.钱塘海塘,近年来大量发展沉箱、沉井作为抛石丁坝坝头保护建筑物,对于防止坝头块石冲失,保护坝身,起了显著作用。但也有少数沉井,由于基础不够深和维护工作上的缺点,发生倾斜倒坍。沉箱、沉井基础,在合理范围内应尽量深些,但也不是愈深愈好。过分追求深基的作法,在技术上是不必要的,在经济上也是一种浪费。正确决定沉箱、沉井基础的深度在安全可靠的前提下做到施工方便,经济合理,是一个 Qiantang seawall, in recent years a large number of development of caissons, caisson as a throwing stone dam protection of buildings, to prevent the head block loss, dam protection, played a significant role. However, there are also a few open caverns that have been tilted and collapsed due to inadequate foundation and shortcomings in their work. Caisson, sink well foundation, within a reasonable range should be as deep as possible, but not as good as the better. Excessive pursuit of a deep foundation is technically unnecessary and economically wasteful. Correct determination of caissons, caisson depth of the foundation under the premise of safe and reliable to facilitate construction, economical and reasonable, is a