CN-121992829-A - Device for monitoring horizontal soil pressure change of existing pile foundation and frictional resistance calculation method

Abstract

The invention discloses a device for monitoring the horizontal soil pressure change of an existing pile foundation and a friction resistance calculation method, which comprise a machine body, wherein the machine body comprises a conical tip and a hollow tube which are positioned at the bottom, the hollow tube is provided with a plurality of mounting holes, each mounting hole is provided with an annular bulge which extends outwards, one end of each sensor is connected with each annular bulge, the other end of each sensor is arranged in an inner cavity of the hollow tube, the tail of each sensor is connected with an elastic abutting device, a signal processing module and a pressure control module are arranged at the top end of the hollow tube, the pressure control module is arranged at one end, far away from the conical tip, of the hollow tube, the pressure control module is used for measuring the horizontal soil pressure change of the existing pile foundation, and an expandable sleeve is connected with the outer wall of the machine body in a ring sleeve mode. Accurately measuring pile foundation stress change, calculating pile side friction resistance by adopting an accurate integrating method and considering the nonlinear characteristic of soil mass, integrating layer by layer, and obtaining the friction resistance distribution and total side friction resistance of the pile foundation at different depths.

Inventors

• ZHAO CHENXU
• YANG JING
• BAI JINZHOU
• CUI ZHEN
• MA JINLONG
• HOU JIANLIN
• CHEN XINJIE
• YUE BIN
• MA WENJING
• ZHANG ZHUANGZHUANG
• LI HONGSHENG
• CHEN QIANGQIANG
• QIU SONG
• JIN GUOQIANG

Assignees

• 中铁北京工程局集团有限公司
• 深圳地铁建设集团有限公司
• 中铁南方投资集团有限公司

Dates

Publication Date

20260508

Application Date

20260203

Claims (10)

1. 1. To current pile foundation level soil pressure change monitoring devices, its characterized in that includes: the device comprises a machine body, a main body and a plurality of guide rails, wherein the machine body comprises a conical tip at the bottom and an external hollow tube (4) connected with the conical tip, the hollow tube (4) is provided with a plurality of mounting holes, and each mounting hole is provided with an annular protrusion extending outwards; The sensor (3), one end of the sensor (3) is connected with the annular bulge, the other end of the sensor is arranged in the inner cavity of the hollow tube (4), and the tail part of the sensor (3) is connected with an elastic abutting device (33); the signal processing module is arranged at one end of the hollow tube far away from the conical tip; the pressure control module is arranged at one end of the hollow pipe (4) far away from the conical tip and is used for measuring the horizontal soil pressure change of the existing pile foundation; An expandable sleeve (6), the expandable sleeve (6) is connected with the outer wall of the machine body in a loop mode, and the expandable sleeve (6) is driven to expand or be stored through pressure media.
2. 2. The apparatus for monitoring the horizontal soil pressure change of an existing pile foundation according to claim 1, wherein the hollow tube is a cylindrical tube.
3. 3. The device for monitoring the horizontal soil pressure change of the existing pile foundation according to claim 1, comprising a data transmission line (1) for connecting the signal processing module with an upper computer.
4. 4. The device for monitoring the horizontal soil pressure change of the existing pile foundation according to claim 1, wherein the outer wall of the expandable casing (6) is provided with thread patterns.
5. 5. The device for monitoring the horizontal soil pressure change of the existing pile foundation according to claim 1, wherein the sensor comprises a supporting tube (34) and a piezoelectric material (35) arranged in the supporting tube (34), one end of the supporting tube (34) is connected with the elastic abutting device (33), and the end is provided with a pressure control system (32) and a data transmission wire (31).
6. 6. The device for monitoring the change of the horizontal soil pressure of the existing pile foundation according to claim 1, wherein the elastic abutting device (33) is a spring.
7. 7. The device for monitoring the change of the horizontal soil pressure of the existing pile foundation according to claim 1, wherein the conical tip is a drill bit device (5).
8. 8. A method for calculating frictional resistance to an existing pile foundation, which is applied to the device for monitoring the change of the horizontal soil pressure of the existing pile foundation according to any one of claims 1 to 7, and comprises the following steps: S1, calibrating the sensor according to environmental parameter conditions; S2, placing a horizontal soil pressure change monitoring device of the existing pile foundation close to the pile side wall of the existing pile foundation (8), placing at least three monitoring devices (7) close to the side of the newly-built tunnel in the horizontal direction, and placing at least one monitoring device (7) away from the side of the tunnel to form a group of monitoring groups, wherein the number of the monitoring groups is set to be that a plurality of groups are distributed along the length direction of the existing pile foundation (8); s3, controlling the expandable sleeve to expand and press the expandable sleeve to the soil body, and zeroing the initial stress value of the sensor; S4, converting the stress data acquired by the sensor at different depths in the soil into a continuous stress function by adopting a multipoint interpolation method, taking the stress data into nonlinear stress-strain relation data under different loading conditions of nonlinear characteristic reaction of the soil, accurately calculating friction force at each depth layer by layer and in a dividing way according to different soil depths, and accumulating the friction force or calculating the friction force under the condition of not considering time change.
9. 9. The method for calculating the frictional resistance to the existing pile foundation according to claim 8, wherein the environmental parameter conditions include known stress conditions and soil conditions.
10. 10. The method for calculating the frictional resistance to the existing pile foundation according to claim 8, wherein the frictional resistance calculation specifically comprises: high precision measurement of stress variation by sensors at different depths The measured stress data generate a high-precision stress distribution curve; high order interpolation, which is to convert discrete stress data points into continuous stress functions by using a multi-point interpolation method ; The nonlinear soil model adopts a nonlinear stress-strain model to describe the real behavior of the soil, and the main parameters are the friction angle and the shear modulus of the soil so as to reflect the nonlinear stress-strain relation of the soil under different loading conditions; integration method based on stress function And the nonlinear characteristic of the soil mass, calculating pile side friction resistance through the following integral formula: pile side friction resistance formula correction: Layer by layer integration is carried out on different depths of a pile foundation (8), the friction resistance at each depth is accurately calculated by combining the characteristics of soil bodies of each layer, and the friction resistances are accumulated to obtain the total side friction resistance of the pile body; Wherein z is depth in meters; is the stress at the depth z, the unit is pascal, the friction angle is the friction angle between the soil body and the pile foundation (8), the unit of the friction characteristic of the soil body on the sliding surface is degree, and the shear modulus Is the shear modulus of the soil body, and represents the resistance of the soil body to shear deformation, wherein the unit is pascal; Is the total friction force at the pile side, and the unit is Newton; pile side friction at depth z in pascals; Is the circumference of the pile foundation (8) at depth z in meters; And The pile is characterized in that the pile has a start depth and an end depth, wherein the units are meters, sigma (z) is soil stress at the depth z, the units are pascals, phi (z) is soil friction angle at the depth z, and the units are degrees; Is the differential of the pile contact area at depth z in square meters, the circumference of pile foundation (8) Multiplied by depth differentiation I.e. 。

