滇池流域软土灾害效应分析及应对措施

Analysis of Soft Soil Disaster Effects and Countermeasures for Dianchi Basin

滇池流域湖相沉积的软土中有分布范围广深厚的泥炭质土,因其具有压缩性高、强度低及蠕变量大等特点,此类场地上的工程建设中事故频发。收集此类场地上的深基坑、桩基及地基等方面的案例,对其事故产生的原因、灾害效应、治理措施及效果进行研究分析,探索事故灾害效应的控制及防范措施。分析结果表明:土方开挖要遵循分块、分段、分层、平衡、时效原则;此类软土蠕变量大,基坑内支撑结构要有足够的刚度,先撑后挖,临空面暴露时间不能长;软土蠕变会造成锚索锚拉力不足,支护桩倾斜变形;内支撑要控制立柱桩变形,防止土质太软立柱桩变形大,造成内撑结构破坏;要控制场地周围堆载范围及高度,不当会造成软土场地产生深层滑移等。本研究可为此类场地上的工程设计及施工提供参考。

The soft soils deposited in the lake phase of Dianchi basin have a wide distribution of deep peaty soils,which are characterized by high compressibility,low strength and high creep,and accidents are frequent in the construction of such sites.We collect cases of deep foundation pits,pile foundations and foundations on such sites,study and analyze the causes of accidents,disaster effects,management measures and effects,and explore the control and preventive measures of accidental disaster effects.The analysis results show that:the excavation should follow the principles of blocking,segmentation,stratification,balance and timing;creep of such soft soil is large,the support structure inside the pit should have sufficient stiffness,support should be readybecard excavation,and the exposure time of the critical surface should not be long;creep of soft soil will cause insufficient anchor and tilt deformation of the support pile;the internal support should control the deformation of the column pile to prevent the deformation when the soil is too soft,causing the destruction of the internal support structure;the range and height of the pile load around the site,should be controlled properly,otherwise deep slippage may occur.This research can provide reference for the engineering design and construction on such sites.