工程渣土的工程特性及矿坑填埋场的工后沉降和容量分析

为了研究工程渣土的物理力学特性，并提出增加矿坑填埋场容量利用率和减少工后沉降的填埋方法，对堆填年限为5 a、处于积水填埋工况的湖州德清花山填埋场进行调查研究. 通过原位测试及室内试验发现，工程渣土成分复杂，具有低渗透性、高压缩性、抗剪强度随水的质量分数增加而减小等工程特性，矿坑填埋场压实度低，地基承载力低，土体大多处于饱和状态，固结缓慢. 利用LANDFILL程序对填埋场进行沉降与容量分析，发现在积水填埋工况下，矿坑容量利用率低，且工后沉降大，不适合直接用作农业用地或建设用地；在不积水填埋条件下进行工程渣土回填或降低地下水位能大幅度提高矿坑容量，并有效减少工后沉降. 研究结果为填埋场安全及容量设计、地基处理和地下建筑物施工提供了优化方向、理论依据和数据参考.

Engineering properties of excavated soil and analysis of post-construction settlement and capacity for pit landfill

The Huashan landfill in Deqing, Huzhou was investigated which had a 5-year landfill life and was in the condition of water landfill, in order to study the physical and mechanical properties of excavated soil and propose landfill methods to increase the capacity utilization rate of pit landfill and reduce the post-construction settlement. In-situ test and laboratory test indicate that the excavated soil has complex composition, low permeability, high compressibility, and the shear strength of it decreases with the increase of water mass fraction. And the compaction degree of the pit landfill, the bearing capacity of the foundation and the degree of consolidation are low. The LANDFILL program was used to analyse the settlement and the capacity of the pit landfill, and results show that the capacity utilization rate of the pit landfill is low, the post-construction settlement is large and it is not suitable to be directly used for agricultural land or construction land under the condition of water landfill. The capacity of the pit landfill can be greatly increased and the post-construction settlement can be effectively reduced by backfilling excavated soil under the condition of no water filling or lowering ground water. Results provided optimization direction, theoretical basis and data reference for the safety and capacity design of landfill, the foundation treatment and the underground building construction in excavated soil landfill areas.