A method, system and device for measuring horizontal displacement of foundation pit

Abstract

The invention relates to a method, system and device for measuring the horizontal displacement of a foundation pit. Monitoring points are set in layers on the inner wall of the foundation pit by using optical fibers, thereby eliminating errors caused by reference points. The scheme eliminates the need to use monitoring reference points as reference points for measurement and calculation, thereby simplifying the measurement process and eliminating errors caused by displacement changes of monitoring reference points. There is no need to rely on monitoring reference points for data conversion, thereby further saving the calculation process. Instead, the inclination angle of each monitoring point is directly measured by using optical fibers, thereby ensuring the real-time and accuracy of the data and improving the measurement accuracy.

Description

Technical Field

[0001] The invention relates to the field of foundation pit monitoring, and in particular to a method, system and device for measuring horizontal displacement of a foundation pit. Background Art

[0002] Foundation pit monitoring is an important part of foundation pit construction. It refers to various observations and analyses of changes in foundation pit rock and soil properties, support structure displacement and surrounding environmental conditions during foundation pit excavation and underground engineering construction. The monitoring results are fed back in a timely manner to predict the deformation and stable state development that will result from further construction. The degree of impact of the construction on the surrounding environment is determined based on the prediction to guide the design and construction, thus realizing the so-called information-based construction.

[0003] The core of foundation pit monitoring is horizontal displacement monitoring, that is, monitoring whether there is a sinkhole in the foundation pit, so as to avoid collapse events. At present, the sight line method, small angle method, point casting method, etc. can be used to measure the horizontal displacement in a specific direction; the distribution of the monitoring point can be used to measure the horizontal displacement of the monitoring point in any direction, and the forward intersection method, free station method, polar coordinate method, etc. can be used; when the benchmark point is far away from the foundation pit, the GPS measurement method or the comprehensive measurement method combining triangulation, three sides, and corner measurement with the benchmark method can be used. When the monitoring accuracy requirement is relatively high, micro-deformation measurement radar can be used for automatic all-weather real-time monitoring. The horizontal displacement monitoring benchmark point should be buried in a stable area that is not affected by construction outside the range of 3 times the excavation depth of the foundation pit, or use the existing stable construction control point. It should not be buried in the influence range of low-lying water accumulation, wet collapse, frost heave, expansion and contraction; the burial of the benchmark point should be carried out in accordance with relevant measurement specifications and procedures. It is advisable to set up an observation pier with forced centering; use a precise optical centering device, and the centering error should not be greater than 0.5mm.

[0004] There is a common defect in the existing measurement method, that is, the setting of the monitoring reference point is generally set on the ground. However, at the construction site, ground deformation is a common occurrence. Therefore, as long as the reference point is set on the ground, the absoluteness of the reference point cannot be guaranteed, which affects the measurement accuracy. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method, system and device for measuring the horizontal displacement of a foundation pit. In this scheme, there is no need to select a reference point for measuring the horizontal displacement of the foundation pit, thereby eliminating the error caused by the reference point, and directly measuring the monitoring point, thereby improving the monitoring accuracy.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A method for measuring horizontal displacement of a foundation pit, the method comprising:

[0008] Step 1: Select multiple monitoring points around the foundation pit. The monitoring points are set in layers with different depths, that is, multiple circles of monitoring points are set in layers at different heights on the inner wall of the foundation pit. The number of layers represents the number of monitoring points, and the number of monitoring points in that layer represents the sequence number of the monitoring points.

[0009] Step 2: Drill holes horizontally and deeply around each monitoring point, cast the monitoring point foundation column, and extend the monitoring point foundation column horizontally and deeply to form a stable support point. The number of support points is at least 4, and a symmetrical structure distribution with the monitoring point as the center is adopted;

[0010] Step 3: An optical fiber tube for detecting micro deformation is arranged between each set of symmetrical support points. All optical fiber tubes at the same monitoring point are centered on the monitoring point. Multiple optical fiber tubes are connected and connected at the monitoring point to form a whole, and the collection point is tightly abutted against the monitoring point.

