A soil frost heaving force measuring device

Abstract

The application relates to the technical field of soil mechanics characteristic measuring equipment, in particular to a soil frost heaving force measuring device which comprises a piezoelectric ceramic probe, a lower base and an upper base; wherein the lower base is an annular base, the lower base is fixedly connected with the upper base through a suspension, the lower base is provided with a plurality of horizontal probe mounting holes, a horizontal pressure measuring probe is mounted in the horizontal probe mounting hole and the convex film end thereof faces the outside; a vertical probe pedestal is arranged on the upper surface of the lower base, a vertical pressure measuring probe is mounted on the lower base through the vertical probe pedestal and the convex film end thereof faces upwards; the upper base is cylindrical, the vertical pressure measuring probe is mounted in the upper base and the convex film end thereof faces downwards; the upper and lower base structures are used to prevent the measuring device from moving under pressure during the soil layering freezing and thawing process, and the vertical force measuring surface is located on the same horizontal plane, so that the measuring device will not be out of alignment due to the time difference of the layering freezing and thawing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soil mechanics characteristic measuring equipment, in particular to a soil frost heaving force measuring device. BACKGROUND

[0002] Soil belongs to a complex solid, liquid and gas three-phase material. During the freezing and thawing process of soil, the stress and deformation of soil solid particles are mainly controlled by the process of soil water freezing and thawing, and are closely related to the physical properties of soil.

[0003] At present, the mechanical characteristics of soil freezing and thawing process are usually measured by collecting soil samples in the laboratory and burying measuring instruments on site. Although the laboratory measurement has high accuracy, it is limited by the scale of the laboratory site and the size of the equipment. The soil environment beyond the equipment size cannot be measured, and the simulation process can only make the initial pressure and water content of the measurement approximate to the actual environment, but it is difficult to reproduce the gas content at different depths in the actual environment, resulting in errors that cannot be corrected and limitations. In the scheme of burying measuring instruments on site, since the soil freezing and thawing occurs gradually from top to bottom, the gradient rate is related to the temperature change rate. When the temperature changes rapidly, the freezing and thawing process of the soil will appear the process characteristics of approximate stratification, and the related measuring probes buried in the process are stratified, and the soil has elasticity, which easily leads to the movement of the measuring probes in the process of freezing and thawing, and further leads to a large decline in the accuracy of the measured data and the direction accuracy. SUMMARY

[0004] Therefore, it is necessary to provide a soil frost heaving force measuring device, which adopts an on-site buried measurement method to solve the above problems.

[0005] A soil frost heaving force measuring device, comprising a piezoelectric ceramic probe, a lower base, and an upper base; wherein the piezoelectric ceramic probe is a cylindrical pressure probe wrapped in a stainless steel shell, one end of the stainless steel shell is a convex film for force transmission with the probe, and the other end of the stainless steel shell is a threaded plug with a wire port; the piezoelectric ceramic probe has multiple probes, which are divided into horizontal pressure measuring probes and vertical pressure measuring probes; the lower base is an annular base, and the lower base is fixedly connected to the upper base through a suspension; the lower base is provided with multiple horizontal probe mounting holes, the horizontal pressure measuring probes are mounted in the horizontal probe mounting holes, and the convex film end of the horizontal pressure measuring probes faces outward; a vertical probe pedestal is arranged on the upper surface of the lower base, and the vertical pressure measuring probes are mounted on the lower base through the vertical probe pedestal, and the convex film end of the vertical pressure measuring probes faces upward; the upper base is a cylinder, and the vertical pressure measuring probes are mounted in the upper base, and the convex film end of the vertical pressure measuring probes faces downward; the convex film end of the hammer pressure measuring probe mounted on the lower base and the vertical pressure measuring probe mounted in the upper base is located on the same horizontal plane.

[0006] When burying, first connect the lines of each piezoelectric ceramic probe and perform equipment zeroing, position horizontally based on the annular surface of the lower base, then perform positioning and filling, and vibrate the filling during the filling process to make it uniform until the filling is completed, to complete the burying operation.

[0007] When the layered freezing process occurs, the upper base first contacts the frozen soil layer, and the freezing pressure borne by the upper base is downward, which is supported by the lower surface of the lower base and the suspension to prevent it from moving. When the lower base contacts the frozen soil layer, the upper base and the soil layer around the suspension have completed the freezing process, thereby preventing the lower base from moving. When the layered thawing process occurs, the upper base, the suspension and the lower base also share the force to support, thereby preventing the device from moving.

[0008] When measuring the pressure of the layered freezing and thawing process, since the pressure measuring surfaces of the vertical pressure measuring probes are located on the same horizontal plane, the pressure measuring surfaces do not have depth and time difference for the measurement of the pressure of the layered freezing and thawing process, so that the related pressure change parameters and pressure direction difference can be accurately measured, and the time difference caused by freezing and thawing in the layered freezing and thawing process caused by rapid temperature change is not lost.

