CN105222714A - A kind of method improving total powerstation Opposite side survey tunnel clearance convergence precision - Google Patents

本发明涉及一种提高隧道净空收敛量测精度的方法，具体涉及一种提高全站仪对边测量隧道净空收敛精度的方法。其采用全站仪对边量测法，基于两车道、三车道和四车道公路隧道实际断面大小，及现场净空收敛量测实际情况，通过选择合理的全站仪架设位置，提高量测精度。本发明采用的方法步骤为：首先，将两监测点左右对称布设在监测断面最大开挖线处，并进行保护，避免监测点在隧道施工中被影响破坏；然后，选择合理位置架设全站仪，最后，利用全站仪对边测量功能完成量测数据读取，并在每一次量测完成后恢复测点保护。

The invention relates to a method for improving the measurement accuracy of tunnel clearance convergence, in particular to a method for improving the convergence accuracy of tunnel clearance measurement by a total station on the opposite side. It adopts the side-to-side measurement method of the total station, based on the actual section size of the two-lane, three-lane and four-lane highway tunnels, and the actual situation of the on-site clearance convergence measurement, and improves the measurement accuracy by selecting a reasonable total station erection position. The steps of the method adopted in the present invention are as follows: firstly, the two monitoring points are symmetrically arranged at the maximum excavation line of the monitoring section, and protected to prevent the monitoring points from being affected and damaged during tunnel construction; then, a reasonable position is selected to erect the total station , and finally, use the side-to-side measurement function of the total station to complete the measurement data reading, and restore the measurement point protection after each measurement is completed.

一种提高全站仪对边测量隧道净空收敛精度的方法A Method of Improving the Convergence Accuracy of Total Station Measuring Tunnel Clearance from Side to Side

一、技术领域：1. Technical field:

本发明涉及一种提高隧道净空收敛量测精度的方法，具体涉及一种提高全站仪对边测量隧道净空收敛精度的方法。The invention relates to a method for improving the measurement accuracy of tunnel clearance convergence, in particular to a method for improving the convergence accuracy of tunnel clearance measurement by a total station on the opposite side.

二、背景技术：2. Background technology:

净空收敛是隧道监控量测的必测项目，是隧道围岩应力状态变化最直接的反映。目前公路隧道净空收敛主要采用收敛计进行量测，但该量测方法效率低，而且常与现场施工相互干扰。如隧道采用拱部留核心土环形开挖时，在核心土未开挖前，由于核心土的阻挡，收敛计无法沿断面水平测线对边展开完成量测，造成变形初测的滞后，引起一部分甚至是一大部分前期隧道围岩变形信息的丢失，因此监测结果不能真实完整地反映隧道围岩变形情况。同样，现场收敛计接触量测的进行对隧道施工的正常开展也存在一定的妨碍，影响隧道施工进度。随着目前大断面长隧道的日益增多，施工方法多变，传统的收敛计接触量测方法已经无法满足现代长大隧道快速安全的施工要求。因此，一种快速、简便、受隧道施工影响小的非接触量测方法——全站仪对边测量法，已被逐渐引入到隧道净空收敛监控量测中。但是，目前关于该测量方法的量测精度研究相对较少，没有较为明确的结论作为现场测量的依据，提高测量精度。Clearance convergence is a must-test item for tunnel monitoring and measurement, and it is the most direct reflection of changes in the stress state of the tunnel surrounding rock. At present, the clearance convergence of highway tunnels is mainly measured by the convergence gauge, but this measurement method is inefficient and often interferes with the on-site construction. For example, when the tunnel is excavated circularly with the core soil left at the arch, before the core soil is excavated, due to the blockage of the core soil, the extensometer cannot be deployed along the opposite side of the horizontal measurement line of the section to complete the measurement, resulting in a lag in the initial deformation measurement, causing A part or even a large part of the previous tunnel surrounding rock deformation information is lost, so the monitoring results cannot truly and completely reflect the tunnel surrounding rock deformation. Similarly, the on-site extensometer contact measurement also hinders the normal development of tunnel construction and affects the progress of tunnel construction. With the increasing number of long tunnels with large cross-sections and changing construction methods, the traditional contact measurement method of extensometer can no longer meet the fast and safe construction requirements of modern long tunnels. Therefore, a non-contact measurement method that is fast, simple, and less affected by tunnel construction—total station side-to-side measurement method has been gradually introduced into the tunnel clearance and convergence monitoring measurement. However, there are relatively few studies on the measurement accuracy of this measurement method at present, and there is no clear conclusion as a basis for on-site measurement to improve measurement accuracy.

