路基沉降变形监测一、路基工点类型本标段正线全长39.353km,路基长4.822km,占线路长度的12%,路基工点类型主要有低矮路堤、短路基、边坡防护路基、高路堤、深路堑、地下水路堑、膨胀土(岩)路堑、陡坡路基、基床处理路基、浸水路基、不良地质路基(包括危岩落石、顺层等)、特殊岩土路基(包括软土、松软土地基)二、观测断面及点的设置原则1、路基沉降监测1.1路基沉降监测的要求1)、路基沉降观测应以路基面沉降和地基沉降观测为主。沉降变形观测断面应根据不同的地基条件,不同的结构部位等具体情况设置;测点的设置位置应满足设计要求,同时还应针对施工掌握的地质、地形等情况调整或增设。2)路基面和地基沉降观测点应设在同一横断面上。3)测点及元器件的埋设位置应符合设计要求,且标设准确、埋设稳定。1.2、观测断面及点的设置、元件布设观测断面的设置及观测断面的观测内容、元件的布设应根据地形、地质条件、地基压缩层厚度、路堤高度、地基处理方法、堆载预压等具体情况,结合沉降预测方法和工期要求具体确定。分以下几种布设形式。1)、路基沉降变形监测断面元件布置示意图A型A型断面监测2)、路基沉降变形监测断面元件布置示意图B型B型断面监测3)、路基沉降变形监测断面元件布置示意图C型C型断面监测4)、路基沉降变形监测断面元件布置示意图D型D型断面监测吉图珲客专JHSⅦ标路基沉降工点布置表及断面类型序号路基工点断面里程沉降监测断面类型1GDK323+260A型断面监测2GDK323+359A型断面监测3GDK323+400A型断面监测4GDK323+310B型断面监测5GDK323+379B型断面监测6GDK323+015D型断面监测7GDK323+095D型断面监测8GDK323+175D型断面监测9GDK323+488D型断面监测10GDK333+087A型断面监测11GDK333+117A型断面监测12GDK333+097B型断面监测13GDK333+136D型断面监测14GDK335+065A型断面监测15GDK335+055B型断面监测16GDK335+048D型断面监测17GDK339+020A型断面监测18GDK339+100A型断面监测19GDK339+130A型断面监测20GDK339+070B型断面监测21GDK339+120B型断面监测22GDK338+926D型断面监测23GDK338+980D型断面监测24GDK345+170A型断面监测25GDK345+200A型断面监测26GDK345+310A型断面监测27GDK345+372A型断面监测28GDK345+180B型断面监测29GDK345+360B型断面监测30GDK348+805A型断面监测31GDK348+870A型断面监测32GDK348+840B型断面监测33GDK348+880D型断面监测34GDK352+425A型断面监测35GDK352+459A型断面监测36GDK352+489A型断面监测37GDK352+479B型断面监测38GDK352+395D型断面监测39GDK354+314A型断面监测40GDK354+344A型断面监测41GDK354+443A型断面监测42GDK354+500A型断面监测43GDK354+614A型断面监测44GDK354+693A型断面监测45GDK354+850A型断面监测46GDK354+890A型断面监测47GDK354+978A型断面监测48GDK354+324B型断面监测49GDK354+453B型断面监测50GDK354+624B型断面监测51GDK354+683B型断面监测52GDK354+880B型断面监测53GDK354+380C型断面监测54GDK354+550C型断面监测55GDK354+940C型断面监测56GDK354+635D型断面监测57GDK354+720D型断面监测58GDK354+770D型断面监测59GDK354+820D型断面监测60GDK355+000A型断面监测61GDK355+600A型断面监测62GDK355+630A型断面监测63GDK354+998B型断面监测64GDK355+100D型断面监测65GDK355+200D型断面监测66GDK355+300D型断面监测67GDK355+400D型断面监测68GDK355+500D型断面监测69GDK355+570D型断面监测70GDK356+047A型断面监测71GDK356+077A型断面监测72GDK356+170A型断面监测73GDK356+249A型断面监测74GDK356+057B型断面监测75GDK356+239B型断面监测76GDK356+120C型断面监测77GDK356+280C型断面监测78GDK356+302D型断面监测79GDK358+583A型断面监测80GDK358+613A型断面监测81GDK358+603B型断面监测82GDK358+488D型断面监测83GDK358+560D型断面监测84GDK359+977A型断面监测85GDK360+007A型断面监测86GDK360+090A型断面监测87GDK360+120A型断面监测88GDK360+163A型断面监测89GDK360+249A型断面监测90GDK360+300A型断面监测91GDK360+340A型断面监测92GDK359+987B型断面监测93GDK360+110B型断面监测94GDK360+173B型断面监测95GDK360+259B型断面监测96GDK360+330B型断面监测97GDK360+050C型断面监测98GDK360+150C型断面监测99GDK360+200C型断面监测100GDK360+390C型断面监测101DK027+939D型断面监测102DK360+410A型断面监测103DK360+513A型断面监测104DK360+570A型断面监测105DK360+670A型断面监测106DK360+770