[0009] Preferably, the horizontal pressure measuring probe has four, which are uniformly distributed on the annular surface of the lower base, and the average value thereof is used when measuring the horizontal pressure to prevent the measurement from being inaccurate due to the failure of the filling vibration uniformity operation; the vertical pressure measuring probe has three, two of which are uniformly installed on the lower base, and one is installed in the upper base; the quality distribution of the measuring device is uniform and symmetrical under the structure, and the adverse effect of its self-weight on the measurement result is minimal.

[0010] Preferably, the design further comprises an anchor plate and an anchor plate frame, the anchor plate is a horizontally arranged stainless steel plate, which is connected and fixed with the lower base through the anchor plate frame, and the anchor plate is buried below the lower base. In the environment with high soil moisture content and large elasticity, such as irrigation areas, riverbanks, riverbeds in dry seasons, etc., additional support is provided by the anchor plate to prevent it from moving during the freezing and thawing process.

[0011] Further, the anchor plate is provided with tines composed of vertical metal sheets, which increase the contact area between the anchor plate and the soil, making the positioning and support more stable. Further, the tines below the anchor plate are triangular, and the tines above the anchor plate are grid-shaped. The triangular tines can be easily inserted into the soil below and avoid air being trapped between the anchor plate and the soil during burying, and the grid above the anchor plate increases the contact area with the soil, making the anchor plate more stable.

[0012] Further, the anchor plate is provided with a marker rod, which extends upward from the anchor plate to protrude above the ground. The marker rod serves as a protection device for the sensor wiring, preventing damage to the wiring at a large burial depth and causing the measuring device to fail. At the same time, the marker rod also serves as a ground marker during burying, preventing the device from being lost.

[0013] The application provides a soil frost heaving force measuring device, which is not pressed and moved in the soil layering freezing and thawing process through the upper and lower base structure, and the vertical force measuring surface is located on the same horizontal plane, so that the measuring error caused by the time difference of the layering freezing and thawing is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a specific embodiment principle structure diagram of the soil frost heaving force measuring device.

[0015] Figure 2 It is a top view structure diagram of the specific embodiment of the soil frost heaving force measuring device.

[0016] Figure 3 It is a top view structure diagram of the upper base and the lower base of the specific embodiment of the soil frost heaving force measuring device.

[0017] Figure 4 It is a bottom view structure diagram of the upper base and the lower base of the specific embodiment of the soil frost heaving force measuring device.

[0018] Figure 5 It is a piezoelectric ceramic probe structure diagram of the specific embodiment of the soil frost heaving force measuring device.

[0019] In the figure: piezoelectric ceramic probe 1, probe 101, stainless steel shell 102, convex film 103, threaded plug 104, wire port 105, lower base 2, horizontal probe mounting hole 201, vertical probe pedestal 202, suspension 203, upper base 3, anchor plate 4, anchor plate rack 401, harrow tooth 402, marker rod 403, screw 5. DETAILED DESCRIPTION

[0020] The application relates to a soil frost heaving force measuring device which comprises a piezoelectric ceramic probe 1, a lower base 2 and an upper base 3; wherein the piezoelectric ceramic probe 1 is a cylindrical pressure probe wrapped in a stainless steel shell 102, one end of the stainless steel shell 102 is a convex film 103 which is in contact with the probe 101 to transmit force, and the other end of the stainless steel shell 102 is a threaded plug 104 which is provided with a wire port 105; the piezoelectric ceramic probe 1 is multiple and is divided into horizontal pressure measuring probes and vertical pressure measuring probes; the lower base 2 is an annular base which is fixedly connected with the upper base 3 through a suspension 203; the lower base 2 is provided with multiple horizontal probe mounting holes 201, the horizontal pressure measuring probes are mounted in the horizontal probe mounting holes 201 and the convex film 103 ends thereof are directed to the outside; a vertical probe pedestal 202 is arranged on the upper surface of the lower base 2, the vertical pressure measuring probes are mounted on the lower base 2 through the vertical probe pedestal 202 and the convex film 103 ends thereof are directed to the upper side; the upper base 3 is cylindrical, the vertical pressure measuring probes are mounted in the upper base 3 and the convex film 103 ends thereof are directed to the lower side; the convex film 103 ends of the hammer pressure measuring probes mounted on the lower base 2 and the vertical pressure measuring probes mounted in the upper base 3 are located on the same horizontal plane.

[0021] The horizontal pressure measuring probes are four and are uniformly distributed on the ring surface of the lower base 2, the average value of the horizontal pressure measuring probes is adopted when the horizontal pressure is measured, and the inaccuracy of measurement caused by the uneven filling and vibration is prevented; the vertical pressure measuring probes are three, two of which are uniformly mounted on the lower base 2 and one of which is mounted in the upper base 3; the quality distribution of the measuring device is uniform and symmetrical, and the self-weight of the measuring device has the least adverse effect on the measurement result.