三、发明内容：3. Contents of the invention:

为了解决上述背景技术中的不足之处，本发明提供一种提高全站仪对边测量隧道净空收敛精度的方法，其采用全站仪对边量测法，基于两车道、三车道和四车道公路隧道实际断面大小，及现场净空收敛量测实际情况，通过选择合理的全站仪架设位置，提高量测精度。In order to solve the deficiencies in the above-mentioned background technology, the present invention provides a method for improving the convergence accuracy of total station measuring tunnel clearance on the opposite side. The actual section size of the highway tunnel and the actual situation of the on-site clearance convergence measurement can improve the measurement accuracy by selecting a reasonable erection position of the total station.

为实现上述目的，本发明采用的技术方案为：一种提高全站仪对边测量隧道净空收敛精度的方法，其特征在于：所述的方法步骤为：In order to achieve the above object, the technical solution adopted in the present invention is: a method for improving the convergence accuracy of total station measuring tunnel headroom on the opposite side, characterized in that: the method steps are:

首先，将两监测点左右对称布设在监测断面最大开挖线处，并进行保护，避免监测点在隧道施工中被影响破坏；First of all, the two monitoring points are symmetrically arranged at the maximum excavation line of the monitoring section and protected to avoid the monitoring points being affected and damaged during the tunnel construction;

然后，选择合理位置架设全站仪：Then, choose a reasonable location to set up the total station:

两车道公路隧道，将全站仪架设在距隧道监测断面40～60m，距隧道中心线5.25m的范围之内；For two-lane highway tunnels, the total station should be set up within the range of 40-60m from the tunnel monitoring section and 5.25m from the center line of the tunnel;

三车道公路隧道，将全站仪架设在距隧道监测断面40～50m，距隧道中心线2.13m范围之内；或将全站仪架设在距监测断面50～70m，距隧道中心线6.38m范围之内；For three-lane road tunnels, install the total station within 40-50m from the tunnel monitoring section and 2.13m from the tunnel centerline; or install the total station 50-70m from the monitoring section and 6.38m from the tunnel centerline within;

四车道公路隧道，将全站仪架设在距监测断面50～60m，距隧道中心线2.63m范围之内；或将全站仪架设在距监测断面60～70m，距隧道中心线5.25m范围之内；For four-lane road tunnels, install the total station within 50-60m from the monitoring section and within 2.63m from the tunnel centerline; or install the total station within 60-70m from the monitoring section and 5.25m from the tunnel centerline Inside;

在满足以上条件的情况下，若现场条件允许，尽量将全站仪架设在靠近隧道中心线处；In the case of meeting the above conditions, if the site conditions permit, try to set up the total station near the center line of the tunnel;

最后，利用全站仪对边测量功能完成量测数据读取，并在每一次量测完成后恢复测点保护。如此，分别将施工不同阶段的净空收敛量测数据与初始测量值相减，计算得到监测断面净空收敛结果。Finally, use the side-to-side measurement function of the total station to complete the measurement data reading, and restore the measurement point protection after each measurement is completed. In this way, the clearance convergence measurement data at different stages of construction are subtracted from the initial measurement value, and the clearance convergence results of the monitoring section are calculated.

