Method for monitoring clearance convergence of shaft wall of vertical shaft

Abstract

The invention discloses a method for monitoring clearance convergence of a shaft wall of a vertical shaft. The method comprises the following steps: (1) arranging three measurement marks serving as temporary reference points and monitoring points P1 and P2 at two ends of a convergence measuring line to be measured on the side wall of the shaft bottom of the vertical shaft; (2) respectively measuring the distance between every two of the three temporary datum points by using a total station; (3) respectively measuring the distances between the P1 and the three temporary reference points by using a total station; (4) establishing a space coordinate system, and calculating the coordinate of the P1 point; (5) respectively measuring the distances between the P2 and the three temporary reference points by using a total station; (6) calculating the coordinates of the P2 point according to the space coordinate system; (7) calculating the length L of a convergence measuring line according to the coordinates of the convergence measuring points P1 and P2; and (8) respectively measuring the length values of the convergence measuring line at different times to obtain the change L of the convergence measuring line. The difference between the convergence value measured by the method provided by the invention and the convergence value measured by the convergence meter is small, and the measurement precision can meet the precision requirement of convergence monitoring.

Description

Technical Field

[0001] The invention belongs to the technical field of vertical shaft wall convergence monitoring, and in particular relates to a vertical shaft wall clearance convergence monitoring method. Background Art

[0002] Vertical shaft engineering is an important part of subway construction. A vertical shaft is a well-shaped pipe with an upright hole wall; clearance convergence is also called clearance deformation, which refers to the phenomenon that the surrounding rock mass invades the vertical shaft clearance after the vertical shaft is excavated. It generally refers to the change in the relative position between two points on the vertical shaft wall. For subway projects constructed using the dark excavation method, the vertical shaft can not only be used as a permanent structure such as an air duct, but also as a temporary construction channel for transporting debris and materials. During the excavation of the vertical shaft, due to severe unloading, the surrounding rock and soil will displace into the vertical shaft, which will cause the support structure of the vertical shaft wall to deform or even crack and collapse. The clearance convergence of the vertical shaft wall can directly reflect the deformation of the shaft wall. Therefore, during the excavation of the vertical shaft, it is very necessary to monitor the clearance convergence of the vertical shaft wall.

[0003] At present, the instruments commonly used for monitoring the clearance convergence of the shaft wall mainly include convergence meters, total stations, handheld laser rangefinders, etc. When using a convergence meter for monitoring, the convergence meter needs to be hung on the convergence hook, and the convergence meter steel ruler needs to be manually tensioned for reading; when using a total station for monitoring, the station can be set freely, and the length of the convergence line can be directly measured using the side measurement function of the total station. It is necessary to observe the measuring points at both ends of the convergence line at the same station at the same time; when using a handheld laser rangefinder for monitoring, the rangefinder needs to be placed close to the shaft wall on one side of the shaft, and the reflective measurement mark on the other side of the shaft wall needs to be aimed at for reading.

[0004] However, during the shaft excavation process, the construction environment is extremely complex, and the above monitoring methods all have shortcomings. The use of convergence meters and handheld laser rangefinders for convergence monitoring requires surveyors to be able to reach the height of the convergence line. During the shaft excavation process, the elevation of the bottom of the shaft continues to drop, and the convergence line becomes higher and higher relative to the bottom of the shaft, and soon it cannot be measured, so the monitoring time is short. When using a total station to monitor the edge measurement, the measuring points at both ends of the convergence line need to be visible in the same measuring station. However, the space in the shaft is small, and it is difficult to find a station with visible conditions. At the same time, in order to ensure the safety of the primary support structure during the shaft excavation process, multiple layers of steel supports are set in the shaft, which seriously affects the visibility of the convergence monitoring points, making it more difficult to select a suitable total station station.