[0011] Step 4: Receive the deformation data of the optical fiber tube in real time to obtain the deformation variable of the monitoring point in the multi-dimensional direction in the vertical plane. The deformation variable is the indentation amount of the monitoring point in the multi-dimensional direction in the vertical plane, that is, the horizontal displacement of the monitoring point.

[0012] Unlike traditional monitoring methods, this scheme does not require the setting of reference points. Instead, monitoring point base columns are set in the horizontal and vertical directions around the monitoring points to fix the optical fiber tubes that can monitor subtle deformations. Through layered settings, the inclination changes of each monitoring point on the same vertical line can be determined, and then converted into horizontal movement of the inner wall of the foundation pit, thereby simplifying the measurement process and eliminating the errors caused by the monitoring base points.

[0013] Furthermore, the depth of the monitoring point column should be greater than 1 meter, and the reverse ends of the monitoring point columns are fixed on the same base. This design can ensure that the data measured by the optical fiber tube on the same diagonal line is more accurate and avoid displacement of the measuring point column. However, in some actual operations, when the foundation pit is deep and it is not easy to drill the building casting base, this structure can be omitted.

[0014] Furthermore, the horizontal spacing between adjacent monitoring points shall not exceed 5 meters, and the vertical spacing shall not exceed 3 meters.

[0015] Furthermore, the span between each set of symmetrical support points is 50-80cm, and it is ensured that in the initial state, the base columns of each monitoring point are parallel to each other, their front ends are aligned and located in the same vertical plane, and the alignment error does not exceed 0.1mm.

[0016] Furthermore, in step 4, when measuring the deformation of the monitoring point in multiple directions in the vertical plane, the deformation of the optical fiber tube is converted into the change in the inclination angle of the optical fiber tube. In the initial state, each optical fiber tube is parallel to the vertical plane, that is, the initial angle is 90°. The inclination angle of the monitoring point in multiple directions in the vertical plane is determined according to the change in the inclination angle of the optical fiber tube in multiple directions, and then converted into the horizontal displacement of the monitoring point. That is to say, in this scheme, whether the data is accurate is judged based on whether the inclination changes of each monitoring point at the same latitude in the vertical plane are consistent. Since when the foundation pit sinks, it must be an overall sinking, so the reflection on the monitoring point is that each monitoring point sinks as a whole, or several consecutive monitoring points (that is, a section of the foundation pit within a certain height difference) sink. The amount of sinking (that is, the horizontal displacement) at different heights is obviously different. Generally speaking, the displacement of the upper layer must be greater than that of the lower layer, but their inclination angles are the same. This scheme uses the inclination angle to make judgments.

[0017] Furthermore, it also includes a data correction process, that is, calculating whether the indentation angles of each monitoring point on the same vertical line are consistent within the error range. If the indentation angles of each monitoring point or several adjacent continuous monitoring points on the vertical line are consistent within the error range, the data is considered valid. Otherwise, if the indentation angles of each monitoring point are distributed in discrete values, the data is considered invalid.

[0018] A foundation pit horizontal displacement measurement system, the system comprising:

[0019] Optical fiber tubes for measuring deformation at monitoring points, the optical fiber tubes are distributed at the monitoring points in a symmetrical cross structure;

[0020] A communication module for transmitting real-time data of the optical fiber tube, and for uploading the deformation data of the optical fiber tube;

[0021] A host computer for receiving and processing data, the host computer receives the deformation data of the optical fiber tube, establishes a rectangular coordinate system with the vertical plane as the Y axis and the horizontal plane as the X axis, and calculates the linear equation of the optical fiber tube according to the deformation data of the optical fiber tube, and obtains the slope of the optical fiber tube, that is, the inclination angle of the side wall of the foundation pit where the monitoring point is located;

[0022] The data is corrected based on whether the multi-dimensional tilt angles measured at each monitoring point or several consecutive monitoring points on the same vertical line are consistent, and the data that does not meet the correction conditions is deleted.

[0023] The communication module uses an optical fiber communication module to upload data in real time.

