边坡支护及土方开挖方案.doc

一、 主厂房区域基础开挖特点：
1、 根据地质资料，主厂房区域地表下的淤泥层深达10m，主厂房基础一般座落在③淤泥质粉质土层中。本工程土建结构位于软土地基上，桩基保护是本工程土建基础施工的一大重点和难点。
2、 主厂房内部基础埋深相差较大，汽机基础比汽机间框架基础深3.5m；凝泵坑基础比汽机基础深0.5m；循环水阀门井及其相邻的A排基础底板整体现浇，底标高比汽机基础深1m、比A排其它基础深4.5m；A排外进排水管比A排其它基础深2.9m。这些布置特点，大大增加了土建地下部分的施工难度，给桩基保护提出了更高的要求。
3、保证桩基不发生位移偏位现象，拟采取必要的支护措施即水泥搅拌桩支护方案，在主厂房基坑四周布置多排水泥搅拌桩，形成水泥土挡墙。
4、土方开挖底标高已低于地下水位，淤泥质土层的透水性很小，降水效果不明显。 
二、 支护方案
1、 在主厂房基坑周边、烟囱基坑周边、循环水管沟基坑周边，布置水泥搅拌桩。
锅炉房、除氧煤仓间、汽机房（除A排）基坑，布置四排双头水泥搅拌
First, the foundation excavation of the main powerhouse features:
1, according to geological data, the main plant area of surface layer of silt under the deep 10m, based on generally located in the main building ③ silty soil. The civil works structures located in soft soil, pile protection is the basis of the civil works construction of a major important and difficult.
2, the main difference between the plant and the basis of depth greater than the steam turbine steam turbine foundation based on inter-frame depth 3.5m; condensate pump steam turbine foundation pit of deep foundation than 0.5m; recycled water wells and the adjacent A valve arrangement of the base as a whole is casting, the bottom elevation than the turbine foundation depth 1m, other than the basic A row of deep 4.5m; A exclusion into the basis of drainage other than the A row of deep 2.9m. The layout features, which greatly increased the difficulty of civil underground construction, pile protection to a higher demand.
3, to ensure that displacement does not occur pile deviation phenomenon, to be taken the necessary support measures that support the program of cement mixing pile, arranged around the pit in the main plant more rows of cement mixing to form a cement retaining wall.
4, the end of earth excavation below the water table elevation has, silty soil permeability is small, the precipitation effect was not obvious.
Second, support programs
1, in the main plant around the foundation, chimney foundation pit, circle pit around the pipe trench, decorated cement mixing pile.
Boiler room, oxygen removal coal bin, the steam room (except row A) excavation, cement-head arrangement of four rows