[0005] Due to the above shortcomings of the current commonly used vertical shaft convergence monitoring method, the monitoring data of the shaft wall clearance convergence is discontinuous and seriously missing during the vertical shaft excavation process, which cannot accurately reflect the deformation of the shaft wall and poses a great safety hazard. Therefore, it is very necessary to improve the existing convergence monitoring method and solve the problem of serious missing data of vertical shaft convergence monitoring. Summary of the invention

[0006] Aiming at the problem that the clearance convergence of shaft wall cannot be continuously monitored in the current subway monitoring field, the present invention proposes an indirect monitoring method based on the free station setting of total station, which can greatly increase the monitoring period of shaft clearance convergence and improve the monitoring efficiency, so as to solve the problem that there is no data on the clearance convergence of shaft wall for a long time during shaft excavation.

[0007] The present invention achieves this object through the following technical solutions:

[0008] A method for monitoring the clearance convergence of a shaft wall comprises the following steps:

[0009] (1) Set three measurement marks A, B, and C as temporary reference points on the side wall of the shaft bottom and monitoring points P1 and P2 at both ends of the convergence line to be measured;

[0010] (2) Select a suitable location to set up a total station, and use the total station to measure the distance c between the two temporary reference points AB, the distance a between the two temporary reference points BC, and the distance b between the two temporary reference points AC;

[0011] (3) Find a suitable location at the bottom of the shaft to set up the total station, ensure that the convergence point P1 has line of sight with the temporary reference points A, B, and C, and measure the distance S between the convergence point P1 and A, B, and C respectively. a1 , S b1 , S c1 ;

[0012] (4) Establish a spatial coordinate system and calculate the coordinates (x1, y1, z1) of the convergence point P1 based on the positional relationship between the convergence point P1 and the temporary reference points A, B, and C;

[0013] (5) Find a suitable location at the bottom of the shaft to re-set up the total station, ensure that the convergence point P2 has line of sight with the temporary reference points A, B, and C, and measure the distance S from the convergence point P2 to the temporary reference points A, B, and C respectively. a2 , S b2 , S c2 ;

[0014] (6) Referring to the rectangular coordinate system established in step (4), the coordinates (x2, y2, z2) of the convergence point P2 are calculated according to the positional relationship between the convergence point P2 and the temporary reference points A, B, and C;

[0015] (7) Calculate the length L of the convergence line according to the coordinates of the convergence points P1 and P2:

[0016]

[0017] (8) According to steps (1) to (7), the length of the convergence line is measured at different times to obtain the change ΔL of the convergence line, ΔL=L2-L1, where L1 and L2 are the measured values ​​of the convergence lines before and after respectively.

[0018] Furthermore, the step (4) is specifically as follows: establish a spatial rectangular coordinate system with point A as the origin, the straight line where points AB are located is the x-axis, the normal direction of the plane where points ABC are located is the z-axis, the coordinates of point A are (0,0,0), the coordinates of point B are (c,0,0), and the coordinates of point C are (x C ,y C , 0), where x C =(b 2 -a 2 +c 2 ) / 2·c, The coordinates of the convergence point P1 are (x1, y1, z1), where x1 = (S a1 2 -S b1 2 +c 2 ) / 2·c,

[0019] Furthermore, the calculation formula for the coordinates of point P2 in step (6) is as follows:

[0020] x2=(S a2 2 -S b2 2 +c 2 ) / 2·c,

[0021] Furthermore, the measurement mark of the temporary reference point adopts a small prism or a reflective sheet.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] Without increasing on-site production costs, the present invention can greatly extend the monitoring period of shaft wall clearance convergence, solve the problem of long-term lack of shaft wall clearance convergence monitoring data during the current shaft excavation process, and provide strong guarantee for the safe construction of the shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0025] Figure 1 It is a schematic diagram of the process of the present invention;

[0026] Figure 2 This is a schematic diagram of the measurement points of the present invention;

[0027] Figure 3 This is the measurement diagram of the convergence point P1;

[0028] Figure 4 Measure the geometric relationship diagram for the convergence point P1;

[0029] Figure 5 To construct a schematic diagram of the spatial coordinate system;

[0030] Figure 6 This is a schematic diagram of the measurement of the convergence point P2. DETAILED DESCRIPTION

[0031] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to be able to fully convey the scope of the present invention to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0032] The present invention proposes an indirect monitoring method based on free station setting of total station, the process is as follows: Figure 1 As shown, the method comprises the following steps:

[0033] (1) Set three measurement marks and convergence monitoring points as temporary reference points on the side wall of the shaft bottom. Figure 2 As shown in the figure, A, B, and C are temporary reference points, and P1 and P2 are monitoring points at both ends of the convergence line to be measured. The measurement mark of the temporary reference point can be a small prism or a reflector. The position of the temporary reference point needs to be fixed during the entire measurement process.

