【摘要】 为选择合理的围堰施工方案，以满足不断涌现的跨水域大跨度桥梁主墩深水基坑的安全稳定、施工高效。以位于软质岩地区的某特大桥主墩围堰为背景，通过数值模拟方法分析锁扣钢管桩围堰和双壁钢围堰两种方案的支护效果。结果表明：锁扣钢管桩围堰在受力变形、施工效率、机械投入、经济性等方面更具优势。与传统的双壁钢围堰相比，采用锁扣钢管桩围堰，围堰最大水平向变形减少了约27%,最大弯矩减小了约61%,内支撑所受轴力减小了58.88%,单个主墩围堰的施工周期可缩短22 d,材料回收率达到90%,回收材料可周转次数大于3次，施工总成本节约550万元。实际工程中采用锁扣钢管桩围堰施工方案，施工效果及现场监测结果表明：锁扣钢管桩围堰止水效果显著，最大变形在可控范围内，且与数值模拟结果较为吻合。研究成果对软质岩地区深水围堰基坑设计施工具有一定的借鉴意义。更多还原

【Abstract】 In order to choose a reasonable cofferdam construction scheme to meet the safety, stability and efficient construction of deep-water foundation pits for the main piers of large-span bridges across water areas that are emerging. Taking the cofferdam of the main pier of a super bridge in a soft rock area as the background, the supporting effects of the two schemes of locking steel pipe pile cofferdam and double-wall steel cofferdam were analyzed by numerical simulation method. The results show that the locking steel pipe pile cofferdam has more advantages in the aspects of stress deformation, construction efficiency, mechanical investment and economy. Compared with the traditional double-walled steel cofferdam, the use of the locking steel pipe pile cofferdam reduces the maximum horizontal deformation of the cofferdam by about 27%, the maximum bending moment by about 61%, and the axial force on the inner support. 58.88%, the construction period of a single main pier cofferdam can be shortened by 22 days, the material recovery rate can reach 90%, the number of recycled materials can be turned over more than 3 times, and the total construction cost can be saved by 5.5 million yuan. The construction plan of locking steel pipe pile cofferdam is adopted in the actual project. The construction effect and on-site monitoring results show that the water-stopping effect of locking steel pipe pile cofferdam is remarkable, and the maximum deformation is within the controllable range, which is in good agreement with the numerical simulation results. The research results have certain reference significance for the design and construction of deep-water cofferdam foundation pits in soft rock areas.更多还原