混凝土拱坝设计

摘要

A江水利枢纽同时兼有防洪，发电，灌溉，渔业等综合作用，水库正常蓄水位184.5m，设计洪水位186.7m，校核洪水位189.5m，汛前限制水位182m，死水位164m，尾水位103.5m。水库死库容9.3亿m3，总库容12亿m3。

A江水利枢纽工程等级为一等，工程规模为大（1）型工程，主要建筑物级别为1级，次要建筑物级别为3级，临时性建筑物级别为4级。

A江水利枢纽的主要组成建筑物有挡水建筑物，主副厂房，泄水建筑物，过木筏道等。

挡水建筑物是一变圆心变外半径的双曲拱坝，坝顶弧长347m，最大坝高99m，坝底厚27m，坝顶宽8.0m。

泄水建筑物由两个浅孔和两个中孔组成：浅孔位于两岸，孔口宽9.0m，高9.0m，进口底高程为164m，出口底高程为154m；中孔位于水电站进水口两侧，孔口宽7.0m，高7.5m，进口底高程为135m，出口底高程为130m。在坝身泄水孔的上下游侧分别布置检修闸门和工作闸门，检修闸门采用平板门，工作闸门采用弧形闸门，在每一个工作闸门的上方有启闭机房，浅孔启闭机房高程为176m，中孔启闭机房高程为150m。泄槽支撑结构采用框架式结构。坎顶高程为118m，浅孔反弧半径为30m，中孔反弧半径为40m。泄槽直线段的坡度与孔身底部坡度一致,挑射角浅孔和中孔均为θ=20，，导墙厚度为1.0m，浅孔导墙高度为8m，中孔导墙高度为8.5m。

坝后式厂房装有4台5万kw的发电机组，主厂房长81m，宽18m，副厂房长66m，宽10m，安装场长21m，宽18m。压力管道的直径为4.5m，发电机层高程为114.8m，尾水管底高程为90.8m，厂房进水口底高程为152.3m。

为防止坝基渗漏，在坝基靠近上游侧进行帷幕灌浆，并且为了减少坝基的扬压力，在灌浆帷幕之后设置排水孔。

为了防止混凝土产生裂缝，拱坝坝体设置横缝，横缝面上需设置键槽，以咬合加固，增强坝体的抗剪能力。当底宽在40～50m以上的拱坝，才考虑设置纵横缝，而本设计中，拱坝坝底宽为27m，小于40m，故可不设置纵缝。

变半径变中心角拱坝设计

Abstract

Ajiang hydrocomplex play parts in flood control,water power,irrigation,water conservancy related fisheries,and so on.The reservoir normal water level is 184.5m,design flood level is 186.7m,maximum flood level is 189.5m,flood control level is 182m,dead water level is 164m,and tailwater level of hydropower station is 103.5m.The dead reservoir capacity is 930,000,000m3,and the total reservoir capacity is 1,200,000,000 m3. The hydraulic engineering grade is Grade I.

The hydroproject is consist of water retaining structure,power house,auxiliary room,sluice structure,raft sluice,and so on.

The water retaining structure is a double curvature arch dam.The length of the axis of crest dam is about 347m.Maximum height of the dam is 100m,the thickness of the bottom of the dam is 27m,and the width of the top of the dam is 8.0m.

The release structure is comprised of 2 mid-level outlet and 2 short-level outlet.The width of the mid-level outlet is 7.0m,and the height is 7.5m;the width of the short-level outlet is 9.0m,and the height is 9.0m.The upstream and the downstream side of every outlet are a bulkhead gate and a operating gate which is a radial gate.There is a room where a gate hoist is put above every service gate.The two rooms which are above the mid-level outlet service gate are at an elevation of 150 metres,and the other two rooms are at an elevation of 176 metres.The intake of the mid-level outlet is at an elevation of 135 metres,and the intake of the short-level outlet is at an elevation of 164 metres.

The type of the power house is at damtoe.The dimensions of the power house and the auxiliary room are 81m×18m and 66m×10m.The generator floor is at an elevation of 114.8 metres,and the bottom of the draft tube is at an elevation of 90.8 metres,and the intake of hydropower station is at an elevation of 152.3 metres.

In case of leakage of the dam foundation,there is grouting curtain at the base of the dam,behind which there are drainage holes which decrease the uplift pressure of the dam foundation.

In radial directions there are transverse joints in which there are keys,and because the thickness of the bottom of the dam is smaller than 40～50 metres,there is no longitudinal joint.