FIELD TEST STUDY ON THE CHANGES OF WATER, HEAT, SALT, STRESS AND THEIR MUTUAL INFLUENCE OF CFG PILE COMPOSITE FOUNDATION IN SALINE SOIL

摘要

The difference between salty soil and normal soil is that salty soil contains a certain amount of soluble salts, and these soluble salts can continuously migrate. Salt accumulation may cause the phenomenon of salt expansion or salt dissolution. On the other hand, the migration of salt will change the soil strength and the mechanical properties of pile-soil interface. In this paper, the test-section is set up in DK821 + 600 similar to DK821 + 900 of the new building Lanzhou-Xinjiang second double-lines railway, the variation of water, heat, salt, force and their mutual influence law of the CFG (Cement Fly-ash Gravel) pile composite foundation in saline soil are studied by field testing the temperature, the moisture content, the salinity content, the pile top stress, the soil stress among pile, the pile lateral soil pressure. It follows that the changes in temperature and groundwater level are the most important factors in the migration of salt, and the main factors leading to the salt migration at different depths in CFG pile composite foundation are not the same. The change in the pile top stress and the pile lateral soil pressure of the CFG pile composite foundation are little with the salt migration. Overall, the bearing capacity of CFG pile composite foundation is not sensitive to environmental factors.