四川省某微丘地区拟建一公路小桥,其下游不远原有一座单孔净跨径为5.4m的钢筋混凝土板式桥,两岸桥台具有八字翼墙。桥下河底加固采用碎石垫层上厚20㎝的片石单层铺砌,纵向坡度i=20%。桥头路基高3.4m,经调查知某次历史洪水位离路基的路肩边缘高尚有1m。洪水时估计桥下平均水深为2m,此桥汇水面积F=6Km 2 ,河床土质为大砾石带砂和小砾石。求天然洪峰流量Q n 。(已知v y =4m/s,v 0 =1.1m/s,φ=0.9,M=1.46,S=1.22)
【简答题】Complete the words. ► I often do s h i f t work. shift 1 I belong to a t_ _ _ _ union. ____ 2 We went on st_ _ _ _ last year. ____ 3 Do you get an annual b_ _ _ s? ____ 4 Our w_ _ _ ...
【简答题】阅读短文,判断正(T)误(F)。 Hello! I'm Tom. I often walk to school. But yesterday I went to school by bus. Tomorrow I'm going to school by car. Because my father has a car. He often goes to work by car. Yesterda...
【单选题】M: How do you usually go to work?W: I ualy 80 by bike. Bul I went by bus yerday My bike needs repairing. Why did the woman go to work by bus yesterday?