保温保压浇筑蜗壳二期混凝土的施工技术

蜗壳二期混凝土被称为水电站厂房混凝土的“心脏”，是最关键和最难浇筑的部位。三峡左岸电站厂房采用对蜗壳充水保温保压模拟运转状态浇筑二期混凝土。该技术是一项新技术，目前在国内外尚属首例，施工质量对机组的安全运行及振动稳定具有至关重要的作用。施工中针对保温保压浇筑蜗壳二期混凝土的技术特点，采取了相应的施工措施，如实施严格的混凝土温控，严格的施工监测，科学的分层分块，选择最佳的混凝土浇筑设备，严格控制混凝土配合比。通过这些施工措施，在有关各方的共同努力下，保证了混凝土浇筑质量，达到了预期效果。

Construction technique of the second-stage concrete of spiral case under the conditions of heat and pressure preservation

The second-stage concrete of spiral case is c alled the core of the powerhouse concrete of hydropower station and is the most difficult to pour it. In the construction of the powerhouse of left-bank power plant of the Three Gorges Project, the second-stage concrete of spiral case was poured under the conditions of heat and pressure preservation. It is a new technique and is the first at home and abroad at present so that the construction quality is key to the safe operation, vibration and stability of generating unit. In the construction, the following measures were adopted, such as strict concrete temperature control, strict construction supervision, scientific zoning and blocking of concrete, the selection of the optimal concrete pouring equipment, strict mix proportion of concrete. With these measures and the concerted efforts by the parties concerned, the concrete pouring quality is ensured and reached expected effectiveness.