[0034] (2) Select a suitable location to set up a total station, and use the total station to measure the distance c between the two temporary reference points AB, the distance a between the two temporary reference points BC, and the distance b between the two temporary reference points AC.

[0035] (3) Find a suitable location at the bottom of the shaft to set up the total station, ensure that the convergence point P1 has line of sight with the temporary reference points A, B, and C, and measure the distance S between the convergence point P1 and A, B, and C respectively. a1 , S b1 , S c1 ,like Figure 3 shown.

[0036] (4) Calculate the coordinates of the convergence point P1. The geometric relationship between P1 and the temporary reference point is as follows: Figure 4 As shown. Figure 5 The spatial rectangular coordinate system shown in the figure has A as the origin, the line AB is the x-axis, and the normal direction of the plane ABC is the z-axis. Then the coordinates of point A are (0,0,0), and the coordinates of point B are (c,0,0). Let the coordinates of point C be (x C ,y C , 0), the distance between point B and point C is a, and the distance between point A and point C is b, then the following equation is satisfied:

[0037]

[0038] x A =0,y A =0,x B =c,y B =0, substitute them into the above formula and solve the equations to get

[0039]

[0040] Subtracting formula ③ from formula ④ yields

[0041] 2·c·x C -c 2 =b 2 -a 2

[0042] x C =(b 2 -a 2 +c 2 ) / 2·c ⑤

[0043] Substituting equation ⑤ into equation ④, we can get

[0044]

[0045] Assume the coordinates of the convergence point P1 are (x1, y1, z1). Figure 4 The geometric relationship in the equations can be obtained as follows:

[0046]

[0047] x A =0,y A =0,x B =c,y B =0,z A =0,z B =0,z C =0 Substituting into the above equations, we can get

[0048]

[0049] Subtracting equation ⑧ from equation ⑦ yields

[0050] 2·c·x1-c 2 =S a1 2 -S b1 2

[0051] x1=(S a1 2 -S b1 2 +c 2 ) / 2·c ⑩

[0052] Subtracting equation ⑦ from equation 9 yields

[0053]

[0054] Bring formula ④ into formula Available

[0055]

[0056] From formula ⑦, we can get

[0057]

[0058] (5) Find a suitable location at the bottom of the shaft to re-set up the total station, ensure that the convergence point P2 has line of sight with the temporary reference points A, B, and C, and measure the distance S from the convergence point P2 to the temporary reference points A, B, and C respectively. a2 , S b2 , S c2 ,like Figure 6 shown.

[0059] (6) Calculate the coordinates of the convergence point P2 by referring to step (4), and the calculation formula of the coordinates of point P2 can be obtained:

[0060] x2=(S a2 2 -S b2 2 +c 2 ) / 2·c

[0061]

[0062] (7) Calculate the length L of the convergence line according to the coordinates of the convergence points P1 and P2:

[0063]

[0064] (8) According to the above method, the length of the convergence line is measured at different times to obtain the convergence change value. △L is the change value of the convergence measurement line, and L1 and L2 are the measurement values ​​of the two convergence measurement lines respectively.

[0065] ΔL=L2-L1

[0066] Three convergence measurement lines are selected to verify the above method. The three convergence measurement lines are the last convergence in the vertical direction of the shaft and are close to the bottom of the shaft. Convergence meters can be used for monitoring. First, the length of the convergence measurement line is measured by the method proposed in the present invention, and then the length of the convergence measurement line is measured by the convergence meter. The measurement results of the two methods are compared. The comparison results are shown in Table 1.