[0024] A foundation pit horizontal displacement measuring device, the device comprising:

[0025] A vertical substrate is set at the horizontal depth of the monitoring point, and each monitoring point on the same vertical line uses the same vertical substrate;

[0026] The monitoring point base columns are vertically fixed on the vertical base plate, with the same monitoring point as the center, and at least four or more even number of monitoring point base columns are symmetrically distributed, and the front ends of the monitoring point base columns are aligned;

[0027] The optical fiber tubes are arranged at the front end of the monitoring point pillars, and are cross-distributed in a centrally symmetrical manner. Both ends of the optical fiber tubes on the same diagonal are respectively fixed at the front end of a monitoring point pillar. In the fixed state, the optical fiber tubes fit the inner wall of the foundation pit.

[0028] The number of the monitoring point columns is six, and correspondingly, the optical fiber tube is a "M"-shaped structure, which can not only measure the inclination of the monitoring point in the vertical direction, but also measure the inclination changes of the horizontal angle and the oblique 45° angle respectively.

[0029] The beneficial effects of the present invention are as follows: compared with the traditional measurement method, the present solution eliminates the need to use the monitoring reference point as a reference point for measurement and calculation, thereby simplifying the measurement process and eliminating the error caused by the displacement change of the monitoring reference point. There is no need to rely on the monitoring reference point for data conversion, thereby further saving the calculation process. Instead, the inclination of each monitoring point is directly measured using optical fiber, thereby ensuring the real-time and accuracy of the data and improving the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A top view of the monitoring system for the invention;

[0031] Figure 2 This is a schematic diagram of the inner wall of the foundation pit under monitoring status;

[0032] Figure 3 It is a schematic structural diagram of one embodiment of an optical fiber tube. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the following.

[0034] A method for measuring horizontal displacement of a foundation pit, the method comprising:

[0035] Step 1: Select multiple monitoring points around the foundation pit. The monitoring points are set in layers at different depths, that is, multiple circles of monitoring points are set at different heights on the inner wall of the foundation pit. The number of layers represents the number of monitoring points in the layer. The distribution method can be referred to Figure 1 As shown, first select monitoring points around the foundation pit. After the selection is completed, take each monitoring point as the starting point and extend vertically downward. Set monitoring points in layers on the extension line. The principle is as follows Figure 2 shown.

[0036] Step 2: Drill holes horizontally and deeply around each monitoring point, cast the monitoring point foundation column, and extend the monitoring point foundation column horizontally and deeply to form a stable support point. The number of support points is at least 4, and a symmetrical structure distribution with the monitoring point as the center is adopted;

[0037] Step 3: An optical fiber tube for detecting micro deformation is set between each set of symmetrical support points. All optical fiber tubes at the same monitoring point are centered on the monitoring point. Multiple optical fiber tubes are connected and conducted at the monitoring point to form a whole, and the collection point is tightly against the monitoring point. In other words, multiple optical fiber tubes are made in an integrated manner, and their centers are gathered to form a centrally symmetrical cross structure, which is at least a cross shape, that is, only four support points are set. Figure 3 Shown is a schematic diagram of a structure using three optical fiber tubes crossing each other.

[0038] Step 4: Receive the deformation data of the optical fiber tube in real time to obtain the deformation variable of the monitoring point in the multi-dimensional direction in the vertical plane. The deformation variable is the indentation amount of the monitoring point in the multi-dimensional direction in the vertical plane, that is, the horizontal displacement of the monitoring point.

[0039] Furthermore, the depth of the monitoring point columns should be greater than 1 meter, and the reverse ends of the monitoring point columns are fixed on the same base.

[0040] Furthermore, the horizontal spacing between adjacent monitoring points shall not exceed 5 meters, and the vertical spacing shall not exceed 3 meters.

[0041] Furthermore, the span between each set of symmetrical support points is 50-80cm, and it is ensured that in the initial state, the base columns of each monitoring point are parallel to each other, their front ends are aligned and located in the same vertical plane, and the alignment error does not exceed 0.1mm.

