A method and apparatus for selecting materials for a complete casing

Abstract

This invention discloses a method and apparatus for selecting casing materials. The method includes: S1, acquiring soil layer information of the pile foundation area and determining the torque distribution of the soil layers based on the soil layer information; S2, obtaining the relationship between the pile foundation depth and the torque acting on the casing cross-section based on the torque distribution of the soil layers, and converting it into a relationship between the pile foundation depth and the shear stress acting on the casing; S3, matching the strength of the casing material with the relationship between the pile foundation depth and the shear stress acting on the casing, thereby selecting different casing materials according to the pile foundation depth. This invention can achieve the selection of materials with different strengths for different casing stresses, avoiding the uneconomical phenomena in traditional casing material selection, saving resources and costs, and allowing for the selection of more suitable full-rotation drilling rigs, avoiding waste caused by using excessively powerful full-rotation drilling rigs.

Description

Technical Field

[0001] This invention relates to the field of preferred materials for pile foundation casings, and particularly to a method and apparatus for selecting casing materials. Background Technology

[0002] The construction of new urban roads and bridges, and the establishment of urban expressway networks, not only effectively alleviate traffic congestion but also enhance the aesthetics of the city. New bridges in urban areas have become an indispensable part of urban transportation infrastructure. Furthermore, during urban bridge construction, new bridges inevitably intersect with subways and tunnels. Since subways and tunnels have high requirements for the deformation of the surrounding soil, traditional pile foundation construction methods, such as bored piles, which cause significant ground disturbance and noise, are no longer sufficient. Therefore, full-casing, full-rotation drilling rigs are often used in such conditions.

[0003] Currently, there is limited research on full-circuit drilling rig casings. Traditionally, the selection of casing materials for full-circuit drilling rigs is determined by calculating the sum of cumulative shear stresses along the entire length of the pile foundation. Furthermore, the same strength steel is used for the casing along the entire pile length, without considering the stress characteristics of the casing, resulting in a waste of resources and significant economic losses. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention divides the shear stress distribution range of the cross section into different segments based on the relationship curve between the casing depth and the cross section shear stress. The casing within the shear stress range of different segments is made of steel with corresponding strength, thus achieving the purpose of selecting the appropriate steel for the casing under stress conditions.

[0005] To achieve the above objectives, the present invention provides a method for selecting a complete casing material, comprising the following steps.

[0006] S1. Obtain soil layer information in the pile foundation area, and determine the torque distribution of the soil layer based on the soil layer information;

[0007] S2. Obtain the relationship between the pile foundation depth and the torque acting on the casing section based on the torque distribution of the soil layer, and convert it into the relationship between the pile foundation depth and the shear stress acting on the casing.

[0008] S3. Match the relationship between the pile foundation depth and the shear stress acting on the casing with the strength of the casing material, and select different casing materials according to the pile foundation depth.

[0009] Furthermore, S1 specifically includes,

[0010] The distribution of soil layers within the pile foundation area is determined based on the depth of the pile foundation.

[0011] Determine the ultimate skin friction value of the soil layer based on the soil layer distribution;

[0012] The torque distribution of the soil layer is determined based on the ultimate skin friction value and the thickness of the soil layer.

[0013] Furthermore, S2 specifically includes,

[0014] With the cumulative torque value at the pile tip being 0, the cumulative torque value of each soil layer is obtained along the direction from the pile tip to the pile tail, and the cumulative torque value of each soil layer is connected to obtain the relationship between the pile foundation depth and the torque acting on the casing section.

[0015] The torque acting on the casing section is converted into shear stress acting on the casing, thus obtaining the relationship between the pile depth and the shear stress acting on the casing.

[0016] Furthermore, S3 specifically includes dividing the shear stress of the casing into different segments, each segment corresponding to a casing material of a certain strength, and selecting the casing material according to the segment.

[0017] Furthermore, after selecting different casing materials according to the pile foundation depth, S3 also fixes these casing materials to form an overall casing structure.

[0018] Furthermore, the fixing includes at least one of riveting, threaded connection, and welding.