与现有技术相比，本发明具有的优点和效果如下：该方法主要从全站仪架设位置出发，对最优位置参数进行了量化，结果直观，易执行；针对两车道、三车道、四车道公路隧道分别给出了相应的全站仪最优位置参数，结果全面，更有利于成果推广；该方法严格依照对边测量原理及误差传播定律，同时结合现场隧道净空收敛量测实际情况，可靠度高。Compared with the prior art, the present invention has the following advantages and effects: the method mainly starts from the erection position of the total station, quantifies the optimal position parameters, and the result is intuitive and easy to implement; for two-lane, three-lane, four-lane The corresponding optimal position parameters of the total station are given in the lane highway tunnel, and the results are comprehensive, which is more conducive to the promotion of the results; this method is strictly in accordance with the principle of opposite-side measurement and the law of error propagation, and combined with the actual situation of the on-site tunnel clearance convergence measurement, High reliability.

四、附图说明：4. Description of drawings:

图1为全站仪对边测量隧道净空收敛原理图；Figure 1 is a schematic diagram of the convergence of the total station's side-to-side measurement of the tunnel clearance;

图2为量测平面投影计算示意图；Fig. 2 is a schematic diagram of measurement plane projection calculation;

图3为隧道净空收敛测站位置布置图；Figure 3 is the location layout of the tunnel clearance convergence measuring station;

图4为反射膜片粘贴；Figure 4 is the pasting of the reflective film;

图5为测点保护；Figure 5 is the measuring point protection;

图6为YK110+878断面最大开挖线收敛时态曲线；Figure 6 is the time-state curve of the maximum excavation line convergence of the YK110+878 section;

图7为YK110+870断面最大开挖线收敛时态曲线；Figure 7 is the time-state curve of the maximum excavation line convergence of the YK110+870 section;

图8为YK110+861断面最大开挖线水平收敛时态曲线。Figure 8 is the temporal curve of the horizontal convergence of the maximum excavation line of the YK110+861 section.

五、具体实施方式：5. Specific implementation methods:

下面结合附图和具体实施方式对本发明进行详细说明：The present invention is described in detail below in conjunction with accompanying drawing and specific embodiment:

首先，进行监测断面测点的埋设和保护。Firstly, the embedding and protection of the measuring points of the monitoring section shall be carried out.

在隧道最大开挖线左右壁面对称布设两个监测点，即图1所示的P、A两点。测点埋设时，首先将预先加工好的钢板作为反射膜片底座，焊接在靠近掌子面第一榀型钢拱架上P、A两点对应位置。然后，将反射膜片粘贴在固定完成的钢板上，并尽量保证两反射膜片中心点处于同一水平线上。在喷射混凝土前，需将塑料袋或土工布等物件缠绕在测点上加以保护，避免反射膜片被污染、破坏。喷射混凝土作业完成后，解开保护物件，立即进行初读数的读取。在初始测量以及之后的每一次测量完成后，均须及时恢复测点保护，以免隧道施工期间反射膜片表面被污染，影响测量数据的准确性。另外，在整个监测过程中，应加强与相关部门的协调工作，避免因隧道施工造成测点的位置偏移或破坏。Two monitoring points are arranged symmetrically on the left and right walls of the tunnel's largest excavation line, namely P and A as shown in Figure 1. When the measuring point is buried, firstly, the pre-processed steel plate is used as the base of the reflective diaphragm, which is welded to the corresponding positions of P and A on the first steel arch near the face of the tunnel. Then, paste the reflective film on the fixed steel plate, and try to ensure that the center points of the two reflective films are on the same horizontal line. Before spraying concrete, it is necessary to wrap plastic bags or geotextiles and other objects on the measuring point for protection, so as to prevent the reflective membrane from being polluted and damaged. After the shotcrete operation is completed, untie the protective object and take the initial reading immediately. After the initial measurement and each subsequent measurement, the protection of the measuring point must be restored in time to prevent the surface of the reflective film from being polluted during tunnel construction and affecting the accuracy of the measurement data. In addition, during the entire monitoring process, coordination with relevant departments should be strengthened to avoid displacement or damage of measuring points due to tunnel construction.