[0067] In Table 1, a, b, and c are the lengths of the sides between temporary reference points, S a1 , S b1 , S c1 , S a2 , S b2 , S c2 are the distances from the measuring points at both ends of the convergence measurement line to each temporary reference point, L' is the convergence value measured by the new method, and L is the convergence value measured by the convergence meter. By comparing the difference between L' and L, it can be seen that the difference between the convergence value measured by the method proposed in the present invention and the convergence value measured by the convergence meter is small, and the measurement accuracy can meet the accuracy requirements of convergence monitoring.

[0068] Table 1 Comparison of measurement results accuracy

[0069]

[0070] The present invention has been described in detail above through embodiments, but the contents described are only exemplary embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. The protection scope of the present invention is defined by the claims. Anyone who utilizes the technical solution described in the present invention, or a technician in the field, inspired by the technical solution of the present invention, designs a similar technical solution within the essence and protection scope of the present invention to achieve the above technical effects, or makes equal changes and improvements to the scope of application, shall still belong to the scope of protection covered by the patent of the present invention. It should be noted that in order to make a clear statement, the description of some components and processes that have no direct and obvious connection with the scope of protection of the present invention but are known to those skilled in the art are omitted in the description of the present invention.

Claims

1. A method for monitoring the clearance convergence of a vertical shaft wall, characterized in that: The following steps are involved: (1) Set three measurement marks A, B, and C as temporary reference points on the side wall of the shaft bottom and monitoring points P1 and P2 at both ends of the convergence line to be measured; (2) Select a suitable location to set up a total station, and use the total station to measure the distance c between the two temporary reference points AB, the distance a between the two temporary reference points BC, and the distance b between the two temporary reference points AC; (3) Find a suitable location at the bottom of the shaft to set up the total station, ensure that the convergence point P1 has line of sight with the temporary reference points A, B, and C, and measure the distance S between the convergence point P1 and A, B, and C respectively. a1 , S b1 , S c1 ; (4) Establish a spatial coordinate system and calculate the coordinates (x1, y1, z1) of the convergence point P1 based on the positional relationship between the convergence point P1 and the temporary reference points A, B, and C; (5) Find a suitable location at the bottom of the shaft to re-set up the total station, ensure that the convergence point P2 has line of sight with the temporary reference points A, B, and C, and measure the distance S from the convergence point P2 to the temporary reference points A, B, and C respectively. a2 , S b2 , S c2 ; (6) Referring to the rectangular coordinate system established in step (4), the coordinates (x2, y2, z2) of the convergence point P2 are calculated according to the positional relationship between the convergence point P2 and the temporary reference points A, B, and C; (7) Calculate the length L of the convergence line according to the coordinates of the convergence points P1 and P2: (8) According to steps (1) to (7), the length of the convergence line is measured at different times to obtain the change ΔL of the convergence line, ΔL=L2-L1, where L1 and L2 are the measured values ​​of the convergence lines before and after respectively.

2. A method for monitoring the clearance convergence of a vertical shaft wall according to claim 1, characterized in that: The step (4) is specifically as follows: a spatial rectangular coordinate system is established with point A as the origin, the straight line where points AB are located is the x-axis, the normal direction of the plane where points ABC are located is the z-axis, the coordinates of point A are (0,0,0), the coordinates of point B are (c,0,0), and the coordinates of point C are (x C ,y C , 0), where x C =(b 2 -a 2 +c 2 ) / 2·c, The coordinates of the convergence point P1 are (x1, y1, z1), where x1 = (S a1 2 -S b1 2 +c 2 ) / 2·c, 3. A method for monitoring the clearance convergence of a vertical shaft wall according to claim 2, characterized in that: The calculation formula of the coordinates of point P2 in step (6) is as follows: x2=(S a2 2 -S b2 2 +c 2 ) / 2·c, 4. A method for monitoring the clearance convergence of a vertical shaft wall according to any one of claims 1 to 3, characterized in that: The measurement mark of the temporary reference point is a small prism or a reflective sheet.

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