[0019] The present invention also provides a device for selecting the material of the casing, comprising,

[0020] An information acquisition unit is used to acquire soil layer information in the pile foundation area and determine the torque distribution of the soil layer based on the soil layer information.

[0021] The data conversion unit obtains the relationship between the pile foundation depth and the torque acting on the casing section based on the torque distribution of the soil layer, and converts it into the relationship between the pile foundation depth and the shear stress acting on the casing.

[0022] The material selection unit matches the strength of the casing material with the relationship between the pile foundation depth and the shear stress acting on the casing, thereby selecting different casing materials according to the pile foundation depth.

[0023] Furthermore, the material selection unit is specifically used to divide the shear stress of the casing into different sections, each section corresponding to a casing material of a certain strength, and to select the casing material according to the section.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] This invention converts the torque acting on the casing cross-section into shear stress acting on the casing, thus obtaining the relationship between the pile foundation depth and the shear stress acting on the casing. Subsequently, the shear stress is divided into different sections, each corresponding to a steel of a specific strength, thereby enabling the selection of different casing materials based on the pile foundation depth. This invention allows for the selection of steel of different strengths to address varying casing stresses, avoiding the uneconomical practices of traditional casing material selection, saving resources and costs. Furthermore, it allows for the use of more suitable full-rotation drilling rigs, avoiding the waste caused by using excessively powerful full-rotation drilling rigs. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A flowchart illustrating a method for selecting a full casing material is shown in the embodiment;

[0028] Figure 2 A bar chart showing the torque distribution of different soil layers in the embodiment is shown;

[0029] Figure 3 The diagram showing the relationship between the pile depth and the torque acting on the casing section in the embodiment is illustrated.

[0030] Figure 4 The figure shows the relationship between the pile depth and the shear stress acting on the casing in the embodiment, as well as the curve of the casing material selection;

[0031] Figure 5 A schematic diagram of a full casing material selection device is shown in the embodiment. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] like Figure 1 As shown, one embodiment of the present invention provides a method for selecting a complete casing material, including the following steps:

[0034] S1. Obtain soil layer information in the pile foundation area and determine the torque distribution of the soil layer based on the soil layer information.

[0035] The distribution of soil layers within the pile foundation area is determined based on the depth of the pile foundation.

[0036] Determine the ultimate skin friction value of the soil layer based on the soil layer distribution;

[0037] The torque distribution of the soil layer is determined based on the ultimate skin friction value and the thickness of the soil layer. Figure 2 A bar chart showing the torque distribution of different soil layers is presented. By drawing this chart, the torque situation of each soil layer within the pile foundation range at different depths can be determined, laying the foundation for subsequent steps.

[0038] S2. Obtain the relationship between the pile foundation depth and the torque acting on the casing section based on the torque distribution of the soil layer, and convert it into the relationship between the pile foundation depth and the shear stress acting on the casing.

[0039] Assuming the cumulative torque at the pile tip is 0, the cumulative torque value for each soil layer is obtained along the direction from the pile tip to the pile tail. The pile tip, also called the pile cap or pile bottom, is the lowest point of the pile, and the pile tail is the end of the pile tip closest to the ground. The cumulative torque values ​​for each soil layer are then connected to obtain the relationship between the pile depth and the torque acting on the casing section. The results are as follows: Figure 3 As shown;

[0040] By calculating the torsional section modulus of the casing, the torque acting on the casing section is converted into shear stress acting on the casing, thus obtaining the relationship between the pile depth and the shear stress acting on the casing.

[0041] S3. Match the relationship between the pile foundation depth and the shear stress acting on the casing with the strength of the casing material, and select different casing materials according to the pile foundation depth.

