路基的施工放样

内蒙古交通职业技术学院毕业设计（论文）1目录摘要·····································································································1前言·····································································································2第一章施工放样的基本方法········································································31.1已知距离的放样··················································································31.2已知高程的放样··················································································41.3已知点的放样·····················································································5第二章中线放样·······················································································8第三章路基的施工放样··············································································93.1路基横断面施工放样············································································93.2路基边桩放样的一般要求····································································103.3路基横断面的放样方法·······································································103.4路基边坡的放样················································································133.5路基施工阶段各层次的抄平方法···························································143.6线段路基顶面的抄平··········································································153.7线段路基顶面的抄平··········································································17第四章路面的施工放样············································································184.1路槽的放样······················································································184.2路面放样·························································································194.3路拱放样·························································································204.4造物施工放样···················································································214.5挡土墙施工放样················································································234.6沿线取土坑、弃土堆占地面积及土方量计算···········································254.7占地面积的测算················································································254.8土方量测算······················································································26结论···································································································28致谢···································································································29参考文献································································································30内蒙古交通职业技术学院毕业设计（论文）-1-1摘要测量的工作包括内业和外业，本文主要阐述外业的内容，即施工放线。测量放样工作应遵循从整体到局部的原则，先进行控制测量，再进行细部放样测量。通过控制测量，建立起平面控制点和高程控制点与工程构造物特征点之间的平面位置和高程的几何联系。但其实在一线施工的人员都知道一个潜规则，那就是搞测量的师傅们是不会轻易得告诉你施工测量中的所用的公式，因为那是他们的赚钱法宝，说出来他就没得活干了，以至于在工地的测量施工人员很少能彻底搞清楚施工放线中的来龙去脉，为了保证工程质量及杜绝工程上出现这类恶略现象特出此文.关键词：公路工程；施工放样；潜规则内蒙古交通职业技术学院毕业设计（论文）-2-2前言工程构造物主要指路基、路面、桥涵、隧道及其附属构造物和排水构造物。在路基施工前，通过测量放样确定路线中线桩、公路用地界桩、路堑坡顶、路堤坡脚、边沟等构造物的施工位置；在施工过程中，通过测量放样对工程构造物外形几何尺寸进行控制和检测，及时修正偏差，以准确体现设计意图；在工程竣工后，通过测量对工程进行质量检查和验收。实践证明，精确地测量放样能准确控制施工质量和节约工程成本。因此，施工放样是工程施工过程中的重要一环，它贯穿工程施工全过程。本文对其进行了一些探讨.内蒙古交通职业技术学院毕业设计（论文）-3-3第一章施工放样的基本方法1.1已知距离的放样距离放样即在地面上测设某已知水平距离，就是在实地上从一点开始，按给定的方向，量测出设计所需的距离定出终点。（1）钢尺量距在地面上丈量已有两点间的直线距离时，应先用尺子量出两点间的距离，再考虑必要的改正数，以求得正确的水平距离。而在地面上定出已给长度的直线时，其程序恰恰相反。先要根据已知的水平距离，结合地面的高低、钢尺的实际长度、丈量时的温度等，算出地面上应量的距离，并按算出的距离进行丈量。如图1所示。其计算公式为：htoLLLDD式中：D______名义长度，实地要测设的长度；D_______实际长度，需要测设的水平距离；oL______尺长改正数，钢尺在标准拉力、标准温度条件下钢尺的实际长度tL与钢尺的名义长度oL的差，即oL=tL－oL；tL______温度改正数，DttLot)(，为钢尺的线膨胀系数，一般用１．25×10－5／℃，ｔ为测设时的温度，ot为钢尺的标准温度（一般为20℃）；hL______倾斜改正数，DhLh22，h为两端点的高差；为了计算以上各改正数，应已知所用钢尺的尺长改正数，测出两端点的高差h，并测量测设时的温度t。图1(2）用全站仪测设水平距离在测量技术飞速发展的今天，测距仪或全站仪的使用越来越普遍。而且用测距仪或全站仪测距是目前施工测量中较为简捷和精确的一种方法。采用具有自动跟踪功能的内蒙古交通职业技术学院毕业设计（论文）-4-4测距仪测设水平距离时，仪器自动进行气象改正并将倾斜距离改算成水平距离直接显示。具体方法如下：测设时，将仪器安置在A点，图2测出气温及气压，并输入仪器，此时按测量水平距离功能键和自动跟踪功能键，一人手持反光镜杆立在终点附近，只要观测者指挥手持反光镜者沿已知方向线前后移动棱镜，观测者即能在测距仪显示屏上测得顺时的水平距离。当显示值等于待测设的已知水平距离D时，即可定出终点。如图3所示。已知高程的放样1.2已知高程的放样已知高程的放样是根据施工现场已有的水准点，用水准测量或三角高程测量的方法，将设计的高程测设到地面上，即根据一个已知高程的点，来测设另一个点的高程，使其高差为所指定的数值。(1）水准测量法如图3所示，A为已知水准点，其高程为AH，B为待测设高程点，其设计高程为BH。将水准仪安置在A和B之间，后视A点水准尺的读数为a，则B点的前视读数b应为视线高减去设计高程BH，即：BAHaHb)(图3测设时，将B点水准尺贴靠在木桩的一侧，上、下移动尺子直至前视尺的读数为b时，再沿尺子底面在木桩侧面画一刻线，此线即为B点的设计高程BH的位置。内蒙古交通职业技术学院毕业设计（论文）-5-5(2）三角高程法用三角高程测量的方法放样已知高程的操作步骤基本和水准测量的方法相同，具体操作如下：1）将仪器（经纬仪和测距仪或全站仪）安置于已知高程点A上，量取仪器高i；2）在待测高程点B上立棱镜，量取觇标高；3）测出A点与B点间的水平距离D和仪器视线的倾角，按公式fiDHBtan为地球和大气的改正数），并于已知高程BH进行比较；4）改变觇标高，重复第3）部，直至BBHH，即放样完成。1.3已知点的放样测设点的平面位置常用的方法有极坐标法、直角坐标法、角度交会法和全站仪法。放样时，应根据控制网的形式、控制点的分布情况、地形条件以及放样精度，合理选用适当的测设方法。(1）极坐标法极坐标法是指在建立的极坐标系中，通过待测点的极径和极角，也就是根据水平角和水平距离测设点的平面位置的方法。此方法适用于经纬仪配合测距仪或全站仪测设。在施工现场通常是以导线边、施工基线或建筑物的主轴线为极轴；以某一个已在现场标定出来的点位极点。放样时先根据待测点的坐标和已知点的坐标，反算待测点到极点的水平距离D（极径）和极点到待测点方向的坐标方位角，再根据方位角求算出水平角（极角），然后由D和进行点的放样，在这里D和称为放样数据。如图4所示，A、B为地面上已有的控制点，其坐标分别为Ax、Ay和Bx、By；欲测设P点，其设计坐标为Px、Py。则：22)()(cossinAPAPAPAPAPAPyyxxxxyyDABAP其中：ABABABABABxyxxyyarctanarctanAPAPAPAPAPxyxxyyarctanarctan图4内蒙古交通职业技术学院毕业设计（论文）-6-6测设时，在A点安置经纬仪，瞄准B点，先测设出角，得AP方向线。在此方向线上测设水平距离D，即得到P点。(2）角度交