Integrative Analysis of Surface Runoff and Macropore Flow for Slopes under Rainfall Conditions

Yun Que,Denghui Lin,Peiyuan Lin

doi:10.1155/2018/9458410

Abstract

Estimating runoff and infiltration in slopes is essential to predict flooding and landslide triggering. An approach jointly using a dual-permeability model and a kinematic wave model was proposed for integrative analyses of infiltration and surface runoff of rainwater for slopes with macropores in soils subjected to rainfalls. Laboratory tests were conducted to evaluate the performance of the proposed approach. Analyses showed that the presence of macropores greatly facilitates rainwater movement in the slope and the maximum depth of wetting front could be one order of magnitude larger than in cases without macropores. The influence of rainfall intensity, initial pore water pressure, coefficient of permeability of soil matrix, and slope angle was also examined.

Highlights

Slope stability failures due to short-duration high-intensity rainfalls such as seasonal typhoons and rainstorms are not uncommon in coastal areas of southeastern China
When a slope is subjected to a rainfall event, at early stage the rainwater is absorbed by soils at and near the slope surface because of their high infiltration capacity at dry conditions
Slope surface runoff takes place and the infiltration rate is equal to the infiltration capacity of the surface soils under saturated conditions

Summary

Introduction

When a slope is subjected to a rainfall event, at early stage the rainwater is absorbed by soils at and near the slope surface because of their high infiltration capacity at dry conditions. At this stage, the infiltration rate is equal to the rainfall intensity. Slope surface runoff takes place and the infiltration rate is equal to the infiltration capacity of the surface soils under saturated conditions. Models have been developed to describe this rainfall-infiltration-runoff process for slopes where the infiltration capacity of soils across a slope is more or less similar; for example, differences in coefficient of permeability are usually within one order of magnitude [7,8,9,10]

Methods

Results

Conclusion