[0042] The relationship between pile depth and shear stress acting on the casing was plotted as a curve, and the casing material was matched according to the shear stress of the casing. The results are as follows: Figure 4 As shown, it can be seen that the shear stress τ acting on the casing has the following range: τ1 < τ2 < τ3 < τ4 < τ5. There are five different types of casing materials with varying strengths, all made of steel. The strength of the steel increases sequentially from Type I, Type II, Type III, Type IV, to Type V. When the shear stress acting on the casing at the pile depth is [0, τ1), Type I steel is selected as the casing material; when the shear stress acting on the casing at the pile depth is [τ1, τ2), Type II steel is selected; when the shear stress acting on the casing at the pile depth is [τ2, τ3), Type III steel is selected; when the shear stress acting on the casing at the pile depth is [τ3, τ4), Type IV steel is selected; and when the shear stress acting on the casing at the pile depth is [τ4, τ5], Type V steel is selected. Figure 4The values ​​d1, d2, d3, d4, and d5 indicate the appropriate locations and lengths for Type I, Type II, Type III, Type IV, and Type V steel, respectively. Based on the pile foundation depth and the stress conditions of the casing, different casing materials can be selected. The shear stress of the casing is divided into different sections, each corresponding to a casing material of a specific strength. Selecting casing materials based on these sections avoids the uneconomical practices of traditional casing material selection, saving resources and costs. Furthermore, based on the selected casing material, a more suitable full-rotation drilling rig can be chosen, avoiding the waste caused by using excessively powerful full-rotation drilling rigs.

[0043] After selecting different casing materials according to the pile foundation depth, these casing materials are fixed to form an integral casing structure for application. Fixing methods can include riveting, threaded connection, welding, etc.

[0044] It should be noted that this embodiment divides the shear stress acting on the casing into 5 intervals, but it is not limited to these. In actual judgment, the specific division needs to be made according to the stratum properties, pile foundation depth, and casing steel strength.

[0045] like Figure 5 As shown, one embodiment of the present invention provides a device for selecting a full casing material, comprising,

[0046] An information acquisition unit is used to acquire soil layer information in the pile foundation area and determine the torque distribution of the soil layer based on the soil layer information.

[0047] The data conversion unit obtains the relationship between the pile foundation depth and the torque acting on the casing section based on the torque distribution of the soil layer, and converts it into the relationship between the pile foundation depth and the shear stress acting on the casing.

[0048] The material selection unit matches the strength of the casing material with the relationship between the pile foundation depth and the shear stress acting on the casing, thereby selecting different casing materials according to the pile foundation depth.

[0049] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for selecting materials for a complete casing, characterized in that, Includes the following steps, S1. Obtain soil layer information in the pile foundation area, and determine the torque distribution of the soil layer based on the soil layer information; S2. Obtain the relationship between the pile foundation depth and the torque acting on the casing section based on the torque distribution of the soil layer, and convert it into the relationship between the pile foundation depth and the shear stress acting on the casing. S3. Match the relationship between the pile foundation depth and the shear stress acting on the casing with the strength of the casing material, so as to select different casing materials according to the pile foundation depth, which can save resources and costs and select a suitable full-rotation drilling rig. S1 specifically includes, The distribution of soil layers within the pile foundation area is determined based on the depth of the pile foundation. Determine the ultimate skin friction value of the soil layer based on the soil layer distribution; The torque distribution of the soil layer is determined based on the ultimate skin friction value and the thickness of the soil layer. S2 specifically includes, With the cumulative torque value at the pile tip being 0, the cumulative torque value of each soil layer is obtained along the direction from the pile tip to the pile tail, and the cumulative torque value of each soil layer is connected to obtain the relationship between the pile foundation depth and the torque acting on the casing section. The torque acting on the casing section is converted into shear stress acting on the casing, thus obtaining the relationship between the pile depth and the shear stress acting on the casing. S3 specifically includes dividing the shear stress of the casing into different sections, with each section corresponding to a casing material of a certain strength, and selecting the casing material according to the section.

2. The method for selecting materials for the entire casing according to claim 1, characterized in that, After selecting different casing materials according to the pile foundation depth, S3 also fixes these casing materials to form an overall casing structure.

3. The method for selecting the material of the entire casing according to claim 2, characterized in that, The fixing includes at least one of riveting, threaded connection, and welding.

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