A型断面监测107DK360+826A型断面监测108DK360+930A型断面监测109DK360+057A型断面监测110DK360+120A型断面监测111DK360+225A型断面监测112DK360+282A型断面监测113DK360+340A型断面监测114DK360+440A型断面监测115DK360+490A型断面监测116DK360+545A型断面监测117DK360+601A型断面监测118DK360+647A型断面监测119DK360+750A型断面监测120DK360+460B型断面监测121DK360+523B型断面监测122DK360+720B型断面监测123DK360+816B型断面监测124DK360+980B型断面监测125DK361+042B型断面监测126DK361+067B型断面监测127DK361+170B型断面监测128DK361+292B型断面监测129DK361+390B型断面监测130DK361+535B型断面监测131DK361+591B型断面监测132DK360+620C型断面监测133DK360+880C型断面监测134DK361+700C型断面监测2、路堑高边坡变形监测根据地质条件及工程实践经验,主要针对以下地质条件、边坡高度设置边坡位移、应力状态的监测系统:2.1、滑坡、堆积体等不良地质边坡;2.2、膨胀土及红粘土路堑边坡高度》10米;一般土质及风化层路堑边坡高度》15米;一般软质岩及软硬互层路堑边坡高度》20米;硬质岩路堑边坡高度》30米;2.3、顺层边坡或受构造影响不利结构面发育的边坡;每工点应有不少于2个边坡位移监测断面。结合路堑边坡的形式,分为以下3种监测断面形式1、Ⅰ型监测断面布置图(单位:米)2、Ⅱ型监测断面布置图3、Ⅲ型监测断面布置图本标段路堑边坡监测断面表序号边坡监测断面里程断面类型1GDK323+015I型监测断面2GDK323+065I型监测断面3GDK323+105I型监测断面4GDK349+220I型监测断面5GDK349+260I型监测断面6GDK349+300I型监测断面7GDK349+220Ⅲ型监测断面8GDK349+260Ⅲ型监测断面9GDK349+300Ⅲ型监测断面10GDK355+050I型监测断面11GDK355+090I型监测断面12GDK355+130I型监测断面13GDK355+180I型监测断面14GDK355+230I型监测断面15GDK355+280I型监测断面16GDK355+330I型监测断面17GDK355+380I型监测断面18GDK355+050Ⅱ型监测断面19GDK355+090Ⅱ型监测断面20GDK355+130Ⅱ型监测断面21GDK355+130Ⅲ型监测断面22GDK355+180Ⅲ型监测断面23GDK355+230Ⅲ型监测断面24GDK355+280Ⅲ型监测断面25GDK355+330Ⅲ型监测断面26GDK355+380Ⅲ型监测断面三、观测元件的选取、埋设3.1、观测元件的选取:应满足工后沉降的评估需要以及精度要求。路基面采用观测桩观测,地基面采用沉降板、剖面沉降管相结合进行观测。路堑高边坡采用位移监测桩进行观测。3.2、观测元件的埋设:观测元件除沉降观测桩外,均应在地基加固完成后路堤填筑施工前及高边坡路堑开挖至设计埋桩位置后埋设。1沉降观测桩(点)(1)在一般路基填筑至基床表层顶面,加载预压路堤填筑到基床底层顶面后,埋设沉降观测桩;路基面两侧观测桩一般设在距左右线路中心3.2m处(由于部分桩位会与接触网立柱基础、通信、信号电缆槽手孔有干扰,以后埋设的可改为2.7m处)。埋设规格见附图(2)要求填筑至基床表层顶面埋设观测桩,但若施工在施工过程中级配碎石等供应困难,架梁工期紧,也可在基床表层填筑20cm后,埋设路面观测桩。2沉降板:由钢底板、金属测杆(φ40mm厚壁铁管)及保护套管(直径不小于φ75mm、壁厚不小于4mm的硬PVC管)组成,钢底板尺寸为50cm×50cm,厚1cm;具体按设计图样焊接组装。沉降板应埋入褥垫层顶部嵌入不少于10cm,采用中粗砂回填密实,再套上保护套管,保护套管低于沉降板金属测杆,保护套管和金属测管上口均加盖封住管口,并在其周围填筑相应填料稳定保护套管,完成沉降板的埋设工作。采用水准仪按国家一等精密水准测量方法测量埋设就位的沉降板测杆杆顶标高作为初始读数(测量一定要准确),随着路基填筑施工逐渐接高沉降板测杆和保护套管,每次接长高度以1m为宜,接长前后测量杆顶标高变化量确定接高量。3、边桩示意图4、单点沉降计单点沉降计采用智能数码单点位移计,属智能位移传感器,由沉降盘、智能电感磁通调频位移计、导磁体、波纹管、测杆、测杆直螺纹接头、锚头,测试导线组成。单点沉降计有关图示5、路堑位移监测桩及其埋设大样图6、剖面沉降管:采用专用塑料硬管,其抗弯刚度应适应被测土体的竖向位移要求,管端接口密合。剖面沉降测量是将剖面沉降仪探头预埋在剖面沉降管槽内,按一定间距依次读数,起始端管口标高(设置水准点)采用水平仪按国家一等精密水准测量方法进行测量,再通过数据处理计算求出不同位置处地基的沉降量。剖面沉降管在褥垫层顶面开槽埋设(不是埋设在褥垫层底部),槽底中粗砂找平,表面回填5~10cm中粗砂并与褥垫层相平,两端部应进行有效保护。剖面沉降管埋设示意图四、过渡段沉降观测1、过渡段沉降观测应以路基面沉降和不均匀沉降观测为主,沉降观测期与路基相同,不少于6个月。3.5.2分别在路桥、路涵、路隧过渡段的结构物起点、距结构物起点5~10m处、15~25m处、50m处各设一个观测断面,沿涵洞轴线设路基面观测断面,每个观测断面设3个观测桩。按观测桩的50%埋设基底沉降板,按观测桩的25%埋设基底剖面沉降管。2、路堤和路堑过渡段在分界处设路基面观测断面,每个观测断面设3个观测桩3、沉降观测的频次不低于路基表2.5的规定。当环境条件发生变化或数据异常时应及时观测。4、路桥、路涵过渡段观测点和元器件