Experimental Study on Compression Modulus of Sandy Soil

The compression modulus is a key parameter for evaluating compression behavior of soil layer and for predicting foundation settlement. Highpressure confined compression test and the standard penetration test were performed to investigate the compression characteristics of sandy soil layers beneath pile toe, and to obtain the relationship of compression modulus with depth and overburden pressure. The experimental results indicated that the compression modulus of sandy soil increased with pressure, but its increasing rate gradually reduced. The compression modulus almost linearly increased with embedded depth. The ratio of compression modulus under the pressure ranging from 100kPa to 200kPa to that under the pressure in the range of overburden pressure to the additional stress plus overburden pressure (Es/Es0.1-0.2) ranged from 2.1 to 4.2. The empirical formula of the Es/Es0.1 -0.2 ratio with overburden pressure was established to give a reference to predict compression modulus of sandy soil under actual pressure, as its overburden pressure was known. At last, the basic principles of how to determinate the value of compression modulus were proposed for design of pile foundation.