合力土工布分析在路基填筑施工期间的观测
合力土工布分析在路基填筑施工期间的观测
Force analysis of Geotextile in the observation during the subgrade filling construction
In the observation during the subgrade filling construction can be divided into three stages:In 1, the first phase: soil filling is completed, due to soil deadweight consolidation formed settlement, a substrate for silty clay with large water content, the settlement is more obvious.
2、第二阶段:1、地表沉降:路堤填土高度较低时，路堤的填筑速率较缓慢，相应的沉降速率不高，沉降量不大。现随着路堤填筑速度加快，随着荷载增加，清淤底部沉降随着增加，沉降速率开始加快，且向深度方向发展。当路堤填筑至设计标高，待土体排水固结完成后，抽取路基东侧排水沟的积水，相应范围内的沉降已基本完成。土工布地基沉降基本稳定，地基刚度明显提高。
2, stage second: 1, surface settlement: embankment height is low, the embankment fill rate is slow, the settlement rate is not high, the settlement quantity. Now as the embankment filling speed, with the increase of the load, Desilting Bottom subsidence increases, rate of settlement began to accelerate,to the depth direction. When the embankment to the design elevation for soil, drainage consolidation is completed, extraction embankment East drain water, the corresponding range of settlement has been basically completed. Geosynthetics foundation settlement basic stability, foundation stiffness increased significantly.
2, lateral displacement of embankment surface: in the process of pile side is mainly horizontal displacement, vertical displacement is very small. Side pile lateral displacement increases with the height of fill. Subgrade side pile completed, basic stop moving, subgrade slope toe no bulge phenomenon.
3、第二阶段:沉降、位移观测分析:在路堤填土过程中，软基不仅产生竖向沉降，同时产生侧向位移。在加载初期，竖向的沉降的增加明显比侧向位移快，主要是加载初期，山皮土的硬壳层及土工布、对附加应力有分散作用，同时阻碍了软土地基侧向变形的发展，随着加载继续进行，硬壳层对加载的影响不断降低，侧向位移的增长速率逐渐增大，侧向位移既包括由于填土产生的剪切体积变形，即瞬时沉降，还包括由于地基因土体固结产生的侧向位移。因清淤底面粉质粘土厚度为50～70cm，下层为淤泥质粘土，含水量在50%～60%，竖向沉降主要集中在这一层上。随着路堤填土的进行，这一层软粘土的侧向位移随之逐渐增大，至完成路堤填土时为止，最大位移量为15.4mm。路堤填筑停止时，软土地基的侧向位移几乎没有，这是软土地基固结较快，相应的侧向位移很快趋于稳定的原因，同时说明，如果控制好填筑速率，固结沉降在侧向产生的位移量就不大，在停载时间内，竖向位移继续发展，侧向位移呈现停止的状态。掌握以上三个阶段可以据此有计划的施工。