Device and method for detecting the thickness of a sediment

Abstract

This invention provides a device and method for detecting sediment thickness. The device comprises an outer frame, an electric telescopic rod, a measuring rod, and a vibration measuring pair. In the process of constructing diaphragm walls or bored piles, after trenching or drilling is completed, sediment needs to be removed from the trench or hole through mud circulation. Controlling sediment thickness is a key construction step to ensure the vertical bearing capacity of diaphragm walls or bored piles. Accurate measurement of sediment thickness is significant for adjusting mud circulation cleaning time and mud mixing process. This invention addresses the detection of sediment thickness after trenching or drilling during the construction of diaphragm walls and bored piles. Based on accurate measurement, it controls sediment thickness, improves the construction quality of diaphragm walls or bored piles, and ensures that the vertical bearing capacity meets requirements.

Description

Technical Field

[0001] This invention relates to a device and method for detecting the thickness of sediment. Background Technology

[0002] Currently, the thickness of sediment in diaphragm walls or bored piles is mainly determined by resistivity or penetration resistance testing. This involves measuring changes in soil resistivity or penetration resistance at different depths at the bottom of the trench or borehole to differentiate the sediment from the bearing stratum and thus determine the sediment thickness. However, current methods are mostly single-point measurements, resulting in significant differences in results at different locations. Obtaining a comprehensive understanding of the sediment at the bottom of the trench or borehole requires multiple measurements, which is time-consuming and labor-intensive. Furthermore, the determination of sediment thickness relies on extracting data from locations where the test results change, which may lead to gradual changes in the results or flat curves that make it impossible to determine the sediment thickness. Summary of the Invention

[0003] The purpose of this invention is to provide a device and method for detecting the thickness of sediment.

[0004] To address the above problems, the present invention provides a device for detecting the thickness of sediment, comprising:

[0005] Outer frame;

[0006] The outer frame contains two electrically operated telescopic rods, two measuring rods, and a vibration measurement pair. The vibration measurement pair includes two vibration measuring devices arranged opposite each other. The two electrically operated telescopic rods are arranged at intervals. The electrically operated telescopic rods are connected to the outer frame. The lower part of each electrically operated telescopic rod is connected to a measuring rod. The lower part of each measuring rod is equipped with one vibration measuring device from the vibration measurement pair.

[0007] Furthermore, in the aforementioned device for detecting sediment thickness, each vibration measuring device includes: a vibration generator and a pore water pressure gauge.

[0008] According to another aspect of the present invention, a method for detecting the thickness of sediment is also provided, the method comprising:

[0009] The device for detecting the thickness of sediment described in any of the above items is lowered to the bottom of the tank or the bottom of the hole;

[0010] The measuring rod and the excitation measuring pair are pressed into the sediment and soil by an electric telescopic rod. During the downward movement of the measuring rod and the excitation measuring pair, the center elevation depth of the excitation measuring pair is recorded by the measuring rod, and the wave velocity of the saturated soil at different center elevation depths is recorded by the excitation measuring pair.

[0011] Based on the recorded wave velocities of saturated soil at different center elevation depths, soil parameter variation curves at different depths are plotted, and the location of sediment is determined based on these curves.

[0012] Furthermore, in the method for detecting sediment thickness, wave velocity is measured on saturated soil at different center elevation depths using vibration measurement, including:

[0013] The vibration wave signal propagates from the vibration generator of one excitation measuring device in the excitation measuring pair through the soil pore skeleton and pore water to the pore water pressure gauge position of the other excitation measuring device in the excitation measuring pair. The propagation time of the vibration wave signal between the excitation measuring pair is obtained by performing a cross-correlation coefficient on the vibration wave signal and the pore water pressure response signal.

[0014] The vibration measurement pairs obtain the wave velocity of saturated soil at different center elevation depths based on the propagation time of the vibration wave signal between the vibration measurement pairs.

[0015] Furthermore, in the method for detecting sediment thickness, the propagation time of the vibration wave signal between the excitation measurement pairs is obtained by performing a cross-correlation coefficient on the vibration wave signal and the pore water pressure response signal, including:

[0016] The vibration measurement records the vibration wave signal as x(t) and the pore water pressure response as y(t). The cross-correlation coefficient of the discrete recorded signals is calculated according to the following formula:

[0017]

[0018] Where R is the cross-correlation coefficient, ts and N are the sampling interval and sampling length, respectively. Taking the maximum value of the cross-correlation coefficient yields the wave propagation time kt between the excitation measurement pairs. s .

[0019] Furthermore, in the method for detecting sediment thickness, the vibration measurement pair obtains the wave velocity of saturated soil at different center elevation depths based on the propagation time of the vibration wave signal between the vibration measurement pairs, including:

[0020] Based on the following formula, the first type of compressive wave velocity of the saturated soil between the excitation measurement pairs is obtained as follows:

[0021]

[0022] Where L is the distance between the two excitation measuring instruments in the vibration measurement pair.

