing the calculated single-pile bearing capacity characteristic values with the actual bearing capacity characteristic values of the pile foundation in the plurality of experimental areas, inversely optimizing and adjusting the side friction and end resistance of the pile, and correcting stratum-pile foundation parameters corresponding to each borehole in combination with static sounding testing in the building site; calculating the bearing capacity characteristic values of the pile foundation of the boreholes according to the adjusted stratum-pile foundation parameters, and drawing a bearing capacity contour map of the pile foundation. The present application can save the amount of precast pile foundation and reduce construction costs.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the field of pile foundation treatment, in particular to a method for optimizing the length of precast piles in the construction of pile foundations in the Yellow River flood plain. BACKGROUND

[0002] Pile foundations are widely used and are effective engineering measures for improving the bearing capacity of foundations and reducing the settlement deformation of foundations. Commonly used pile types include precast reinforced concrete piles, prestressed reinforced concrete piles, drilled (driven) cast-in-place piles, hand-dug cast-in-place piles, and steel pipe piles.

[0003] However, in the Yellow River flood plain, where the main stratum is silty clay, silt, and silt, the current method of designing pile foundations with a uniform maximum pile length for the same area is still used. As a result, there is still a problem of high cost of pile foundations in the Yellow River flood plain. SUMMARY

[0004] To solve the above problems, the embodiment of the present application provides a method for optimizing the length of precast piles in the construction of pile foundations in the Yellow River flood plain, which sets different pile foundation lengths for different soil layers in the same area, thereby saving the cost of pile foundations.

[0005] Based on the above, the embodiment of the present application provides a method for optimizing the length of precast piles in the construction of pile foundations in the Yellow River flood plain, which includes:

[0006] Obtain the stratum-related parameters corresponding to the building site in the Yellow River flood plain, wherein the stratum-related parameters include at least one of the mechanical parameters of each soil layer in the building site, the pile side friction and end resistance of the precast pile, and the mechanical parameters at least include the thickness of the soil layer and the stratum bearing capacity;

[0007] Divide the building site into multiple experimental areas, perform pile testing in the multiple experimental areas, and obtain the actual bearing capacity characteristic value of the test pile foundation through static load testing, wherein the test pile foundation is prepared based on the stratum-related parameters;

[0008] According to the actual stratum-related parameters of the survey drill holes, calculate the single pile bearing capacity characteristic value of the corresponding pile length of the multiple drill holes, wherein the number of drill holes in the survey drill holes is multiple;

[0009] Compare the calculated single pile bearing capacity characteristic value with the actual bearing capacity characteristic value of the test pile foundation in the multiple experimental areas, and combine the static sounding test in the building site to inversely optimize and adjust the pile side friction and end resistance, and correct the stratum pile foundation parameters corresponding to each drill hole;

[0010] According to the adjusted stratum pile foundation parameters, the pile foundation bearing capacity characteristic values of the drill holes are calculated, and a pile foundation bearing capacity contour chart of each drill hole is drawn, which is used to represent the prefabricated piles with different pile lengths in different regions, wherein at least a safe area and a non-safe area are marked in the pile foundation bearing capacity contour chart, in the safe area, the pile foundation length of the preset pile indicated by the pile foundation bearing capacity contour chart is determined as the prefabricated pile length in construction, and in the non-safe area, the pile foundation length of the prefabricated pile indicated by the pile foundation bearing capacity contour chart is increased to a preset length, and the prefabricated pile with the preset length is determined as the prefabricated pile length in construction.

[0011] In the embodiment of the present application, the stratum associated parameters corresponding to the building site in the Yellow River Floodplain are obtained, the building site is divided into a plurality of experimental areas, pile tests are carried out in the plurality of experimental areas, and the actual bearing capacity characteristic values of the pile foundations of the test piles are obtained through static load tests; according to the actual stratum associated parameters of the survey drill holes, the single pile bearing capacity characteristic values of the corresponding pile lengths of the plurality of drill holes are calculated; the actual bearing capacity characteristic values of the pile foundations of the test piles in the plurality of experimental areas are compared, and the pile side friction and end resistance of the relatively discrete stratum are inversely optimized and adjusted in combination with the static sounding test in the building site, the stratum pile foundation parameters corresponding to each drill hole are corrected, the pile foundation bearing capacity characteristic values of the drill holes are calculated according to the adjusted stratum pile foundation parameters, and a pile foundation bearing capacity contour chart of each drill hole is drawn. In the embodiment of the present application, the actual bearing capacity characteristic values of the pile foundations of the test piles in the experimental areas are measured, and the single pile bearing capacity characteristic values of the corresponding pile lengths of the plurality of drill holes are calculated through the stratum associated parameters of the survey drill holes, the two are compared and analyzed, and the stratum pile foundation parameters corresponding to each drill hole are corrected in combination with the static sounding test, so as to generate pile foundations with different lengths according to the stratum pile foundation parameters, which avoids the way of designing pile foundations only according to the unified maximum pile length in the same region, saves the production cost of the pile foundation, and improves the accuracy of the prefabricated pile. Further, in the present application, the pile foundation bearing capacity contour chart is also used to represent the pile lengths of the prefabricated piles in different regions, and the staff can obtain the required prefabricated pile length in construction according to the pile foundation bearing capacity contour chart, which reduces the threshold for the staff to obtain the prefabricated pile, and greatly optimizes the process of obtaining the prefabricated pile length. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of the provided drawings.

