宁村水库重力坝初步设计水工建筑物计算

《水工建筑物》课程设计计算书——宁村水库重力坝初步设计班级：水利水电工程091学生：王朝阳指导教师：张小飞、段秋华完成时间：2013.1.23广西大学土木建筑工程学院目录一、工程等级的确定·······················································································3（一）原理··································································································3（二）计算过程····························································································3二、孔口尺寸拟定及设计洪水位、校核洪水位的确定············································3（一）堰顶高程的拟定··················································································3（二）堰顶溢流前沿宽度的拟定······································································3（三）设计洪水位、校核洪水位的计算·····························································4三、挡水坝设计······························································································4（一）坝顶高程的确定···················································································4（二）建基面高程的确定················································································5（三）坝顶宽度的确定···················································································5（四）上下游坝坡坡率及起坡点位置的确定·························································5（五）坝面优化·····························································································5（六）坝体强度稳定承载力极限状态设计····························································5（七）坝体上游面拉应力的正常使用极限状态设计················································5（八）坝体应力分析························································································5四、溢流坝设计······································································································5（一）溢流坝断面设计······················································································5（二）消能防冲设计·························································································8（三）导墙设计································································································9（四）坝体强度稳定极限状态设计······································································10（五）坝体正常使用极限状态合计······································································10五、大坝剖面优化和应力稳定分析··············································································10六、工程量与开挖量计算··························································································11七、附表···············································································································11（一）附表一：挡水坝电算方案·········································································11（二）附表二：溢流坝电算方案·········································································18宁村水库重力坝初步设计计算书一、工程等级的确定（一）原理：拟定泄水建筑物，进行调洪计算，求得校核洪水位，再根据附图1（宁村水库水位~库容关系曲线）查得水库总库容，最终根据规范《水利水电工程等级划分及洪水标准》SL252-2000确定工程等级。（二）计算过程：已知：在校核洪水（0.2%）下，Q=588m3/s；正常蓄水位126.50m；死水位106.00m。坝址岩层以砂岩为主，夹泥岩和页岩，砂岩抗压强度较高，但泥岩、页岩抗压强度稍低，其允许承载能力为0.6~0.7MPa，岩层倾向上游，岩石节理、裂隙发育，整体性稍差，并夹有软薄层，抗滑能力较低。下游河道平均水深2米左右。预计采用消能效果较好的消能工。综合地质条件、下游河道水深、枢纽布置和消能工设计，因此，通过技术经济比较后选定单宽流量q=28m3/(s·m)。则堰顶宽b=Q/q=588/28=21m由Hd=(0.7~0.95)H校，取Hd=0.85H校即Hw/Hd=0.85查图3可得m=0.490＜0.502，满足要求。式中：Hd为定型设计水头，m；Hw为堰上水头，m。根据公式Q=ε1σsmnbg2H3/2，式中：ε1：侧收缩系数，与边墩、闸墩及闸墩头部的型式、堰孔的数目、堰孔的尺寸、全大大大大的水头等有关，ε1=0.96；σs：淹没系数，为自由出流σs=1；n：堰孔数，本设计中为1；m：流量系数，由计算得出m=0.490；b：堰顶宽，由计算得出b=21m；g取9.81m2/s。带入公式有：H校=[Q/(ε1smnbg2)]2/3=[588/(0.96*1*0.490*21*81.9*2)]2/3=5.65mHd=0.85H校=0.85*5.65=4.80mZ校=126.50+5.65=132.15m查水位~库容关系曲线（图1）确定总库容V总=657.6（万m3）根据工程效益、总库容查询规范SL252—2000，该工程的等别为Ⅲ等。二、孔口尺寸拟定及设计洪水位、校核洪水位的确定（一）堰顶高程的拟定因为是开敞式溢流坝身泄水，并无调节等要求，因此堰顶高程就是正常蓄水位高程，即为126.50m。（二）堰顶溢流前沿宽度的拟定因为砂岩中还夹有泥岩、页岩等，砂岩本身强度也不高，且不完整，因此从消能防冲考虑，应按破碎岩石处理，单宽流量q=20～50m3/s，又综合考虑了以上四方面的因素，初步选定单宽流量q=28m3/(s·m)，按渲泄最大洪水时的流量Q校=588m3/s考虑，得到溢流前沿宽度为：L=Q校/q=588/28=21m（三）设计洪水位、校核洪水位的计算1、原理：试算法。首先假定一个堰上水头H设，计算H设/Hd值，查附图3，宁村水库Hw/Hd与流量系数m关系曲线，得出流量系数m，代入公式Q=ε1σsmnbg2H设3/2求出设计洪水H设。与资料给的设计洪水（2%）Q设=450m3/s比较，误差不超过1%即可。2、已知:由以上计算知堰顶高程为126.50m，单宽流量q=28m3/s，及前沿宽度L=21m。由确定工程等级过程推求得校核洪水位为Z校=132.15m。3、计算过程：通过多次试算结果简单列表如下：（表4）方案堰上水头H设（m）HdH设/Hd流量系数m设计洪水Q设（m3/s）设计洪水（2%）Q设（m3/s）误差一4.804.8010.501460.15450.002.25%二4.754.800.9900.500452.98450.000.66%三4.744.800.9880.500451.55450.000.34%四4.734.800.9850.500450.12450.000.03%经过多次试算，方案一、二、三不满足设计规范，方案四和方案五均满足设计要求，但方案五更为精确。故选定方案四作为设计依据。即H设=4.73m。推求设计洪水位：Z设=4.88+126.50=131.23m。三、挡水坝设计（一）坝顶高程的确定重力坝坝顶高程按坝顶上游防浪墙顶高程计，按下式计算，取其大值。防浪墙顶高程=设计洪水位+△h设防浪墙顶高程=校核洪水位+△h校其中设计洪水位、校核洪水位已计算得出，只需求△h即可。△h=h2%+hz+hc式中：h2%：累计频率为2%时的波浪高度；hz：波浪中心线高于静水位的高度；hc：安全加高，按表5选用。表5安全加高hc运用情况坝的级别123设计情况（基本情况）0.70.50.4校核情况（特殊情况）0.50.40.3根据官厅水库公式求h1%、hz：1、设计情况①高：hl=0.0166*V05/4D1/3=0.0166*275/4*31/3=1.474m由于gD/Vo2=9.81*3000/152=40.37在（20，250）之间，故为累计频率为5%的波高。h1%=1.24h5%=1.24*1.474=1.828m②波长：L=10.4(h1%)0.8=10.4*1.8280.8=16.851m③高：hz=(πh1%2/L)cth(2πH)/L=0.623m④表5得hc=0.4因此△h=h2%+hz+h=0.808+0.234+0.4=2.851mH=131.23+2.851=134.08m2、校核情况①波高：hl=0.0166*V05/4D1/3=0.0166*155/4*31/3=0.707m②波长：L=10.4(h1%)0.8=10.4*0.8770.8=9.363m③高：hz=(πh2%2/L)cth(2πH)/L=0.254m④表5得hc=0.3因此△h=h2%+hz+h=0.877+0.254+0.3=1.431mH=132.15+1.431=133.58m相比取大者，所以坝顶高程为134.08m。（二）建基面高程的确定根据该坝的地形地质条件，建基面可设在弱风化处，在高程为85m~86m附近，该设计取建基面高程为85.00m（三）坝顶宽度的确定根据《混凝土