对大面积软弱地基处理技术的辩证思考

Dialectical thinking on treatment technology for large-area soft foundation

结合某项目大面积吹填软弱地基处理实践,阐明大面积软基处理方法一般为定性处理方法,其意义往往在于是一次"预处理";其目的是使一块无法直接上人、上设备,更无法直接作为天然地基使用的"毛地"变成一块可大兴土木的"宝地";其核心是"排水"和"固结"。大面积软基处理设计要求的确定应综合考虑时间成本和地基处理效果,以便达到最佳技术、经济效益。在深厚欠固结软基上直接成桩的错误观念和做法是造成很多基础工程质量事故的直接原因。大面积软基处理设计中预压荷载的组成、超载值以及基底附加压力的计算均应考虑处理土层和建(构)筑物基底土层的应力历史,结合场地使用荷载情况综合分析确定,以便有效控制后期沉降。

Based on the treatment practice of large-area soft ground, the treatment method for large-area soft foundation is generally qualitative. As far as some real estate construction projects which have strict requirements on foundation deformation control are concerned, the treatment technology of the large-area soft foundation always means pretreatment. The purpose is to make an area that cannot be directly entered by people and equipments and used the natural foundation as a place for putting up installations, and the core is inseparable from drainage and consolidation. In order to achieve the best technical and economic benefits, the time cost and the effect of foundation treatment should be considered into the design requirements of large-area soft foundation treatment. A lot of accidents are directly caused by wrong concepts and methods of piling in deep and soft ground. In the design, in order to effectively control settlement, the pressure load, overload value and calculation of basement additional pressure should consider the stress histories of soil and basement, and be determined by comprehensively analyzing the site load.