某公路跨越一河流,设计流量 Q s =3000m 3 /s ,河槽平均水深 h=9.52m 。若桥梁采用四孔 30m 简支梁结构,双柱式桥墩,墩径 1.4m ,冲刷前桥下过水面积 A q =1500m 2 ,天然桥下平均流速 v oM =1.759m/s ,河槽平均流速 v c =1.7m/s , d 50 =2.0mm 。 1 . 前最大壅水高度和桥下壅水高度。(须按讲课视频中的公式计算 υ M ’ 、υ M 、 K N 、 K Y 、△ Z、 △ Z ’ )
【简答题】____________________(不管这些有关水资源的预言是否成为现实), what cannot be denied is the fact that areas classified as 'barren' already occupied 60 percent of Asia in 1995.
【简答题】Students in his class cannot understand ____________. A.what does the sentence mean B.what means this sentence C.what this sentence means D.what is the meaning of the sentence