地铁基坑维护墙(桩)顶水平位移监测方法的比较

地铁基坑维护墙(桩)顶水平位移监测方法的比较 地铁基坑维护墙(桩)顶水平位移监测方法的比较 测绘工程部 段绪稳 摘要:介绍了地铁基坑维护墙(桩)顶水平位移监测的常用方法及其优缺点，通过比较各种方法在地铁基坑监测中的适用性，来探讨地铁基坑特定环境下适合的监测方法。 关键词:地铁基坑 监测 水平位移 方法 1、前言 在城市地铁车站建设施工中，为确保车站基坑的开挖及周边建、构筑物的安全，必须进行安全监测。基坑维护墙(桩)顶水平位移(以下简称“水平位移”)监测就是其中非常重要的一个项目。在地铁基坑特定的环境下，选择何种监测方法才能方便、快捷的获取监测数据，是水平位移监测要解决的首要问 题 快递公司问题件快递公司问题件货款处理关于圆的周长面积重点题型关于解方程组的题及答案关于南海问题 。笔者通过对各种水平位移监测方法的优、缺点进行比较、分析，来探讨适合于地铁基坑水平位移监测的方法。 2、水平位移监测的方法 水平位移常用的监测方法主要有视准线法、单站改正法、极坐标法、前方交会法、后方交会法以及导线测量等等。 2.1、视准线法 视准线法按其作业方法和所使用的工具的不同，又可分为“测小角法”和“活动觇牌法”。 2.1.1 测小角法 测小角法就是如右图所示，先确定一条A、B已知观测墩，P、P1 点为待求坐标点P1平行于基坑的基准线AB，然后测定基准线Pβ'BAβ,与基准点到监测点视线之间的微小角度 S (建筑物变形监测 规范 编程规范下载gsp规范下载钢格栅规范下载警徽规范下载建设厅规范下载 要求不超过30″)， design of urban bridge (CJJ 11-2011), General specification for design of highway bridges and culverts (JTG D60-2004) code for design of reinforced concrete and prestressed concrete Highway (JTG D62-2004) of the highway bridge design specifications for masonry (JTG D61-2005) code for design of highway bridge and culvert 1, course name: car air conditioning repair Mo Zhen, Editor 2, course code: 3, credits/units: 160 hours 4, major: automobile maintenance and testing specialty second nature and task 1, course, course: this course is a professional course of automobile maintenance and testing specialty. 2, task: the teaching of this module is to the automotive air conditioning repair class teaching in conjunction with training courses, small-class teaching and practical training in the teaching process, theory for sufficient degree, with a focus on fostering students ' practical skills. Through this module students learn can master the skills of maintenance of auto air conditioning; theory with practice, testing, analysis, judgement and skill to help troubleshoot auto air conditioning in common, which reflect the automobile application technologySummary of excavation of Foundation pit engineering below refers to the surface of a supporting system of underground space and its supporting. To ensure 以及基准点与监测点之间的距离;通过每两次观测的角度变化来求得监测S,PP点的偏离值。其计算公式如下: LP ,PL,,SPP , 测小角法的观测误差主要由测角引起，其由距离引起的误差非常小，可以忽略不计。因此，其边长只需初始测量一次即可，从而大大减少了工作量。另外，由于测角的精度可以通过增加测回数来提升，所以测小角法可以得到比较高的精度。 测小角法的缺点有:1、只能得到垂直于基准线方向的位移，所以只适合于形状规整的基坑;2、为了确保位移测量的精度，监测点的距离不能太长，对于边长较长的基坑不适用;3、监测点与基准点之间的微小角度要求对监测点的布设提出了较高要求。 2.1.2 活动觇牌法 活动觇牌法与测小角法原理相似，不同的是在监测点处不 是安置固定觇牌，而是利用一种精密的附有读数装置的活动觇 牌(如右图所示)来直接测定偏离值。测量时通过调节觇牌的 测微装置，使觇牌上的照准标志移到基准线上，再在读数装置 上读出偏离值。 活动觇牌法可以直接读出偏离值，省去了数据计算的步 骤，减少了内业工作量。由于其原理跟测小角法相似，所以也 有着测小角法的不足之处。此外，该方法至少需要两个人相互 配合操作，才能实施，增加了操作难度和工作量。 2.2、单站改正法 单站改正法是一种将视准线小角法与监测点设站法结合使用的方法，这种方法只需仪器一次设站，加改正来完成所有监 测点位移量的测算。如图所示: 在施工影响之外的坚固建筑物上设了两 个标志 A、B。