[0042] Furthermore, in step 4, when measuring the deformation of the monitoring point in multiple directions in the vertical plane, the deformation of the optical fiber tube is converted into the inclination change of the optical fiber tube. In the initial state, each optical fiber tube is parallel to the vertical plane, that is, the initial angle is 90°. The inclination angle of the monitoring point in multiple directions in the vertical plane is determined according to the inclination change of the optical fiber tube in multiple directions, and then converted into the horizontal displacement of the monitoring point.

[0043] Furthermore, it also includes a data correction process, that is, calculating whether the indentation angles of each monitoring point on the same vertical line are consistent within the error range. If the indentation angles of each monitoring point or several adjacent continuous monitoring points on the vertical line are consistent within the error range, the data is considered valid. Otherwise, if the indentation angles of each monitoring point are distributed in discrete values, the data is considered invalid.

[0044] A foundation pit horizontal displacement measurement system, the system comprising:

[0045] Optical fiber tubes 4 for measuring deformation of monitoring points 3, the optical fiber tubes 4 are distributed on the monitoring points 3 in a symmetrical cross structure;

[0046] A communication module for transmitting real-time data of the optical fiber tube 4, and for uploading deformation data of the optical fiber tube 4;

[0047] A host computer for receiving and processing data, the host computer receives the deformation data of the optical fiber tube 4, establishes a rectangular coordinate system with the vertical plane as the Y axis and the horizontal plane as the X axis, and calculates the straight line equation of the optical fiber tube 4 according to the deformation data of the optical fiber tube 4, and obtains the slope of the optical fiber tube 4, that is, the inclination angle of the side wall of the foundation pit where the monitoring point is located;

[0048] The data is corrected based on whether the multi-dimensional tilt angles measured at each monitoring point or several consecutive monitoring points on the same vertical line are consistent, and the data that does not meet the correction conditions is deleted.

[0049] The communication module uses a fiber optic communication module to upload data in real time.

[0050] like Figure 1-3 As shown, a foundation pit horizontal displacement measuring device, the device comprises:

[0051] A vertical substrate 2 is arranged in the horizontal depth of the monitoring point 3, and each monitoring point 3 on the same vertical line uses the same vertical substrate 2;

[0052] The monitoring point base columns 1 are vertically fixed on the vertical base plate 2. With the same monitoring point as the center, at least four or more even number of monitoring point base columns 1 are symmetrically distributed, and the front ends of the monitoring point base columns 1 are aligned;

[0053] The optical fiber tube 4 is arranged at the front end of the monitoring point column 1, and the optical fiber tube 4 is cross-distributed in a centrally symmetrical manner. Both ends of the optical fiber tube 4 on the same diagonal line are respectively fixed to the front end of a monitoring point column 1. In the fixed state, the optical fiber tube 4 fits against the inner wall of the foundation pit.

[0054] There are six monitoring point pillars 1, and correspondingly, the optical fiber tube 4 is a "M"-shaped structure.

[0055] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for measuring horizontal displacement of a foundation pit, characterized in that: The method includes: Step 1: Select multiple monitoring points around the foundation pit. The monitoring points are set in layers at different depths, that is, multiple circles of monitoring points are set in layers at different heights on the inner wall of the foundation pit; Step 2: Drill holes in the horizontal and vertical directions around each monitoring point and cast the monitoring point foundation column. The monitoring point foundation column extends in the horizontal direction to form a stable support point. The number of support points is at least 4, and a symmetrical structure distribution with the monitoring point as the center is adopted; Step 3: An optical fiber tube for detecting micro deformation is arranged between each set of symmetrical support points. All optical fiber tubes at the same monitoring point are centered on the monitoring point. Multiple optical fiber tubes are connected and conducted at the monitoring point to form a whole. The whole gathering point where multiple optical fiber tubes are connected and conducted at the monitoring point is tightly in contact with the monitoring point. Step 4: Receive the deformation data of the optical fiber tube in real time to obtain the deformation variable of the monitoring point in the multi-dimensional direction in the vertical plane. The deformation variable is the indentation amount of the monitoring point in the multi-dimensional direction in the vertical plane, that is, the horizontal displacement of the monitoring point.