然后，建立全站仪对边测量隧道净空收敛精度计算模型，并进行分析。Then, the calculation model of the convergence accuracy of the total station measuring the tunnel clearance on the opposite side is established and analyzed.

一般测量精度由测量中误差进行评价。由图1可得，P、A两点间的高差h_PA，水平间距D_PA和斜距S_PA的计算公式：The general measurement accuracy is evaluated by the error in the measurement. It can be obtained from Figure 1 that the calculation formulas for the height difference h _PA between two points P and A, the horizontal distance D _PA and the slope distance S _PA are as follows:

h_PA＝h_P-h_A＝S_Psinα_P-S_Asinα_A(1)h _PA ＝h _P -h _A ＝S _P sinα _P -S _A sinα _A (1)

DD. PP AA == SS PP 22 coscos 22 αα PP ++ SS AA 22 coscos 22 αα AA -- 22 SS PP SS AA cosαcosα PP cosαcosα AA cc oo sthe s ββ -- -- -- (( 22 ))

SS PP AA == hh PP AA 22 ++ DD. PP AA 22 -- -- -- (( 33 ))

其中，S_P、S_A分别为OP、OA斜距，α_P、α_A分别为OP、OA测量竖直角，β为OP、OA之间水平角。Among them, S _P and S _A are the slant distances of OP and OA respectively, α _P and α _A are the measured vertical angles of OP and OA respectively, and β is the horizontal angle between OP and OA.

不考虑地球曲率和大气折光的影响，对式(3)进行全微分，并依据误差传播定律，得到隧道净空收敛中误差计算公式：Without considering the influence of the curvature of the earth and atmospheric refraction, formula (3) is fully differentiated, and according to the law of error propagation, the error calculation formula in the convergence of tunnel clearance is obtained:

mm SS PP AA 22 == 11 SS PP AA 22 {{ [[ -- hh PP AA tgαtgα PP ++ (( DD. PP -- DD. AA coscos ββ )) ]] 22 coscos 22 αα PP mm SS PP 22 ++ [[ hh PP AA tgαtgα AA ++ (( DD. AA -- DD. PP coscos ββ )) ]] 22 coscos 22 αα AA mm SS AA 22 ++ 11 ρρ 22 [[ -- hh PP AA ctgαctgα PP -- (( DD. PP -- DD. AA coscos ββ )) ]] 22 SS PP 22 sinsin 22 αα PP mm αα PP 22 ++ 11 ρρ 22 [[ hh PP AA ctgαctgα AA -- (( DD. AA -- DD. PP coscos ββ )) ]] 22 SS AA 22 sinsin 22 αα AA mm αα AA 22 ++ 11 ρρ 22 (( DD. PP DD. AA sinsin ββ )) 22 mm ββ 22 }} -- -- -- (( 44 ))

式中，ρ＝206265″，和m_β分别为S_P、S_A、α_P、α_A和β的测量中误差，D_P＝S_Pcosα_P、D_A＝S_Acosα_A，D_P、D_A分别为OP和OA水平距离。In the formula, ρ=206265", and m _β are the measurement errors of S _P , S _A , α _P , α _A and β respectively, D _P ＝ S _P cos α _P , D _A ＝ S _A cos α _A , D _P , DA are the levels of OP and _OA respectively distance.

根据图2全站仪对边测量隧道净空收敛水平投影图中D_P、D_A与D_PA之间的三角函数关系，对式(4)进行转化，并假定D_PA＝S_PA及测角中误差 m a P = m a A = m a , 得到：According to the trigonometric function relationship between D _P , D _A and D _PA in the horizontal projection diagram of tunnel clearance measured by the total station on the opposite side in Fig. 2, formula (4) is transformed, and it is assumed that D _PA = S _PA and error m a P = m a A = m a , get:

mm SS PP AA 22 == coscos 22 ββ PP (( coscos 22 αα PP mm SS PP 22 ++ 11 ρρ 22 SS PP 22 sinsin 22 αα PP mm αα 22 )) ++ coscos 22 ββ AA (( coscos 22 αα AA mm SS AA 22 ++ 11 ρρ 22 SS AA 22 sinsin 22 αα AA mm αα 22 )) 11 ρρ 22 (( DD. PP AA ctgβctgβ PP ++ ctgβctgβ AA )) 22 mm ββ 22 -- -- -- (( 55 ))

