STUDY ON CONSOLIDATION AND PERMEABILITY PROPERTIES OF LIANYUNGANG MARINE CLAY BASED ON PIEZOCONE PENETRATION TEST
STUDY ON CONSOLIDATION AND PERMEABILITY PROPERTIES OF LIANYUNGANG MARINE CLAY BASED ON PIEZOCONE PENETRATION TEST
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发表时间：
2007
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通讯作者：
Guangyin Du
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作者：
Guangyin Du
为了评价连云港海相粘土的固结渗透特性，通过室内固结试验和压电触探试验对其固结系数和渗透系数进行了研究，并根据现场监测沉降资料反分析了该粘土的水平固结系数。不同方法测得的水平固结系数的结果比较表明，压电触探测定的水平固结系数值在(3.0~6.5)×10-3cm2/S之间。通常是竖向固结系数的2-4倍。反分析得到的水平固结系数值略低于基于Teh和Houlsby方法的CPTU计算的水平固结系数。这可能是由于竖向排水沟安装过程中产生的涂抹效应所致。对于连云港海相粘土，建议采用Teh和Houlsby的方法，该方法考虑了刚性指数，连云港海相粘土的渗透系数在10~(-6)~10~(-8)cm/s量级，落水头渗透试验测得的水平渗透系数与CPTU测定的值吻合较好，说明在连云港海相粘土采用竖井排水时，在土体加固设计中应考虑涂抹效应对土体固结特性的影响。对于连云港海相粘土的加固方案，建议采用CPTU耗散试验确定的固结系数。
The coefficient of consolidation and coefficient of permeability of the Lianyungang marine clay are studied by laboratory and piezocone penetration test(CPTU) in order to evaluate the consolidation and permeability characteristics.The horizontal coefficient of consolidation ch of the clay is also back analyzed according to field data of monitored settlement.Comparisons of the results obtained by different methods indicate that the values of horizontal consolidation coefficients determined by CPTU are in the range of(3.0–6.5)×10-3 cm2/s,typically 2–4 times higher than those of vertical consolidation coefficients.The value of horizontal consolidation coefficient with back analysis is slightly lower than that deduced from CPTU based on Teh and Houlsby′s method.It could be possible due to the smear effect incurred during the installation of the vertical drains.For Lianyungang marine clay,it is recommended that Teh and Houlsby′s method,which takes the rigidity index into consideration,should be used.The coefficient of permeability of Lianyungang marine clay is in the order of 10-6–10-8 cm/s.The value of horizontal permeability coefficient measured by falling-head permeability tests agrees well with that determined by CPTU.It can be indicated when the vertical drains are used in Lianyungang marine clay,the smear effect on consolidation properties of soil has to be taken into consideration in the soil improvement design.For soil improvement schemes of the Lianyungang marine clay,the coefficient of consolidation determined by CPTU dissipation tests is recommended in practice.