2. A method for measuring horizontal displacement of a foundation pit according to claim 1, characterized in that: The depth of the monitoring point base column should be greater than 1 meter, and the reverse ends of the base columns of each monitoring point should be fixed on the same base.

3. A method for measuring horizontal displacement of a foundation pit according to claim 2, characterized in that: The horizontal distance between adjacent monitoring points shall not exceed 5 meters, and the vertical distance shall not exceed 3 meters.

4. A method for measuring horizontal displacement of a foundation pit according to claim 3, characterized in that: The span between each set of symmetrical support points is 50-80cm, and it is ensured that in the initial state, the base columns of each monitoring point are parallel to each other, their front ends are aligned in the same vertical plane, and the alignment error does not exceed 0.1mm.

5. A method for measuring horizontal displacement of a foundation pit according to claim 4, characterized in that: In step 4, when measuring the deformation amount of the monitoring point in multiple directions in the vertical plane, the deformation amount of the optical fiber tube is converted into the inclination change of the optical fiber tube. In the initial state, each optical fiber tube is parallel to the vertical plane, that is, the initial angle is 90°. The inclination angle of the monitoring point in multiple directions in the vertical plane is determined according to the inclination change of the optical fiber tube in multiple directions, and then converted into the horizontal displacement of the monitoring point.

6. A method for measuring horizontal displacement of a foundation pit according to claim 5, characterized in that: It also includes a data correction process, which is to calculate whether the indentation angles of each monitoring point on the same vertical line are consistent within the error range. If the indentation angles of each monitoring point or several adjacent continuous monitoring points on the vertical line are consistent within the error range, the data is considered valid. Otherwise, if the indentation angles of each monitoring point are distributed in discrete values, the data is considered invalid.

7. A foundation pit horizontal displacement measurement system, applied to the foundation pit horizontal displacement measurement method according to any one of claims 1 to 6, characterized in that: The system includes: Optical fiber tubes (4) for measuring deformation amounts at monitoring points (3), the optical fiber tubes (4) being distributed on the monitoring points (3) in a symmetrical cross structure; A communication module for transmitting real-time data of the optical fiber tube (4), and for uploading deformation data of the optical fiber tube (4); A host computer for receiving and processing data, the host computer receiving the deformation data of the optical fiber tube (4), establishing a rectangular coordinate system with the vertical plane as the Y axis and the horizontal plane as the X axis, and calculating the straight line equation of the optical fiber tube (4) based on the deformation data of the optical fiber tube (4), and obtaining the slope of the optical fiber tube (4), that is, the inclination angle of the side wall of the foundation pit where the monitoring point is located; The data is corrected based on whether the multi-dimensional tilt angles measured at each monitoring point or several consecutive monitoring points on the same vertical line are consistent, and the data that does not meet the correction conditions is deleted.

8. A foundation pit horizontal displacement measurement system according to claim 7, characterized in that: The communication module uses an optical fiber communication module to upload data in real time.

9. A foundation pit horizontal displacement measuring device, applied to the foundation pit horizontal displacement measuring method according to any one of claims 1 to 6, characterized in that: The device includes: A vertical substrate (2) is arranged in the horizontal and vertical direction of the monitoring point (3), and each monitoring point (3) on the same vertical line uses the same vertical substrate (2); A monitoring point base column (1) vertically fixed on a vertical base plate (2), with at least four or more even-numbered monitoring point base columns (1) symmetrically arranged around the same monitoring point, with front ends of the monitoring point base columns (1) aligned; The optical fiber tubes (4) are arranged at the front end of the monitoring point base column (1), and the optical fiber tubes (4) are cross-distributed in a centrally symmetrical manner. The two ends of the optical fiber tubes (4) on the same diagonal line are respectively fixed to the front end of a monitoring point base column (1). In the fixed state, the optical fiber tubes (4) are in contact with the inner wall of the foundation pit.

10. The device for measuring horizontal displacement of a foundation pit according to claim 9, characterized in that: The number of the monitoring point base columns (1) is six, and correspondingly, the optical fiber tube (4) is a "M"-shaped structure.

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