某邮轮码头后沿深厚抛石地基中的临水基坑设计

抛石地基中的临水基坑围护所处的周边环境条件和地质条件比较复杂,与常规基坑围护工程有较大区别,常规的围护结构形式并不能完全适用。结合某邮轮码头后沿的临水基坑工程设计,解决了地质条件复杂、环境保护要求高、防水技术难度大等难题。首先分析计算基坑围护设计比选方案,其次利用围井抽水试验,对冲孔咬合桩、冲孔灌注桩+高压旋喷桩两种不同围护方案止水效果进行对比。试验结果表明:冲孔咬合桩兼有支护和止水帷幕的双重作用,在抛石地基的临水基坑中实施效果较好,最终确定采用冲孔咬合桩作为围护方案。随后利用有限元分析软件Plaxis 2D,研究了该围护方案对周边既有码头结构的影响。在临海的深厚抛石层中采用冲孔咬合桩结构设计方案,具有结构安全、可靠,止水效果好的特点,较成功地解决了该复杂环境条件下基坑工程施工难、止水难的技术难题,可为类似工程提供参考和借鉴。

Design of excavation in waterfront areas in deep riprap foundation behind cruise terminal

The surroundings and geological conditions of waterfront excavation enclosure in deep riprap foundation are very complex,which are quite different from those of conventional foundation excavation enclosure.The traditional enclosure structures cannot be fully applied in the complex conditions.In this paper,the design of waterfront excavation in deep riprap foundation behind a cruise terminal is referred to solve the difficult problems of complex geological conditions,high environmental protection requirements,difficulty in waterproof technology and so on.Firstly,two excavation enclosure schemes are proposed to comparatively analyze through calculation.Secondly,based on pumping test of enclosed well,the water sealing effects of two different enclosure schemes,concluding piercing occlusion pile and piercing grouting pile together with high pressure jet grouting pile,are compared.The test results show that the piercing occlusion pile has the dual functions of supporting and water-proof curtain,and can be implemented well in waterfront excavation in riprap foundation.Then the piercing occlusion pile is determined to be excavation enclosure scheme.Finally,a model is established by the software Plaxis 2D to analyze the deformation of recommendation excavation enclosure scheme on the adjacent wharf.The design scheme of piercing occlusion pile adopted in the deep riprap layer near the sea has the characteristics of structural safety,reliability and good sealing effect.It successfully works out the difficult technical problems of construction and water sealing under the complex environment.And it can provide reference for similar excavation projects.