以此为基础，结合现场净空收敛量测实际情况，计算分析不同跨度隧道全站仪不同架设位置时净空收敛测量精度。Based on this, combined with the actual situation of on-site headroom convergence measurement, the accuracy of headroom convergence measurement at different erection positions of total stations for tunnels with different spans is calculated and analyzed.

其次，选择全站仪合理架设位置。Secondly, choose a reasonable erection location for the total station.

根据不同跨度隧道对边测量净空收敛精度分析结果，选择合理的全站仪架设位置，具体如表1所示。在此位置范围内，若现场条件允许，尽量使全站仪架设位置靠近隧道中心线。According to the analysis results of the convergence accuracy of the clearance measurement on the opposite sides of tunnels with different spans, a reasonable total station erection position is selected, as shown in Table 1. Within the scope of this position, if the site conditions permit, try to make the erection position of the total station close to the center line of the tunnel.

最后，利用全站仪对边测量功能完成量测数据读取，计算得到监测断面相对于初始量测值的净空收敛结果。Finally, the measurement data reading is completed by using the side-to-side measurement function of the total station, and the clearance convergence result of the monitoring section relative to the initial measurement value is calculated.

在全站仪架设完成后，选用仪器自带的对边测量功能，分别照准点P和点A的反射膜片中心点，便可在屏幕中直接读取P、A两点斜距S_PA。本质上，该值的得出是利用全站仪自身内置程序，通过直接测量全站仪中心与测点之间的斜距、竖直角，以及两测点之间的水平角，按式(1)～(3)计算得到。在每一次量测完成后，均须恢复监测点的保护。如此，根据施工不同阶段量测得到的S_PA值，分别将其与初始量测值相减，计算得到隧道监测断面净空收敛结果。After the installation of the total station is completed, select the side-to-side measurement function that comes with the instrument, aim at the center of the reflective diaphragm at point P and point A respectively, and then read the slope distance S _PA of points P and A directly on the screen. In essence, this value is obtained by using the built-in program of the total station itself, by directly measuring the slant distance between the center of the total station and the measuring point, the vertical angle, and the horizontal angle between the two measuring points, according to the formula ( 1) ~ (3) calculated. After each measurement is completed, the protection of the monitoring point shall be restored. In this way, according to the _SPA values measured at different stages of construction, they are subtracted from the initial measured values, and the convergence results of the clearance of the tunnel monitoring section are calculated.

实施例：Example:

以陕西省神木至府谷高速公路大断面三车道黄土公路隧道最大开挖线水平收敛量测为例，进行详细介绍。Taking the horizontal convergence measurement of the maximum excavation line of the large-section three-lane loess road tunnel of the Shenmu-Fugu Expressway in Shaanxi Province as an example, a detailed introduction is made.

测点埋设时，先将预先加工好的钢板作为反射膜片底座，焊接在隧道开挖后靠近掌子面第一榀型钢拱架上的P、A两点对应位置(如图1所示)。P、A点分别位于监测断面左右侧最大开挖线处。然后，将反射膜片粘贴在固定完成的钢板上，如图4所示。在反射膜片粘贴时，应尽量保证两反射膜片中心点处于同一水平线上。在反射膜片粘贴完成后，将土工布包裹在测点上，并用胶带进行缠绕捆扎(如图5所示)，予以保护，避免反射膜片在之后喷射混凝土时被污染、破坏。When the measuring point is buried, the pre-processed steel plate is used as the base of the reflective diaphragm, and welded to the corresponding positions of P and A on the first steel arch near the tunnel face after excavation (as shown in Figure 1) . Points P and A are respectively located at the maximum excavation line on the left and right sides of the monitoring section. Then, paste the reflective film on the fixed steel plate, as shown in Figure 4. When pasting the reflective film, try to ensure that the center points of the two reflective films are on the same horizontal line. After the reflective diaphragm is pasted, wrap the geotextile on the measuring point and wrap it with adhesive tape (as shown in Figure 5) to protect it and prevent the reflective diaphragm from being polluted and damaged when the concrete is sprayed later.

