Non-destructive technique for assessing cement-treated ground

A new, non-destructive technique for investigating the strength of cement-treated ground has been developed. The technique is based on the relationship between the unconfined compressive strength, q_u, and the shear wave velocity, V_s, of cement-treated soil. Based on the V_s–q_u relationship, the in situ strength of cement-treated ground can be estimated non-destructively and immediately by measuring the V_s value of the ground using bender elements in the field. To demonstrate the effectiveness of this technique, the ground at two actual construction sites was investigated using the technique. The variation coefficient of the measured V_s values ranged from 0·1 to 0·15, and was independent of the curing time and original soil type. The variation coefficient of the V_s values was smaller than that of the unconfined compressive strength estimated by conventional unconfined compression tests on specimens sampled from the same cement-treated ground. The quality estimated by the technique was consistent with the results of unconfined compression tests, indicating that the technique is a simple and useful means of inspecting the quality of cement-treated ground.