Determination and Evaluation of Strength Characteristics of Dry Jet Mixing

Dry jet mixing (DJM) for soft soil stabilization has been widely used since 1980s. The quality and strength of stabilized columns are fundamental parameters to evaluate the stabilization work. This paper presents the standard penetration test (SPT) method and its test results on cement columns. It is shown that SPT is an effective and simple method for inspecting and evaluating cement columns. The strength characteristics along the length of the column, a good correction between SPT blow count and the unconfined compressive strength are achieved.

试论连云港海相软土路堤沉降规律

根据连云港至徐州高速公路连云港段60多个断面的现场实测沉降资料,分析了在路堤荷载作用下连云港海相软土的沉降和固结规律。实测数据表明,在路堤荷载作用下连云港海相软土地基的沉降曲线符合双曲线形式,故可采用双曲线法预测最终沉降。由此可以分析在不同施工期的地基沉降和固结特性,得到不同地基处理条件下路堤填筑期和预压期地基平均固结度与施工时间的关系。分析亦表明,粉喷桩加固能加速地基的固结速率。最后,针对沉降和固结理论计算中计算参数的难以合理确定的局限性,对现场实测沉降数据采用数理统计方法,提出了适用于连云港地区海相软土路堤沉降和固结估算经验公式。