每次监测时，先要测量?APB 角的变化量，求得 P 点的横向位移量Δp， design of urban bridge (CJJ 11-2011), General specification for design of highway bridges and culverts (JTG D60-2004) code for design of reinforced concrete and prestressed concrete Highway (JTG D62-2004) of the highway bridge design specifications for masonry (JTG D61-2005) code for design of highway bridge and culvert 1, course name: car air conditioning repair Mo Zhen, Editor 2, course code: 3, credits/units: 160 hours 4, major: automobile maintenance and testing specialty second nature and task 1, course, course: this course is a professional course of automobile maintenance and testing specialty. 2, task: the teaching of this module is to the automotive air conditioning repair class teaching in conjunction with training courses, small-class teaching and practical training in the teaching process, theory for sufficient degree, with a focus on fostering students ' practical skills. Through this module students learn can master the skills of maintenance of auto air conditioning; theory with practice, testing, analysis, judgement and skill to help troubleshoot auto air conditioning in common, which reflect the automobile application technologySummary of excavation of Foundation pit engineering below refers to the surface of a supporting system of underground space and its supporting. To ensure 再测量?AP i 角的变化量，进而求得监测点 i 的横向位移量Δi 。其计算公式如下: 单站改正法是一种特殊的测小角法，由于这种方法可以在监测点处设站，所以相对测小角法而言其观测范围扩大了一倍，在一定程度上解决了测小角法距离不能太长的问题。然而由于每次都必须观测测站点角度的变化，对测站点进行改正，增加了内、外业的工作量。另外，此方法必须在监测点上建立强制对中观测墩才能进行观测，增加了布点难度。 2.3、极坐标法 极坐标法是利用数学中的极坐标原理，以两个已知点为坐标轴，以其中一个点为极点建立极坐标系，测定观测点到极点的距离，以及观测点与极点连线和两个已知点连线的夹角从而来计算观测点坐标的方法。如图: 测定待求点C坐标时，先计算已知点A、BA、B已知点，C、C'A点为待求坐标点的方位角: CYY,,ABC',,arctan()，180/,BAβ'XX, SABβS'测定角度β和边长BC，则 BC的方位角: ,,,，,BBCBA X,X，S，cos(,)C点的坐标: CBBC Y,Y，S，sin(,) CBBC 由于极坐标是测定监测点的坐标，所以可以得到监测点在任意方向上的变化。其次，极坐标法设站灵活，只要已知一个点的坐标和一个后视方向就可以在design of urban bridge (CJJ 11-2011), General specification for design of highway bridges and culverts (JTG D60-2004) code for design of reinforced concrete and prestressed concrete Highway (JTG D62-2004) of the highway bridge design specifications for masonry (JTG D61-2005) code for design of highway bridge and culvert 1, course name: car air conditioning repair Mo Zhen, Editor 2, course code: 3, credits/units: 160 hours 4, major: automobile maintenance and testing specialty second nature and task 1, course, course: this course is a professional course of automobile maintenance and testing specialty. 2, task: the teaching of this module is to the automotive air conditioning repair class teaching in conjunction with training courses, small-class teaching and practical training in the teaching process, theory for sufficient degree, with a focus on fostering students ' practical skills. Through this module students learn can master the skills of maintenance of auto air conditioning; theory with practice, testing, analysis, judgement and skill to help troubleshoot auto air conditioning in common, which reflect the automobile application technologySummary of excavation of Foundation pit engineering below refers to the surface of a supporting system of underground space and its supporting. To ensure 该点上设站、测量。