根据所依托的大断面三车道公路隧道的实际断面大小，取断面最大开挖线水平收敛测线长度S_PA(假定S_PA＝D_PA)为17m，与路面的垂直高度为2m。因全站仪架设高度通常为1.2～1.5m，考虑竖直角的影响，取全站仪距最大开挖线水平测线垂直高度为1m。在测量过程中，由于对边量测测角β为半测回角值，因此取m_β＝m_半角＝±2″。全站仪测量精度为“m_s＝2+2ppm，m_α＝1″”。基于以上，通过全站仪对边测量精度计算模型(式5)，计算得到不同全站仪位置设置下断面最大开挖线水平测线测量中误差。由于P、A两点关于隧道中心线左右对称，因此仅考虑将全站仪布设在隧道中心线一侧进行精度计算分析，如图3所示。其中，h为全站仪架设位置距量测断面的水平距离。最后计算结果如表2所示。According to the actual section size of the large-section three-lane highway tunnel, the maximum excavation line horizontal convergence measuring line length S _PA of the section (assuming S _PA = D _PA ) is taken as 17m, and the vertical height to the road surface is 2m. Since the erection height of the total station is usually 1.2-1.5m, considering the influence of the vertical angle, the vertical height from the total station to the horizontal measuring line of the maximum excavation line is taken as 1m. During the measurement process, since the angle β measured on the opposite side is the half-measured return angle value, m _β =m _half -angle=±2". The measurement accuracy of the total station is "m _s =2+2ppm, m _α =1 "". Based on the above, the error in the measurement of the horizontal survey line of the maximum excavation line of the lower section under different total station position settings is calculated through the calculation model of the measurement accuracy of the total station (equation 5). Since the two points P and A are left-right symmetrical about the center line of the tunnel, only the total station is considered to be placed on one side of the center line of the tunnel for accuracy calculation and analysis, as shown in Figure 3. Among them, h is the horizontal distance between the erection position of the total station and the measurement section. The final calculation results are shown in Table 2.

基于表2的计算结果，得出：在三车道公路隧道最大开挖线水平收敛量测时，将全站仪架设在距隧道监测断面40～50m，距隧道中心线2.125m范围以内；或将全站仪架设在距隧道监测断面50～70m，距隧道中心线6.375m范围以内，测量中误差相对于其它位置设置较低，均在0.70以下，且全站仪越靠近隧道中心线，测量精度越高。Based on the calculation results in Table 2, it is concluded that when measuring the horizontal convergence of the maximum excavation line of a three-lane highway tunnel, the total station should be set up within 40-50m from the tunnel monitoring section and within 2.125m from the tunnel centerline; or The total station is set up at a distance of 50-70m from the tunnel monitoring section and within 6.375m from the tunnel centerline. Compared with other locations, the measurement error is lower, all below 0.70, and the closer the total station is to the tunnel centerline, the better the measurement accuracy. higher.

因此，在喷射混凝土施工完成后，及时取下测点保护物件，按表1要求完成全站仪架设(在现场条件允许情况下，尽量使全站仪架设位置靠近隧道中心线)，读取量测数据，作为隧道净空收敛监测的初始读数。量测时，首先选择全站仪自带的对边测量功能，然后分别照准点P和点A的反射膜片中心点，如此便可在全站仪屏幕上直接读取PA斜距S_PA，完成初始测量。Therefore, after the shotcrete construction is completed, remove the protective objects at the measuring points in time, and complete the erection of the total station according to the requirements in Table 1 (if the site conditions permit, try to make the erection position of the total station close to the center line of the tunnel), the reading volume The measured data is used as the initial reading for tunnel clearance convergence monitoring. When measuring, first select the side-to-side measurement function that comes with the total station, and then aim at the center of the reflective diaphragm at point P and point A respectively, so that the PA slope distance S _PA can be directly read on the screen of the total station, Complete initial measurements.

