沉井施工方案.doc

沉井是在地面或地坑上，先制作开口钢筋混凝土筒身，达到一定强度后，在井筒内分层挖土、运土，随着井内土面逐渐降低，沉井筒身借其自重克服与土壁之间的摩阻力，不断下沉而就位的一种深基或地下工程施工工艺。
沉井结构和沉井施工的特点是：沉井结构截面尺寸和刚度大，承载力高，抗渗、耐久性好，内部空间可资利用，可用于很大深度地下工程的施工，深度可达50m；施工不需复杂的机具设备，在排水和不排水情况下均能施工；可用于各种复杂地形、地质和场地狭窄条件下施工，对邻近建筑物、构筑物影响较小；当沉井尺寸较大，在制作和下沉时，均能使用机械化施工；比大开挖施工，可大大减少挖、运、回填土方量河加快施工速度，降低施工费用。本工艺标准适用于工业与民用建筑的深坑、地下室、水泵房、设备深基础、桥墩、码头等沉井工程。
一、材料要求
1．水泥
用425号或525号普通硅酸盐水泥或矿渣硅酸盐水泥，新鲜无结块。
2．砂
粗砂或中砂，含泥量不大于
Sunk in the ground or pit, the first production opening reinforced concrete Flashlight, after a certain intensity, in the well bore stratified excavation, earth, soil surface decreased with the wells, caisson Flashlight overcome by its weight wall friction between the soil, constantly sinking in place of a deep underground base, or construction technology.
Caisson caisson construction of the structure and characteristics: caisson structure dimensions, and rigidity, high bearing capacity, permeability, durability, interior space available and can be used for very deep underground works, the depth of up to 50m; construction does not require complicated machinery equipment, in the case of water and can not drain construction; can be used for a variety of complex topography, geology, and the narrow space under construction, on adjacent buildings and structures less affected; when the caisson size greater production and sink, can use the mechanical construction; than large excavation can greatly reduce the digging, transport, backfill earthwork River speeding up, reducing construction costs. This technology is applicable to industrial and civil construction pit, basement, pump house, equipment, deep foundation, piers, docks and other open caisson construction.
1, material requirements
1. Cement
425 or 525 with Portland cement or slag cement, fresh non-caking.
2. Sand
Coarse sand or in sand, mud content is not more than