因此，极坐标法可以有效的避开遮挡，顺利地采集监测数据。另外，极坐标可以一次测定多个方向的监测点，使得工作效率大大提高。以前由于极坐标法对仪器精度的要求较高，使其应用受到限制，使用较少;然而现在随着高精度仪器的普及，该方法使用的也越来越多。 2.4、前方交会法 测角前方交会法原理如右图所示，用经纬仪分 别在已知点A和B上测出角α和角β，可根据下 式计算待定点P的坐标: 前方交会法一般是在周边建筑物顶上布设强制对中观测墩，在其上设站观测。所以其视角开阔，基本上能观测到基坑内的所有点。然而，它至少须在两个观测墩上设站测量，观测量较大。并且，两个观测墩之间的转站通常是在两栋建筑物之间转，非常费时费事。另一方面，前方交会对于图形条件的要求高，从而限制了其大范围的使用，一般只对少数点使用。在地铁基坑监测中，前方交会一般用于工作基点的稳定性检查。 2.5、后方交会法 如右图所示，后方交会就是在未知点P处 设站，观测三个已知点A、B、C之间的夹角α、 β、γ，则可计算P点坐标: PX，PX，PXAABBCCX,pP，P，P ABC PY，PY，PY AABBCCY,pP，P，PABC 111P,P,P,其中: ABCctgA,ctg,ctgB,ctg,ctgC,ctg, design of urban bridge (CJJ 11-2011), General specification for design of highway bridges and culverts (JTG D60-2004) code for design of reinforced concrete and prestressed concrete Highway (JTG D62-2004) of the highway bridge design specifications for masonry (JTG D61-2005) code for design of highway bridge and culvert 1, course name: car air conditioning repair Mo Zhen, Editor 2, course code: 3, credits/units: 160 hours 4, major: automobile maintenance and testing specialty second nature and task 1, course, course: this course is a professional course of automobile maintenance and testing specialty. 2, task: the teaching of this module is to the automotive air conditioning repair class teaching in conjunction with training courses, small-class teaching and practical training in the teaching process, theory for sufficient degree, with a focus on fostering students ' practical skills. Through this module students learn can master the skills of maintenance of auto air conditioning; theory with practice, testing, analysis, judgement and skill to help troubleshoot auto air conditioning in common, which reflect the automobile application technologySummary of excavation of Foundation pit engineering below refers to the surface of a supporting system of underground space and its supporting. To ensure 后方交会法一般也用于工作基点墩的稳定性检查。由于后方交会只要在未知点上设站就可以，所以较前方交会其工作量较少。此外，后方交会可以利用基坑周边固定的房角做观测目标，而不必做强制对中观测墩，方便易行，适用范围更广。 2.6、导线测量法 导线测量法就是通过从基坑外稳定的基点向基坑内观测点做闭合或者附和导线来测定观测点的变化的方法。 导线测量最大的优势是基点和观测点之间不必通视，但是其观测的工作量大，操作起来比较麻烦，精度也不高，所以使用的较少。该方法一般是在基坑周边建筑物特别密集的时候，用于工作基点的稳定性的检查。 3、水平位移监测方法的比较 在地铁基坑水平位移监测当中，视准线法、单站改正法和极坐标法是常用的方法。 在地铁基坑的施工中，其冠梁上经常会摆放材料，停放施工机械，且还是人行通道，工作人员常在上面走动、工作。所以冠梁上的视线经常是受阻而不通视的。在这种条件下，视准线法和单站改正法实施起来非常困难。相对而言，极坐标法设站灵活，当采取基坑对角定向时，可以避开绝大部分的遮挡情况。并且，有时候当一个方向被阻，换个设站点，就可以观测到了，使得监测能够顺利进行。当使用先进的仪器，如莱卡TCA2003，极坐标法可以实现自动观测，减少人为的观测误差，大大减轻了工作强度，提高了工作效率。特别是基坑施工发生险情需要连续观测时，该方法有迅速获得监测成果的优势。 前方交会法、后方交会法以及导线测量法在地铁基坑水平位移中一般用于工作基点的检查。相对前方交会来讲，后方交会可以根据场地条件选择房角等自然标志来进行测量，无需建立强制对中观测墩，简单易行，比较实用。导线测量其操作比较繁琐，精度不高，平常较少使用。一般在场地条件限制，前、后方交会等方法都无法使用时才采用。 