大型沉井基础的防冲护底试验研究

大型沉井基础的冲刷防护是较复杂的工程问题，既要求防护材料的块径不能过小以确保安全度汛，又不能因其块径过大而影响着床时沉井刃脚的下切。采用物理模型，通过试验对护底碎石的块径、级配及起动、安全度汛和着床阶段的沉井防护工程的稳定性进行研究，得出大型沉井基础在安全度汛和着床两种阶段既能保持稳定又较为经济的护底工程的范围和碎石级配。既能满足施工需要，又使整体预防护工程达到总体要求。

Anti-Scouring Experimental Study of Bed Protection for Large Open Caissons

It is a complex engineering problem to protect foundation beds for large open-caissons against bed-scouring. The size of the protecting materials should be neither too small to ensure safety against floods nor too big to affect the cut-in of the open caissons. By physical model testing, the size and gradation of crushed rocks for bed protecting and the stability of the bed protection for open caissons in the process of maneuvering, flooding control and bed-sitting were studied. The range of bed protection and the gradation of crushed rocks for bed protection were thus achieved to make the bed protection for large open caissons not only stable but also more economical during flooding and bed-sitting operations, which can not only satisfy the construction needs but also make the overall bed protection meet the general requirements.