在初始测量以及之后每一次测量完成后，均及时恢复测点的保护，避免隧道施工中反射膜片表面被污染，影响测量数据的准确性。同时，在整个监测过程中，加强与相关部门的协调工作，避免因隧道施工造成测点的位置偏移或破坏。After the initial measurement and each subsequent measurement, the protection of the measuring point is restored in time to avoid contamination of the reflective membrane surface during tunnel construction and affect the accuracy of the measurement data. At the same time, during the whole monitoring process, the coordination with relevant departments should be strengthened to avoid position shift or damage of measuring points caused by tunnel construction.

如此，根据施工不同阶段测量得到的S_PA值，分别将其与初始测量值相减，计算得出隧道监测断面最大开挖线相对于初始量测值的水平收敛。监测结果如图6‐8所示。In this way, according to the S _PA values measured at different stages of construction, they are subtracted from the initial measured values, and the horizontal convergence of the maximum excavation line of the tunnel monitoring section relative to the initial measured values is calculated. The monitoring results are shown in Figure 6‐8.

由图6‐8可知，该对边测量方法测量结果与坐标测量相比精度更高，更稳定；测量结果变化规律与收敛计测量基本一致。因此，该方法不仅弥补了收敛计测量前期净空收敛数据缺失的缺点，而且很好地保证了测量精度，测量结果理想。It can be seen from Fig. 6-8 that the measurement result of this opposite-side measurement method is higher in precision and more stable than that of coordinate measurement; the change rule of the measurement result is basically consistent with that of the convergent meter measurement. Therefore, this method not only makes up for the shortcoming of the lack of headroom convergence data in the early stage of the convergence meter measurement, but also ensures the measurement accuracy well, and the measurement results are ideal.

表1两车道、三车道和四车道公路隧道全站仪架设位置设置Table 1 Erection position setting of total station for two-lane, three-lane and four-lane highway tunnels

表2三车道公路隧道全站仪位置变化最大开挖线水平测线对边测量中误差Table 2 The maximum position change of the total station in the three-lane road tunnel The error in the side-to-side measurement of the horizontal survey line of the excavation line

1. improve a method for total powerstation Opposite side survey tunnel clearance convergence precision, it is characterized in that: described method step is:

First, be laid in the maximum excavatoin line place of monitoring section by symmetrical for two monitoring points, and protect, avoid monitoring point to be affected destruction in constructing tunnel;

Then, rational position erection total powerstation is selected:

Two lane vural roads tunnel, is erected at apart from tunnel monitoring section 40 ~ 60m by total powerstation, within the scope of distance tunnel center line 5.25m;

Three-Lane Highway Tunnel, is erected at apart from tunnel monitoring section 40 ~ 50m, within tunnel center line 2.13m scope by total powerstation; Or total powerstation is erected at apart from monitoring section 50 ~ 70m, within tunnel center line 6.38m scope;

Four lane road tunnel, is erected at apart from monitoring section 50 ~ 60m, within tunnel center line 2.63m scope by total powerstation; Or total powerstation is erected at apart from monitoring section 60 ~ 70m, within tunnel center line 5.25m scope;

When meeting above condition, if field condition allows, total powerstation is erected near tunnel centerline as far as possible;

Finally, utilize total powerstation Opposite side survey function to complete measurement digital independent, and after having measured each time, recover measuring point protection.So, respectively the clearance convergence metric data of construction different phase and initial measurement are subtracted each other, calculate monitoring section clearance convergence result.