持力层
参考答案:
是指地基中直接支持建(构)筑物荷载的岩土层。
New York, _______last year,is a nice old city. [ ]
A. that I visited
B. which I visited
C. where I visited
D. in which I visited
200km/h≥线路允许速度Vmax≥250km/h正线上,根据《高速铁路无砟轨道线路修理规则》规定,线路轨道静态几何尺寸容许偏差管理值中,轨距变化率的经常保养标准为()。