[0023] Furthermore, in the method for detecting sediment thickness, determining the sediment location based on the soil parameter variation curves corresponding to different depths includes:

[0024] Based on the soil parameter variation curves at different depths, the center elevation depth of the unsaturated soil with significant changes in wave velocity is determined, which is the boundary between the sediment at the bottom of the trench or hole and the bearing layer of the diaphragm wall or bored pile.

[0025] Furthermore, in the method for detecting sediment thickness, determining the sediment location based on the soil parameter variation curves corresponding to different depths includes:

[0026] When the center elevation depth of significant changes in unsaturated soil wave velocity cannot be determined based on the soil parameter variation curves at different depths, the corresponding calculated soil modulus is calculated based on the unsaturated soil wave velocity at different depths. When the soil modulus at a certain center elevation depth reaches 90% to 100% of the soil modulus of the bearing layer, the overburden at that center elevation depth is determined as the boundary between the sediment at the bottom of the trench or hole and the bearing layer of the diaphragm wall or bored pile.

[0027] Compared with existing technologies, the device for detecting sediment thickness in this invention consists of an outer frame, an electric telescopic rod, a measuring rod, and a vibration measuring pair. In the process of constructing diaphragm walls or bored piles, after trenching or drilling is completed, sediment needs to be removed from the trench or hole through mud circulation. Controlling sediment thickness is a key construction step to ensure the vertical bearing capacity of diaphragm walls or bored piles. Accurate measurement of sediment thickness is significant for adjusting mud circulation and cleaning time and mud mixing process. This invention is applicable to sediment thickness detection during the construction of diaphragm walls and bored piles in construction projects. This invention targets sediment thickness detection after trenching or drilling during the construction of diaphragm walls and bored piles, controlling sediment thickness based on accurate measurement, improving the construction quality of diaphragm walls or bored piles, and ensuring that the vertical bearing capacity meets requirements. Attached Figure Description

[0028] Figure 1 This is a plan view of a device for detecting the thickness of sediment according to an embodiment of the present invention;

[0029] Figure 2 This is a cross-sectional view of a device for detecting sediment thickness according to an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the operation of a device for detecting sediment thickness according to an embodiment of the present invention. Detailed Implementation

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] like Figures 1 to 3 As shown, the present invention provides a device for detecting the thickness of sediment, comprising:

[0033] Outer frame 1;

[0034] The outer frame 1 contains two electric telescopic rods 2, two measuring rods 3, and a vibration measuring pair 4. The vibration measuring pair 4 includes two vibration measuring devices arranged opposite each other. The two electric telescopic rods 2 are arranged at intervals opposite each other. The electric telescopic rods 2 are connected to the outer frame 1. The lower part of each electric telescopic rod 2 is connected to a measuring rod 3. The lower part of each measuring rod 3 is equipped with one vibration measuring device from the vibration measuring pair 4.

[0035] Here, as Figures 1 to 3 As shown, the device for detecting sediment thickness according to the present invention consists of an outer frame, an electric telescopic rod, a measuring rod, and a vibration measuring pair. The present invention is applicable to sediment thickness detection during the construction process of underground continuous walls, bored piles, etc., in construction projects.

[0036] In the construction process of diaphragm walls or bored piles, after trenching or drilling is completed, sediment needs to be removed from the trench or hole through mud circulation. Controlling the sediment thickness is a key construction step to ensure the vertical bearing capacity of diaphragm walls or bored piles. Accurately measuring the sediment thickness is important for adjusting the mud circulation cleaning time and mud ratio process. This invention addresses the detection of sediment thickness after trenching or drilling during the construction of diaphragm walls and bored piles. Based on accurate measurement, it controls the sediment thickness, improves the construction quality of diaphragm walls or bored piles, and ensures that the vertical bearing capacity meets requirements.

[0037] In one embodiment of the apparatus for detecting sediment thickness of the present invention, each excitation measuring device includes: a vibration generator and a pore water pressure gauge.

[0038] Here, the distance between the two excitation measuring devices in the excitation measurement pair is L, and each excitation measuring device includes: a vibration generator and a pore water pressure gauge.

[0039] According to another aspect of the invention, such as Figures 1 to 3 As shown, the present invention also provides a method for detecting the thickness of sediment, using the apparatus for detecting the thickness of sediment described in any of the above embodiments, the method comprising:

[0040] Step S1: Lower the device for detecting the thickness of sediment to the bottom of the tank or the bottom of the hole;

[0041] Step S2: Using the electric telescopic rod 2, the measuring rod 3 and the vibration measuring pair 4 are pressed into the sediment and soil. During the downward movement of the measuring rod 3 and the vibration measuring pair 4, the center elevation depth d of the vibration measuring pair is recorded through the measuring rod, and the wave velocity v of the saturated soil at different center elevation depths d is recorded through the vibration measuring pair 4. p ;

[0042] Step S3: Measure the wave velocity v of the saturated soil at different center elevation depths d. pPlot the soil parameter variation curves at different depths, and determine the location of sediment based on these curves.

