百色水利枢纽大坝及地下厂房施工方法研究

Study on the Construction Method for the Dam and Underground Powerhouse of Baise Project

大坝及地下厂房是百色水利枢纽主体工程施工的关键，施工时间短，工程量相对较大。大坝施工土石方开挖总量为159.08万m3，最大开挖强度为8．42万m3／月，月钻灌强度达2．9万m，大坝RCC工程量为27．36万m3。经比较，RCC运输采用斜坡道把车与自卸汽车联合运输入仓方式，设置4条坝内斜坡道运输线和6条坝外斜坡道运输线。在大坝温度控制方面，底层埋设水管，其上层坝体层厚1～2m，每2～4d浇筑1层。地下厂房施工重点主要是主副厂房的洞室开挖，主副厂房断面为135.2m×21.2m×50m，自上而下布置上、中、下3层施工通道，分7层施工，每层4～8m；先挖顶拱，然后逐层下挖，喷锚支护与开挖平行作业，月平均洞挖进尺45m，最大洞挖强度0.75万m3／月。厂房混凝土工程量为2.17万m3，至第1台机组发电的工期为44个月。

Construction of the dam and underground powerhouse is the key of construction of Baise Project which is short in construction period and large in working volume. In the construction of the dam, the total volume of earth - rock excavation will be 1. 5908 Mm3 with maximum intensity of excavation being 84200m3 per month, the intensity of drilling and grouting will be 2900 m per month and the volume of RCC 273600m3. The RCC of dam will be transported and placed jointly by ramp tows and self - emptying trucks.For this purpose 4 ramp transits Inside the dam and 6 ramp transits outside the dam should be set. For temperature control, water pipes should be embedded on bottom layer, on top of which the RCC of the dam should be placed in layers 1 - 2 m in thicknessfor each with Intensity of placement being 1 layer every 2 to 4 days. Excavation of caverns for machine hall and auxiliary plant is the key of the construction of underground powerhouse. The section of the machine hall and auxiliary plant will be 135. 2m × 21. 2m × 50m. Three layers of construction accesses(upper, middle and lower)will be set from above to below and the construction will be conducted in 7 layers with 4 -8m in height for each. The ore,wn will be excavated first and the excavation will be conducted downward layer by layer with support by shotcrete and anchorage in parallel. The monthly mean excavation footage of cavern will be 45m with maximurn intensity of excavation being 7500m3 Per month. The total volume of concrete for the powerhouse will be 21700m3. The coastr-notion Pened till the operation of the first unit is scheduled to be 44 months.