Experimental Research On The Improvement Of Cohesive Soils Based On The Surface-modified Principle

The processibility of cohesive soil with high water content is a familiar construction problem. For the water content is high, that kind of rubber-soil which cannot be easily compressed always appears under disturbance. It is hard to be dealt with during the construction. The expansive soil is also a kind of soil with troubles. Its great potential of changing its volume and the abundant quantity of rifts, along with the lower dry density, gives this soil a bad engineering quality. It is dangerous to certain project.Surface modification is a kind of chemical technique. It mainly adjusts the inner contradictory physical property of hydrophilic and hydrophobic character by utilizing surfactants. With this technique, the hydrophilic surface of cohesive soil minerals can be modified to be hydrophobic. In this dissertation, the idea of modifying the surfactant character of the soil particles to improve the engineering property of soil firstly was put forward based on the basic principle of surface modification. The idea was verified by sample experiments. Then two kinds of modifying materials was certified by experiments and proved to be perfect to solve the common engineering problems, such as the processibility and expansive character of cohesive soils. The results showed that the cohesive soil can be compressed to a much higher dry density with lower compaction energy at the same water content after modification, compared with the unimproved soil. Concerned with expansive soil, the selected modifying materials effectively constrained its strong potential of changing its volume. The modifying target is obtained. Meanwhile, the permeability and mechanical characteristics of the soil samples were tested and analyzed before and after modifications. A series of conclusions were obtained. According to the property of the modifying materials, the relative construction process was designed and simulated by numerical methods. And the relative parameters and conclusions were achieved as well.