[0043] In this on-site application, after the device for detecting sediment thickness is lowered to the bottom of the trench or hole, the electric telescopic rod 2 is controlled to press the measuring rod 3 and the vibration measuring device 4 into the sediment and soil. During the descent, the measuring rod records the center elevation depth d of the vibration measuring device, and the vibration measuring device records the wave velocity v of the saturated soil in between. p By using the recorded dv data, curves showing the variation of soil parameters at different depths can be plotted to determine the location of sediment.

[0044] Here, the vibration wave propagates from the vibration generator of one excitation measuring device through the soil pore skeleton and pore water to the pore water pressure gauge position of another excitation measuring device. By performing cross-correlation analysis on the excitation signal and the pore water pressure response signal, the propagation time of the wave between the excitation measuring pairs can be obtained, and then the first-order compressive wave velocity of the saturated soil between the excitation measuring pairs can be calculated. During the lowering of the measuring rod, the burial depth of the excitation measuring pairs is recorded, forming a depth-saturated soil wave velocity relationship curve.

[0045] In one embodiment of the method for detecting sediment thickness of the present invention, step S2 involves measuring the wave velocity v of saturated soil at different center elevation depths d using vibration measurement. p ,include:

[0046] Step S21: The vibration wave signal propagates from the vibration generator of one excitation measuring device of the excitation measurement pair 4 through the soil pore skeleton and pore water to the pore water pressure gauge position of the other excitation measuring device of the excitation measurement pair 4. The propagation time of the vibration wave signal between the excitation measurement pair is obtained by performing a cross-correlation coefficient on the vibration wave signal and the pore water pressure response signal.

[0047] Step S22: Based on the propagation time of the vibration wave signal between the excitation measurement pairs 4, the wave velocity v of the saturated soil at different center elevation depths d is obtained. p .

[0048] In one embodiment of the method for detecting sediment thickness of the present invention, step S21, obtaining the propagation time of the vibration wave signal between the excitation measurement pairs by performing a cross-correlation coefficient on the vibration wave signal and the pore water pressure response signal, includes:

[0049] The vibration wave signal recorded by the excitation measurement is x(t), and the pore water pressure response is recorded as y(t). The cross-correlation coefficient of the discrete recorded signals is calculated according to the following formula:

[0050]

[0051] Where R is the cross-correlation coefficient, ts and N are the sampling interval and sampling length, respectively. Taking the maximum value of the cross-correlation coefficient yields the wave propagation time kt between the excitation measurement pairs. s .

[0052] In one embodiment of the method for detecting sediment thickness of the present invention, in step S22, the vibration measurement pair 4 obtains the wave velocity v of the saturated soil at different center elevation depths d based on the propagation time of the vibration wave signal between the vibration measurement pairs. p ,include:

[0053] Based on the following formula, the first-order compressive wave velocity v of the saturated soil between 4 points is obtained from the excitation measurement. p for:

[0054]

[0055] Where L is the distance between the two excitation measuring instruments in the vibration measurement pair.

[0056] Here, the wave velocity of saturated soil is related to the soil modulus, which are basic soil properties and can be used to deduce other parameters.

[0057] The soil property measurement results obtained by this device are the average results of the soil within a plane range between the vibration measurement pairs, which can effectively avoid errors caused by single-point measurements. The measurement distance L can be modified according to specific circumstances; a larger spacing can be achieved by using a larger excitation amplitude, ensuring that the vibration wave can be transmitted between the measurement excitation pairs.

[0058] In one embodiment of the method for detecting sediment thickness of the present invention, step S3, determining the sediment location based on the soil parameter variation curves corresponding to different depths, includes:

[0059] Based on the soil parameter variation curves at different depths, the wave velocity v of unsaturated soil was determined. p The location of the center elevation depth where there is a significant change is the boundary between the sediment at the bottom of the trench or hole and the bearing layer of the diaphragm wall or bored pile.

[0060] In one embodiment of the method for detecting sediment thickness of the present invention, step S3, determining the sediment location based on the soil parameter variation curves corresponding to different depths, includes:

[0061] When the wave velocity v of unsaturated soil cannot be determined based on the soil parameter variation curves at different depths, p When the center elevation depth position changes significantly, the wave velocity v is measured based on the corresponding unsaturated soil at different depths. pCalculate the corresponding soil modulus. When the soil modulus at a certain center elevation depth reaches 90% to 100% of the soil modulus of the bearing layer, the overburden at that center elevation depth is determined as the boundary between the sediment at the bottom of the trench or hole and the bearing layer of the diaphragm wall or bored pile.

