箱简型基础防波堤结构受力模式及合理尺度

防波堤向深水区域发展时，抛石堤、抛石基床和半圆体混合堤等传统结构基底宽度呈倍数增加，同时还必须对软土地基进行处理，工程造价大幅上升．针对天津港淤泥质软土地基情况，开发了一种不需要进行地基处理的防波堤结构——箱筒型基础防波堤结构．本结构由插入到地基土中的箱筒型基础结构和上部的挡浪结构组成，利用周边软土的黏聚力和摩擦阻力来保证结构的抗滑和抗倾稳定性，利用插入埋深来提高基底的承载力和整体稳定性，可预制且可重复利用．对结构抗滑、抗倾和地基承载力稳定性系数进行了计算研究，得出了优化的合理结构尺度，为箱筒型基础防波堤的实际工程应用奠定了基础，也为软土地基上新型深水防波堤的计算模式提供了借鉴．经比较，采用箱筒型基础防波堤结构较其他方案节省工程投资25．8％．

Force Mode and Reasonable Scale of Breakwater Structure with Bucket-Box Foundation

As the construction of breakwater develops in deep water, the foundation width of traditional structure such as rubble breakwater, rubble-mound foundation and semi-circular composite dike increases exponentially, and at the same time, the soft ground under the construction must be improved accordingly, which results in the massive increase of engineering cost. Therefore, in accordance with the characteristics of very soft ground at Tianjin port, a cylindrical caisson foundation breakwater was developed. The advantage of this breakwater is that there is no need to improve soft ground. The breakwater consists of two parts, the cylindrical caisson foundation which is inserted into ground and the upper wave wall structure. The mechanism is very simple. The stabilities against sliding and overturn- ing are supplied by the cohesive strength and frictional resistance of soft ground soil. The bearing capacity of the foundation and the stability of the whole structure depend on the depths inserted into ground. The construction can also be prefabricated and reused. And the research on structure stability against sliding and overturning and foundation bearing capacity is carried out, and the size structure gets optimized. The research results not only guide the application of cylindrical caisson foundation breakwater but also supply the reference to the calculation mode of such a new deep water breakwater on soft ground. Compared with the traditional structure, the proposed cylindrical caisson foundation breakwater saves cost by 25.8%.