[0022] The measuring device further comprises an anchor plate 4 and an anchor plate frame 401, the anchor plate 4 is a horizontally arranged stainless steel plate which is fixedly connected with the lower base 2 through the anchor plate frame 401, and the anchor plate 4 is buried below the lower base 2; in the environment with high soil moisture content and large elasticity, such as irrigation areas, river beaches and riverbeds in the dry season, the anchor plate 4 provides additional support to prevent the anchor plate 4 from moving in the freezing and thawing process.

[0023] The anchor plate 4 is provided with rake teeth 402 which are composed of vertical metal sheets, the rake teeth 402 increase the contact area between the anchor plate 4 and the soil, and the positioning and support of the anchor plate 4 are more stable; the rake teeth 402 below the anchor plate 4 are triangular, the rake teeth 402 above the anchor plate 4 are grid-shaped, the triangular rake teeth 402 can be conveniently stuck into the soil below and avoid air being trapped between the anchor plate 4 and the soil, and the grid above the anchor plate 4 increases the contact area with the soil, so that the anchor plate 4 is more stable in the buried state.

[0024] The anchor plate 4 is provided with a marker rod 403 which extends upward from the anchor plate 4 to the ground surface, the marker rod 403 serves as a protection device for the sensor wire and prevents the wire from being damaged to cause the measuring device to fail when the buried depth is large, and the marker rod 403 also serves as a ground mark in the buried state and prevents the equipment from being lost.

[0025] When buried, first connect the line of each piezoelectric ceramic probe 1 and perform equipment zeroing, bury the anchor plate 4 and the anchor plate frame 401, connect the anchor plate frame 401 and the lower base 2 through the screw 5, and perform horizontal positioning and leveling based on the annular surface of the lower base 2, then fill the soil, and fill the soil between the lower base 2 and the upper base 3 through the hole in the center of the annular surface of the lower base 2 during the filling process, and perform vibration homogenization on the filled soil until the filling process is completed, to complete the burying operation.

[0026] When the layered freezing process occurs, the upper base 3 first contacts the frozen soil layer, and the freezing pressure borne by it is downward, which is shared and supported by the anchor plate 4, the lower surface of the lower base 2 and the suspension 203 to prevent it from moving, and when the lower base 2 contacts the frozen soil layer, the upper base 3 and the soil layer around the suspension 203 have completed the freezing process, and cooperate with the support of the anchor plate 4, thereby preventing the lower base 2 from moving. When the layered thawing process occurs, the upper base 3, the suspension 203 and the lower base 2 also share and support the force, thereby preventing the equipment from moving.

[0027] When measuring the pressure of the layered freezing and thawing process, since the pressure measuring surface of the vertical pressure measuring probe is located in the same horizontal plane, it has no depth and time difference in the measurement of the pressure of the layered freezing and thawing process, so it can accurately measure the relevant pressure change parameters and pressure direction difference, and will not be inaccurate due to the time difference of freezing and thawing caused by the rapid change of temperature in the layered freezing and thawing process.

Claims

1. A soil frost heave force measuring device, characterized by, The piezoelectric ceramic probe, the lower base, and the upper base are included. The piezoelectric ceramic probe is a cylindrical pressure probe wrapped in a stainless steel shell, one end of the stainless steel shell is a convex film, and the other end is a threaded plug, and a wire port is arranged on the threaded plug; the piezoelectric ceramic probe has multiple horizontal pressure measuring probes and vertical pressure measuring probes; The lower base is an annular base, and the lower base is fixedly connected to the upper base through a suspension; the lower base is provided with multiple horizontal probe mounting holes, the horizontal pressure measuring probes are mounted in the horizontal probe mounting holes, and the convex film end of the horizontal pressure measuring probes faces the outer side; a vertical probe pedestal is arranged on the upper surface of the lower base, the vertical pressure measuring probes are mounted on the lower base through the vertical probe pedestal, and the convex film end of the vertical pressure measuring probes faces upward; the upper base is a cylinder, the vertical pressure measuring probes are mounted in the upper base, and the convex film end of the vertical pressure measuring probes faces downward; the convex film end of the vertical pressure measuring probes mounted on the lower base and the vertical pressure measuring probes mounted in the upper base are located on the same horizontal plane.

2. A soil frost heaving force measuring device as claimed in claim 1, wherein, The horizontal pressure measuring probes are four, and are uniformly distributed on the annular surface of the lower base; the vertical pressure measuring probes are three, two of which are uniformly mounted on the lower base, and one is mounted in the upper base.

3. The soil frost heaving force measuring device according to claim 1, wherein The anchor plate and the anchor plate frame are further included, the anchor plate is a horizontally arranged stainless steel plate, and the anchor plate is fixedly connected to the lower base through the anchor plate frame and is buried below the lower base.

4. A soil frost heaving force measuring device as claimed in claim 3, wherein Rake teeth composed of vertical metal sheets are arranged on the anchor plate.

5. The soil frost heaving force measuring device of claim 3, wherein, A marker rod is arranged on the anchor plate, the marker rod extends upward from the anchor plate to the ground surface.

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