[0062] There are two methods for determining the thickness of the sediment:

[0063] ①The location of significant changes in shear wave velocity can be determined directly by the changes in shear wave velocity at different depths, which is the boundary between the sediment at the bottom of the trench or hole and the bearing layer of the diaphragm wall or bored pile.

[0064] ② When the location of shear wave velocity change cannot be easily determined, the soil modulus can be calculated based on soil mechanics knowledge using soil wave velocity. When the soil modulus reaches a certain proportion of the bearing layer (such as 90% or 100%), the overlying soil is determined to be sediment and should be removed to ensure the vertical bearing capacity of the underground continuous wall or bored pile.

[0065] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0066] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0067] Obviously, those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A method for detecting the thickness of sediment, characterized in that, The method includes: The device for detecting sediment thickness is lowered to the bottom of the tank or the bottom of the hole; the device for detecting sediment thickness includes: an outer frame; two electric telescopic rods, two measuring rods, and a vibration measuring pair disposed within the outer frame, wherein the vibration measuring pair includes two vibration measuring devices disposed opposite to each other, the two electric telescopic rods are disposed at intervals opposite to each other, the electric telescopic rods are connected to the outer frame, the lower part of each electric telescopic rod is connected to a measuring rod, and the lower part of each measuring rod is respectively disposed of one vibration measuring device in the vibration measuring pair; each vibration measuring device includes: a vibration generator and a pore water pressure gauge; The measuring rod and the excitation measuring pair are pressed into the sediment and soil by an electric telescopic rod. During the downward movement of the measuring rod and the excitation measuring pair, the center elevation depth of the excitation measuring pair is recorded by the measuring rod, and the wave velocity of the saturated soil at different center elevation depths is recorded by the excitation measuring pair. Based on the recorded wave velocities of saturated soil at different center elevation depths, soil parameter variation curves at different depths are plotted, and the location of sediment is determined based on these soil parameter variation curves at different depths. Wave velocities in saturated soil at different center elevations were measured using vibration-induced measurements, including: The vibration wave signal propagates from the vibration generator of one excitation measuring device in the excitation measuring pair through the soil pore skeleton and pore water to the pore water pressure gauge position of the other excitation measuring device in the excitation measuring pair. The propagation time of the vibration wave signal between the excitation measuring pair is obtained by performing a cross-correlation coefficient on the vibration wave signal and the pore water pressure response signal. The vibration measurement pairs obtain the wave velocity of saturated soil at different center elevation depths based on the propagation time of the vibration wave signal between the vibration measurement pairs.

2. The method for detecting sediment thickness as described in claim 1, characterized in that, By performing a cross-correlation function on the vibration wave signal and the pore water pressure response signal, the propagation time of the vibration wave signal between the excitation measurement pairs is obtained, including: Excitation measurement records the vibration wave signal as x ( t The pore water pressure response was recorded as follows: y ( t The cross-correlation coefficient of the discrete recorded signal is calculated according to the following formula: , k =0, 1, 2, …, N -1 in, R For cross-correlation coefficients, ts and N The sampling interval and sampling length are respectively used. Taking the maximum value of the cross-correlation coefficient yields the wave propagation time between the excitation measurement pairs. kt s .

3. The method for detecting sediment thickness as described in claim 2, characterized in that, The vibration measurement pairs obtain the wave velocity of saturated soil at different center elevation depths based on the propagation time of the vibration wave signal between the vibration measurement pairs, including: Based on the following formula, the first type of compressive wave velocity of the saturated soil between the excitation measurement pairs is obtained as follows: ， in, L The distance between the two excitation measuring instruments in the vibration measurement pair.

4. The method for detecting sediment thickness as described in claim 1, characterized in that, Based on the soil parameter variation curves at different depths, the location of sediment was determined, including: Based on the soil parameter variation curves at different depths, the center elevation depth of the saturated soil with significant changes in wave velocity is determined, which is the boundary between the sediment at the bottom of the trench or hole and the bearing layer of the diaphragm wall or bored pile.

5. The method for detecting sediment thickness as described in claim 1, characterized in that, Determining the location of sediment based on the soil parameter variation curves at different depths includes: When the center elevation depth of significant changes in saturated soil wave velocity cannot be determined based on the soil parameter variation curves at different depths, the corresponding calculated soil modulus is calculated based on the saturated soil wave velocity at different depths. When the soil modulus at a certain center elevation depth reaches 90% to 100% of the soil modulus of the bearing layer, the overburden at that center elevation depth is determined as the boundary between the sediment at the bottom of the trench or hole and the bearing layer of the diaphragm wall or bored pile.

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