[0013] Figure 1A flowchart is shown for the pile length optimization method for the precast pile in the Yellow River floodplain pile foundation construction in the embodiments of the present application.

[0014] Figure 2 A schematic diagram of the pile foundation bearing capacity contour map is shown in the embodiments of the present application. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0016] Figure 1 An optional flowchart of the pile length optimization method for the precast pile in the Yellow River floodplain pile foundation construction in the embodiments of the present application is shown. As shown in the figure, the pile length optimization method for the precast pile in the Yellow River floodplain pile foundation construction can specifically include: Figure 1

[0017] Step S11, obtaining stratum-related parameters corresponding to a building site in a Yellow River floodplain, wherein the stratum-related parameters include at least one of mechanical parameters of each soil layer in the building site, pile side friction of the precast pile and end resistance, and the mechanical parameters at least include soil layer thickness and stratum bearing capacity.

[0018] The stratum-related parameters corresponding to the building site in the Yellow River floodplain can be obtained by drilling (mainly by drilling), indoor experiment, static sounding experiment, etc. Through the above methods, the thickness of each soil layer in the building site in the Yellow River floodplain, the mechanical parameters such as stratum bearing capacity, the pile side friction of the precast pile and the end resistance can be basically found out, so as to generate a plurality of test pile foundations according to the above stratum-related parameters.

[0019] Optionally, the soil layer type in the Yellow River floodplain can be one or more of silty clay, silt and silty sand; accordingly, the thickness of each soil layer in the Yellow River floodplain is one or more of the thickness of silty clay, the thickness of silt and the thickness of silty sand.

[0020] Step S12, dividing the building site into a plurality of experimental areas, performing test piles in the plurality of experimental areas, and obtaining actual bearing capacity characteristic values of the test pile foundations through static load test, wherein the test pile foundations are prepared based on the stratum-related parameters.

[0021] In an optional embodiment, the step of preparing the test pile foundation based on the stratum-related parameters is:

[0022] ​Determine the size information of the pile foundation according to the stratum correlation parameters, wherein the size information comprises at least one of the following: pile length, pile inclination, plane torsion angle, inner and outer diameter size, and spatial coordinates of the pile top.

[0023] Generate the trial pile foundation based on the size information of the pile foundation.

[0024] Optionally, the static load experiment is used to measure the actual bearing capacity characteristic value of each trial pile foundation. The static load experiment refers to a test method in which a vertical pressure, a vertical uplift force or a horizontal thrust is applied to the top of the trial pile foundation in stages, and the settlement, uplift displacement or horizontal displacement of the top of the trial pile foundation over time is observed to determine the corresponding single-pile vertical compressive bearing capacity, single-pile vertical uplift bearing capacity or single-pile horizontal bearing capacity.

[0025] It should be noted that the Yellow River Floodplain is a plain located between the Haihe Plain and the North Huaihe Plain and formed by the Yellow River alluvium. Due to the long-term alluvium of the Yellow River, the main stratum in the plain is silty clay, silt and silty sand, but the distribution of silty clay, silt and silty sand is not uniform. Therefore, it is necessary to divide multiple experimental areas based on the building site of the Yellow River Floodplain, and then determine the different bearing capacities in different experimental areas by using trial piles, and combine the single-pile bearing capacity characteristic values obtained by drilling to correct the stratum pile foundation parameters corresponding to each drilling hole, and generate precast piles of different pile lengths based on the stratum pile foundation parameters to save the cost of pile foundations.

[0026] In an embodiment, the experimental area can be an experimental area with the same area size in the Yellow River Floodplain, or an experimental area with different areas in the Yellow River Floodplain. Among them, the soil layers in the same experimental area are as same as possible or similar to each other, so as to improve the accuracy of generating precast piles in the area subsequently.

[0027] Step S13, according to the actual stratum correlation parameters of the survey drilling hole, calculate the single-pile bearing capacity characteristic values of the pile length of the multiple drilling holes, wherein the number of drilling holes in the survey drilling hole is multiple.

[0028] That is, the stratum correlation parameters can be obtained through the survey drilling hole, and then the single-pile bearing capacity characteristic values of the pile length at the drilling hole position are determined based on the stratum correlation parameters of the survey drilling hole.

