Relation between settlement and cone penetration resistance at two sites

摘要

This paper gives a brief account of work at two sites attempting to correlate bserved settlements with CPT soundings. The idea that soil stiffness, for the prediction of settlement, is related to CPT resistance goes back some time; an important contribution coming from Schmertmann (1972) who proposed that the soil modulus at a given point in a sand profile is twice the cone penetration resistance. In this paper data from monitoring the settlement of two embankments, one a preload and the other permanent, are analysed. The soil at the preloaded site was of volcanic origin, at the other mainly recent sediments were encountered. The soil at the preloaded site was of volcanic origin, at the other mainly recent sediments were encountered. The results indicate that the relation between q_c and modulus for the volcanic soil is quite different from that for the recent sediments. For the sedimentary soil a factor of about 3 converts the net cone resistance to the constrained modulus, whereas for the volcanic soil the factor is about 12. These differences might be a function of the different fill thicknesses and consequently different levels of loading; the maximum fill thickness on the volcanic soil profile was about 3 m and at the sedimentary site it was up to about 10 m.