Zhang Ke-neng

Retention of clay-solidified grouting curtain to Cd2+, Pb2+ and Hg2+ in landfill of municipal solid waste

The effects of components and their ratio of groups on anti-seepage capability of clay-solidified grouting curtain and its permeability of heavy metal cations were investigated by permeating experiments, using reactive solute transport model to study the permeation of heavy metals (Cd2+, Pb2+ and Hg2+). The study of permeating for different mixture ratios of cement and clay indicates that hydraulic conductivity of clay-solidified groupting curtain with different ratios of solid to liquid or with the same ratio of solid to liquid but with different ratios of cement to clay is changed. The laboratory simulation test results also show that precipitates produced in heavy metal cation migration process in curtain block up water flowing passage which makes the hydraulic conductivity of the solution-permeated curtain decrease with the leakage time. The permeation velocities for different heavy metal cations vary with ionic concentration, exchange capacity and ion radius etc. The test results indicate that the permeation rapidity order of heavy metals cations in clay-solidified grouting curtain is Hg2+ > Pb2+ in the same experimental circumstance. In addition, permeability for different mixture ratios and antisepsis capabilities of clay-solidified grouting curtain were studied in tests.

Process stability of high cut slope under complex geological conditions during construction

A typical soil similar slope with abundant Quaternary groundwater is located in Chenzhou City, China and mainly composed of gray-white silt clay which softens in water. The landslide occurred during the first evaluation in the ratio of 1∶1.25, and then twice during the following reinforcement in the ratio of 1∶3. As a result, the scale of the landslide enlarged 20 times and the slope was still in low deformation. Based on the engineering geological conditions, the landslide character and the monitoring data, the evaluation model of slopes process stability was built by use of FEM, which simulated the course of the landslides. And then, the landslide mechanism was analyzed and key points of the following construction process control were put forward. The result shows Process stability of high cutting slope under complex geological conditions during the construction is a controllable procedure variable, lacking effective control is the main reason for the landslide. The method, consist of FEM simulation and monitoring is effective in researching slopes process stability during construction and the mechanism of landslide, meanwhile it also provided dynamic guidance for the excavation and reinforcement.