Description

Device for monitoring horizontal soil pressure change of existing pile foundation and frictional resistance calculation method Technical Field The application relates to the technical field of stress measurement, in particular to a device for monitoring the pressure change of horizontal soil of an existing pile foundation and a friction resistance calculation method. Background When a tunnel is newly built beside an existing pile foundation, especially in a city or an area with higher groundwater level, soil displacement, stress redistribution and groundwater change can be caused. These factors can affect the frictional resistance of existing pile foundations and thus their load carrying capacity. Therefore, the monitoring of the change condition of the frictional resistance of the existing pile foundation is important in the construction process of the newly-built tunnel. The change of pile foundation friction resistance can reflect the interaction between the pile foundation and the surrounding soil body and the stability of the soil body. By monitoring the pile foundation friction resistance of the existing pile, the state of the pile foundation can be monitored in the tunnel construction process, the influence of construction on the pile foundation is evaluated, potential problems such as soil settlement, low pile foundation bearing capacity and the like are found in time, a reasonable construction plan and an emergency plan are formulated, and the safety in the construction process is guaranteed. At present, the existing pile foundation horizontal soil pressure change device is installed on the pile foundation when the pile foundation is mostly constructed, the direction of the stress change monitored by the traditional monitoring device is single, the existing pile foundation horizontal soil pressure change device cannot be in good contact with soil, and the accuracy and stability of data acquisition cannot be guaranteed. Disclosure of Invention The invention mainly aims at the problems, provides a device for monitoring the horizontal soil pressure change of the existing pile foundation and a friction resistance calculation method, and aims to monitor the horizontal soil pressure of the existing pile foundation when a tunnel is constructed beside an operated construction structure, monitor the change conditions of the horizontal soil pressure of the existing pile foundation in different directions better and improve the accuracy of acquired data. In order to achieve the above object, the present invention provides a device for monitoring the change of the horizontal soil pressure of the existing pile foundation, comprising: The device comprises a machine body, a plurality of mounting holes, a plurality of guide rails and a plurality of guide rails, wherein the machine body comprises a conical tip at the bottom and an external hollow tube connected with the conical tip; the sensor is connected with the annular bulge at one end and is arranged in the cavity of the hollow tube at the other end, and the tail part of the sensor is connected with an elastic abutting device; the signal processing module is arranged at one end of the hollow tube far away from the conical tip; the pressure control module is arranged at one end of the hollow pipe far away from the conical tip and is used for measuring the pressure change of the horizontal soil of the existing pile foundation; And the expandable sleeve is connected with the outer wall of the machine body in a sleeved mode, and the expandable sleeve is driven to expand or be stored through pressure media. Further, the hollow tube is a cylindrical tube. Further, the system comprises a data transmission line for connecting the signal processing module and the upper computer. Further, the outer wall of the expandable casing is provided with thread patterns. Further, the sensor comprises a support tube and a piezoelectric material arranged in the support tube, one end of the support tube is connected with the elastic abutting device, and the end of the support tube is provided with a pressure control system and a lead for data transmission. Further, the elastic abutment device is a spring. Further, the tapered tip is a drill bit device. The invention also provides a method for calculating the frictional resistance of the existing pile foundation, which is applied to the device for monitoring the horizontal soil pressure change of the existing pile foundation, and comprises the following steps: S1, calibrating the sensor according to environmental parameter conditions; S2, placing a horizontal soil pressure change monitoring device of the existing pile foundation close to the pile side wall of the existing pile foundation, placing at least three monitoring devices close to the side of the newly-built tunnel in the horizontal direction, and placing at least one monitoring device far away from the tunnel to form a group of monitoring groups; s3, controlling the expandab