流砂发生的根本原因是(      )

A.地下水渗流                                               

B.土体失重

C.动水压力的作用                                        

D.降水措施不当

在沉管灌注桩施工过程中，若拔桩过快，则可能发生(      )

A.断桩                                                          

B.桩尖进水进泥

C.吊脚桩                                                      

D.瓶颈桩

为了保证混凝土泵送的质量，每m3混凝土中水泥用量不小于(      )

A.200kg                                                        

B.250kg

C.300kg                                                        

D.350kg

钢模板用模数制设计，宽度模数以50mm进级，长度模数以多少进级？(      )

A.100mm                                                      

B.125mm

C.150mm                                                      

D.175mm

下列适用于钢绞线束的锚具是(      )

A.墩头锚具                                                   

B.螺杆锚具

C.多孔夹片锚具                                            

D.钢质锥形锚具