海水環境下におけるセメント処理した有明粘土の劣化の進行に関する検討

抄録

In construction, chemical soil stabilization method, such as adding cement and quick lime has been often applied to increase the strength of soft ground and surplus soil. However, in some specific natural environments, such a stabilization method may cause significant reduction of the strength of treated-soil. In this paper, Ordinary Portland cement was used as a stabilizer for examining the durability of chemical stabilized Ariake clay under seawater condition. In order to prepare deteriorated specimens, original Ariake clay was mixed with different contents of cement (50, 70, 100kg/m³) and immersing artificial seawater with different NaCl concentration (10, 20, 30g/L). The deterioration progress of cement-treated Ariake clay was investigated by using the micro cone penetration test. It is shown from the test results that the deterioration of cement-treated soil progresses in proportion to square root of seawater contacting duration. In addition, an empirical prediction formula of deterioration rate of cement-treated Ariake clay considering effect of Mg ion concentration in seawater and water-cement ratio in the treated soil is proposed according to experimental results.