Unsaturated Seepage Analysis of Cracked Soil including Development Process of Cracks

Ling Cao,Yong Chen,Zhijian Wang

doi:10.1155/2016/2684297

Abstract

Cracks in soil provide preferential pathways for water flow and their morphological parameters significantly affect the hydraulic conductivity of the soil. To study the hydraulic properties of cracks, the dynamic development of cracks in the expansive soil during drying and wetting has been measured in the laboratory. The test results enable the development of the relationships between the cracks morphological parameters and the water content. In this study, the fractal model has been used to predict the soil-water characteristic curve (SWCC) of the cracked soil, including the developmental process of the cracks. The cracked expansive soil has been considered as a crack-pore medium. A dual media flow model has been developed to simulate the seepage characteristics of the cracked expansive soil. The variations in pore water pressure at different part of the model are quite different due to the impact of the cracks. This study proves that seepage characteristics can be better predicted if the impact of cracks is taken into account.

Highlights

Cracked soils are common in nature, with expansive soils
The pathways provided by cracks significantly increase the hydraulic conductivity of the soil
The main objectives of this research are (1) to determine the mechanisms of crack initiation and development under natural conditions, (2) to develop a method to determine the soil-water characteristic curve (SWCC) of an unsaturated cracked soil, and (3) to use the SWCCs to analyze the unsaturated seepage based on a proper flow model

Summary

Introduction

Cracked soils are common in nature, with expansive soils. The cracks break the integrality of the soil, thereby reducing its strength. The pathways provided by cracks significantly increase the hydraulic conductivity of the soil. As such, it is easier for cracked soil slopes to slip or collapse during rainy seasons [1, 2]. In geotechnical engineering, much attention has been given to cracked soil seepage analysis [3, 4]. For slopes with cracks, it is necessary to determine the stability by including the effects of cracks when carrying out saturatedunsaturated seepage analysis. This has been done in previous studies [3,4,5,6]

Objectives

Methods

Conclusion