Research on evaluation of sedimentation and consolidation properties of clay using RI-density log for dredging and reclamation

对某疏浚土进行了沉降柱试验。并在此基础上进行了恒速率固结柱试验。在这些试验中，同时进行了RI-密度测井，并测量了ρ t的深度剖面。然后对含水率范围较宽的粘土进行了弯曲单元试验和微型十字板剪切试验。根据试验结果，首先研究了RI-密度测井的可行性。在此基础上，求得了f为比容、σ v'为有效应力、w为含水量、w_L为液限、G为弹性剪切模量、s_u为抗剪强度的f-log σ v'、w/w_L-logG和w/w_L-log s_u的关系式。最后，将RI密度测井应用于封闭水体和围垦地的野外调查，并讨论了RI密度测井在该领域的适用性。主要结论如下：1. RI-密度测井在室内试验中的可行性是令人满意的。在清水、悬浮液、流体泥浆和床泥（底部沉积物）的每种状态下，密度都可以分别以高精度测量. f-log σ_v'关系可以通过测量密度和孔隙水压力得到。在w/w_L[约等于]1.5范围内，该关系可用一条直线近似表示，直线的斜率值与标准室内试验所得压缩指数C_c值几乎相等. w/w_L-logG关系可以近似为w/w_L[近似等于]1.5以内的直线。然而，倾角的值与C_c.4的值不同。w/w_L-log s_u关系可以用w/w_L[近似等于]1.5以内的直线近似。那么，倾角的值几乎等于C_c.5的值。验证了RI-密度测井在野外调查中的适用性。此外，提出了一种新的预测吹填地基沉降曲线的简单方法。

A series of settling column tests was carried out on a dredged clay. And continuously, constant rate of strain consolidation column tests were also conducted. During those tests, RI-density log was carried out simultaneously and in-depth profiles of ρ_t were measured. And then bender element tests and miniature vane shear tests were carried out for the clay with a wide range of water content. Based on test results, firstly, feasibility of RI-density log was investigated. Then, relations of f-log σ_v', w/w_L-logG and w/w_L-log s_u were evaluated, where f is specific volume, σ_v' is effective stress, w is water content, w_L is liquid limit, G is elastic shear modulus and s_u is shear strength. And finally, RI-density log was applied to field investigations in closed water body and reclaimed ground, and the adequateness of RI-density log for the investigations were discussed. Main conclusions are as follows.1. The feasibility of RI-density log in laboratory test is satisfactory. In each state of clear water, suspension, fluid mud, and bed mud (bottom sediment), the density can be measured with high accuracy, respectively.2. f-log σ_v' relation can be obtained by measurements of density and pore water pressure. The relation can be approximated by a straight line within w/w_L【approximately equal】1.5, and the value of the inclination of the line is almost equal to that of compression index C_c obtained from the standard laboratory test.3. w/w_L-logG relation can be approximated by a straight line within w/w_L【approximately equal】1.5. However, the value of the inclination differs from that of C_c.4. w/w_L-log s_u relation can be approximated by a straight line within w/w_L【approximately equal】1.5. Then, the value of the inclination is almost equal to that of C_c.5. The adequateness of RI-density log for field investigation is verified. Furthermore, a simple method to predict settlement curve of reclaimed ground was newly proposed.