Prediction Study of Capillary Rise Height on Unsaturated Soil

Abstract

Based on the understanding of diseases of building’s foundation and manmade slope caused by water capillary rise, this thesis carried out a large number of laboratory tests by selfdeveloped absorption permeameter for unsaturated soil, in order to explore the capillary transport law of unsaturated soil. The thesis obtains some valuable results and conclusions: The moisture content shows minishing trend as the seepage fronts increasing, and reflects the gravitational potential of normal relations with the capillary action; (2) the water seepage frontal Hω% relation curve has no obvious inflection point, but the initial water content has an certain influence on the capillary moisture content distribution, the moisture content uses the initial moisture content of 12.5%, 9.8%, 8.0% and5.3% for testing showed an increasing trend at 4 cm and 16 cm sections, and the moisture content at the same section increased with the initial moisture content increasing, this reflects the rule that the smaller the moisture content is, the greater the matric potential, the water absorption capacity becomes stronger. (3)The moisture content difference between 4 cm and 16 cm of the initial moisture content is 12.5%, 9.8%, 8.0% and 9.8% is 1.48 %, 1.5 %, 1.7 % and 2.2 %, indicating that the smaller the initial moisture content is, the difference at the vertical section is greater. Finally, based on the relationship of Hω% curve, the thesis establishes the grey correlation prediction model, and forecasts the maximum capillary height of Lishi loess is 182cm.

Measurement and Simulation of Soil Water Contents in an Experimental Field in Delta Plain

“…This was because the long period of rainfall before had allowed the water table to rise significantly and then began to fall with evaporation, despite this small rain. At the same time, the soil water content of the deep layers remained relatively stable for capillary rise [56,57]. When the rainfall increased to 17.5 mm ( Figure 5c) and 30.8 mm (Figure 5d), the water table rose by 0.065 m (5.2%) and 0.360 m (31.0%), respectively.…”

“…High values of soil water content were observed at the deeper soil layers and strong correlation between soil water content and the water table were found at a depth of around 100 cm. The capillary action is significant in this region and the height of this capillary rise can be quite substantial [56,57]. Table 3.…”