design of urban bridge (CJJ 11-2011), General specification for design of highway bridges and culverts (JTG D60-2004) code for design of reinforced concrete and prestressed concrete Highway (JTG D62-2004) of the highway bridge design specifications for masonry (JTG D61-2005) code for design of highway bridge and culvert 1, course name: car air conditioning repair Mo Zhen, Editor 2, course code: 3, credits/units: 160 hours 4, major: automobile maintenance and testing specialty second nature and task 1, course, course: this course is a professional course of automobile maintenance and testing specialty. 2, task: the teaching of this module is to the automotive air conditioning repair class teaching in conjunction with training courses, small-class teaching and practical training in the teaching process, theory for sufficient degree, with a focus on fostering students ' practical skills. Through this module students learn can master the skills of maintenance of auto air conditioning; theory with practice, testing, analysis, judgement and skill to help troubleshoot auto air conditioning in common, which reflect the automobile application technologySummary of excavation of Foundation pit engineering below refers to the surface of a supporting system of underground space and its supporting. To ensure 4.结语 地地铁基坑施工现场环境复杂，遮挡情况严重，限制了许多监测方法的使用。极坐标法方便灵活，能较好的避开各种遮挡，且工作效率高，适合于各种形状的基坑，是地铁基坑水平位移监测比较合适的方法。此外，后方交会法方便易行，可以根据现场的情况选择周边建筑物房角进行观测，而不必布设观测墩，适用范围广，是水平位移监测基准点检查的好方法。 参考文献: [1] 朱建军，贺跃光等 变形测量的理论与方法[M]，长沙:中南大学出版社，2004.2 [2] 中华人民共和国国家标准《建筑基坑工程监测技术规范》[S](GB50497-2009). [3] 中华人民共和国行业标准《建筑变形测量规范》[S] (JGJ7-2008). [5] 寇刚，姚连壁.基坑水平位移监测方法的探讨[J]，地矿测绘，2002，18(4). [4] 李涛，任建喜，毛巨省.城市地铁车站深基坑施工监测 方案 气瓶 现场处置方案 .pdf气瓶 现场处置方案 .doc见习基地管理方案.doc关于群访事件的化解方案建筑工地扬尘治理专项方案下载 设计 领导形象设计圆作业设计ao工艺污水处理厂设计附属工程施工组织设计清扫机器人结构设计 研究[J]，地下空间与工程学报，2007年12月. design of urban bridge (CJJ 11-2011), General specification for design of highway bridges and culverts (JTG D60-2004) code for design of reinforced concrete and prestressed concrete Highway (JTG D62-2004) of the highway bridge design specifications for masonry (JTG D61-2005) code for design of highway bridge and culvert 1, course name: car air conditioning repair Mo Zhen, Editor 2, course code: 3, credits/units: 160 hours 4, major: automobile maintenance and testing specialty second nature and task 1, course, course: this course is a professional course of automobile maintenance and testing specialty. 2, task: the teaching of this module is to the automotive air conditioning repair class teaching in conjunction with training courses, small-class teaching and practical training in the teaching process, theory for sufficient degree, with a focus on fostering students ' practical skills. Through this module students learn can master the skills of maintenance of auto air conditioning; theory with practice, testing, analysis, judgement and skill to help troubleshoot auto air conditioning in common, which reflect the automobile application technologySummary of excavation of Foundation pit engineering below refers to the surface of a supporting system of underground space and its supporting. To ensure