[0029] In addition, it should be noted that the construction position of the precast pile may not be the same as the position of the aforementioned drilling hole in the subsequent construction process, and the construction position set by the staff is specific. If the survey drilling hole position is not easy to set the trial pile foundation in the actual construction, the trial pile foundation can be treated as being staggered with the drilling hole position, and the best distance of the staggering is within 50m from the drilling hole position.

[0030] The actual bearing capacity characteristic value of the test pile foundation can include the pile side friction resistance q sik (kPa) and the end resistance q pk (kPa). Of course, in other optional implementations, the test pile foundation can also include other resistance parameters, which are not described here.

[0031] In an embodiment, the plurality of test pile foundations can be uniformly placed in the plurality of experimental areas to accurately measure the actual bearing capacity characteristic value of the test pile foundation.

[0032] Step S14, compare the calculated single pile bearing capacity characteristic value with the actual bearing capacity characteristic value of the test pile foundation in the plurality of experimental areas, combine the static sounding test in the construction site, and inversely optimize and adjust the pile side friction resistance and the end resistance to correct the stratum pile foundation parameters corresponding to each borehole;

[0033] The static sounding test refers to a test process of pressing the test pile foundation into the soil layer of the construction site by using a pressure device and static sounding. By measuring the penetration resistance of the system, some basic physical and mechanical properties of the soil can be determined, such as the deformation modulus of the soil and the allowable bearing capacity of the soil. There are three types of static sounding pressure: mechanical, hydraulic and manual. The static sounding test is carried out on site, the specific penetration resistance (Ps) obtained by the static sounding test is regressed with the relevant indexes of the load test and the soil test, thereby obtaining an empirical formula applicable to some regions or some soil, and the natural foundation bearing capacity of the soil layer of the construction site is determined by the calculation index obtained by the static sounding test.

[0034] In an optional implementation, the pile foundation bearing capacity of each test pile foundation can be parameter inversed on the premise of static sounding data, survey data, etc., combined with existing technical specifications to correct the stratum pile foundation parameters corresponding to each borehole, and then the pile foundation bearing capacity characteristic value of the borehole can be calculated under the stratum pile foundation parameters, so as to select precast piles with different lengths according to the calculated pile foundation bearing capacity characteristic value of the borehole.

[0035] Step S15, calculate the pile foundation bearing capacity characteristic value of the borehole according to the adjusted stratum pile foundation parameters, and draw a pile foundation bearing capacity contour map of each borehole, which is used to represent precast piles with different lengths in different regions, wherein the pile foundation bearing capacity contour map at least identifies a safe area and a non-safe area, in the safe area, the pile foundation length of the precast pile indicated by the pile foundation bearing capacity contour map is determined as the precast pile length in construction; in the non-safe area, the pile foundation length of the precast pile indicated by the pile foundation bearing capacity contour map is increased to a preset length, and the precast pile with the preset length is determined as the precast pile length in construction.

[0036] In addition, it should be noted that the pile foundation bearing capacity contour map can also be marked with three different pile length bearing capacities, which are high bearing capacity, standard bearing capacity and low bearing capacity, wherein the high bearing capacity and the standard bearing capacity correspond to the safe area, and the low bearing capacity corresponds to the non-safe area. In actual construction, the length of the pile foundation of the prefabricated pile based on the low bearing capacity needs to be extended to the preset length, so that the prefabricated pile of the preset length is determined as the pile length in the construction.

[0037] Further, the pile foundation bearing capacity contour map is as shown in Figure 2 The building site is provided with 29 experimental areas, which are A1-A8 and B1-B21, and the pile foundation bearing capacity is marked in the pile foundation bearing capacity contour map by different color regions, so that the staff can reasonably arrange the prefabricated pile in the Yellow River Delta according to the pile foundation bearing capacity contour map. Correspondingly, the actual measured icon of the B20 area is illustrated. As shown in Table 1, there are 1, 2, 3, 4, 10, 11, 12, 13, etc. eight drill hole numbers in the B20 area, wherein the surveying depth corresponding to the drill hole 1 is 35m, the surveying depth corresponding to the drill hole 2 is 25m, the surveying depth corresponding to the drill hole 3 is 30m, the surveying depth corresponding to the drill hole 4 is 25m, the surveying depth corresponding to the drill hole 10 is 25m, the surveying depth corresponding to the drill hole 11 is 35m, the surveying depth corresponding to the drill hole 12 is 25m, and the surveying depth corresponding to the drill hole 13 is 30m. Based on the above, the pile foundation bearing capacity in the B20 area is marked by the color bar on the right side of Figure 2 .

