| The phenomenon of capillary water rising can be easily found in loess, thus affecting the moisture content, strength, soluble salt content, and microstructure of the soil. Consequently, soil stability will be reduced and loess foundation weaken. This paper focuses on the behavior of capillary water rising and moisture content changing in loess and modified loess under different rates of lime and cement adding, in order to deduce height and velocity of capillary water as well as density, dry density, unconfined compressive strength, content and category of soluble salt, specific surface area (SSA), cation exchange capacity (CEC) and microstructure after 50 days of capillary water rising. The study also estimates the feasibility of using lime and cement to resist influence of capillary water rising and makes comparison of the modifiers. In the test, loess was modified by three methods:3% lime adding,5% lime adding and 3% cement adding according to lime weight. Conclusion can be shown as follows:all of the three can effectively slow down height and velocity of capillary water (from 160 cm in loess to a low of merely approximately 60 cm), improve strength (after 50 days, unconfined compressive strength of cement modified loess at the soil-water interface was 0.86MPa,3 times of that in loess sample), restrain migration of soluble salt in sample. Meanwhile, lime and cement create a large amount of hydration products which fill the tiny voids, parcel and connect loess particles into bigger ones. Under the effects of capillary water rising, soil particles can maintain face-to-face contact pattern and soil still have net structure, what’s more, the hydration gel prevent capillary water from continuous rising. Last but not least, lime has the better impact on moisture content reducing while cement contributes more to soil inner structure improvement. Additionally, cement has greater effects to strength, water stability as well as capillary water rising obstacle in loess. |
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