摘要
文中首先介绍了在软弱地基中,设置碎石桩的常规施工方法,提出了用碎石桩法加固地基的机理,这就是桩体作用、垫层作用和砂井作用。根据若干工程的观测资料,对地基土强度在制桩前后的变化、桩土应力比和施工振动影响等问题进行了讨论。最后,用实例介绍了采用不打到硬层的短碎石桩处理深厚软基的成功经验。
In this paper conventional construction procedure is briefly described for the installation of stone columns in soft ground in China. A viewpoint concerning the mechanism of ground improvement by use of stone columns is presented for discussion, The author considers that stonecolumns used for reinforcing the soft ground have three functions, i.e. acting as concrete piles, as a mat and as sand drains. Based on the information obtained from field measurement and observation three important problems related to the construction and design of stone columns are discussed. These problems are the strength change of intervening native soil before and after stone column installation, the stress concentration ratio and the influence of vibration induced during stone columns installation on nearby structures. Finally, a case history is given to show that short stone columns not resting on a firm bearing stratum may in some instances be used to improve the weak strata of great thickness.