[0038] Further, the pile foundation bearing capacity collected by the above different drill hole numbers is shown in the form of Table 1. By detecting the soil layers of different drill hole numbers, the bearing capacity of the prefabricated pile is marked in the generated pile foundation bearing capacity contour map. The bearing capacity of the prefabricated pile corresponding to the pile foundation bearing capacity contour map can be calculated by the standard value of the pile side friction resistance and the standard value of the end resistance, and the schematic diagram of the standard value of the pile side friction resistance and the standard value of the end resistance is shown in Table 1.

[0039] Table 1

[0040]

[0041] As shown in Table 1, the drill hole number 3 is illustrated. The soil layer corresponding to the drill hole number 3 is silt, and the standard value of the pile side friction resistance (q sik ) of the prefabricated pile after inversion is 30Kpa and the standard value of the end resistance (q pk ) is 1500Kpa. The standard value of the pile side friction resistance and the standard value of the end resistance are converted into the bearing capacity of the prefabricated pile, and the corresponding color is used for marking in the pile foundation bearing capacity contour map.

[0042] It should be noted that, Figure 2 The unit of the pile foundation bearing capacity of the precast pile in the table is KN, and different chroma corresponds to different bearing capacity values.

[0043] Based on the above, in the embodiments of the present application, the actual bearing capacity characteristic value of the test pile foundation in the experimental area is measured, and the single pile bearing capacity characteristic value of the corresponding pile length of a plurality of drill holes is calculated by associating the stratum correlation parameters of the drill holes, the two are compared and analyzed, and the stratum pile foundation parameters corresponding to each drill hole are corrected in combination with the static sounding test, so as to generate pile foundations of different lengths according to the stratum pile foundation parameters, avoid the way of designing pile foundations according to only a unified maximum pile length in the same area, save the production cost of the pile foundation, and improve the accuracy of the precast pile; further, in the present application, the pile foundation bearing capacity contour map is also used to represent the pile length of the precast pile in different areas, and the pile length of the precast pile required in construction can be obtained by the staff according to the pile foundation bearing capacity contour map, which reduces the threshold for the staff to obtain the precast pile and greatly optimizes the process of obtaining the pile length of the precast pile. It can be seen that the pile foundation bearing capacity contour map in the present application can provide valuable reference for technical personnel.

[0044] The above describes a plurality of embodiment schemes provided by the embodiments of the present application, and each optional mode introduced by each embodiment scheme can be combined, cross-referenced in the case of no conflict, thereby extending a plurality of possible embodiment schemes, which can be considered as the embodiment schemes disclosed and disclosed by the embodiments of the present application.

[0045] Although the embodiments of the present application are disclosed as above, the present application is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, therefore the protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. A method for optimizing the length of a precast pile in the construction of a pile foundation in a floodplain, characterized in that, The method comprises the following steps: obtaining stratum-related parameters corresponding to a construction site in a yellow floodplain, wherein the stratum-related parameters include at least one of mechanical parameters of each soil layer in the construction site, pile side friction and end resistance of a precast pile, and the mechanical parameters at least include soil layer thickness and stratum bearing capacity; dividing the construction site into multiple experimental areas, performing pile testing in the multiple experimental areas, and obtaining actual bearing capacity characteristic values of the pile foundations of the test piles through static load testing, wherein the pile foundations of the test piles are prepared based on the stratum-related parameters; calculating single-pile bearing capacity characteristic values of the pile lengths of multiple boreholes corresponding to the boreholes according to actual stratum-related parameters of the boreholes, wherein the number of the boreholes is multiple; comparing the calculated single-pile bearing capacity characteristic values with the actual bearing capacity characteristic values of the pile foundations of the test piles in the multiple experimental areas, and inversely optimizing and adjusting the pile side friction and the end resistance in combination with static sounding tests in the construction site to correct stratum pile foundation parameters corresponding to each borehole; calculating pile foundation bearing capacity characteristic values of the boreholes according to the adjusted stratum pile foundation parameters, and drawing a pile foundation bearing capacity contour map of each borehole, wherein the pile foundation bearing capacity contour map is used to represent precast piles with different pile lengths in different regions, and at least a safe area and a non-safe area are marked in the pile foundation bearing capacity contour map, in the safe area, a pile foundation length of a pre-set pile indicated by the pile foundation bearing capacity contour map is determined as a precast pile length in construction, and in the non-safe area, the pile foundation length of the precast pile indicated by the pile foundation bearing capacity contour map is increased to a pre-set length, and the precast pile with the pre-set length is determined as the precast pile length in construction.

2. The method according to claim 1, wherein the method is characterized by, The step of preparing the pile foundations of the test piles based on the stratum-related parameters comprises the following steps: determining size information of the pile foundations according to the stratum-related parameters, wherein the size information includes at least one of pile foundation length, pile inclination, plane twist angle, inner and outer diameter size, and pile top space coordinates; generating the pile foundations of the test piles based on the size information of the pile foundations.

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