Scale effect of moisture migration on bi-layer gradient composite material   Zheng-ming XU State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei, 430071 e-mail: mail_xzm1986@163.com Qiang XUE State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei, 430071 Ying ZHAO State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei, 430071
			ABSTRACT

Bare slopes are ecologically protected by bi-layer gradient composite material (GCM) which is made by modified sludge and straw fibers. It has two layers of permeability formation and water reservoir bed. For one thing, it can effectively provide moisture need by vegetation growth. On the other hand, it can avoid phenomena of erosion in slope gully area under precipitation. A partial differential equation to simulate one-dimensional moisture migration in bi-layer GCM is established, the corresponding numerical simulation carried out. Moisture dynamic migration law of GCM was analyzed under multi material scale conditions. The numerical results show that moisture storage velocity and capacity are lager when thickness of seepage layer is 5cm with 10cm reservoir bed. Moisture content growth amplitude of bigger reservoir bed GCM presents uniformity variations after 5hr moisture migration. However, due to infiltration capacity, moisture content growth amplitude of less 5cm reservoir bed GCM gradually decreases, up to steady value. Therefore, numerical simulation results provide theoretical basis for dynamical regulate of permeation and water storage and moisture migration in composite material or rock mass medium. It simultaneously offers reliable basis for field ecological shelter and repair of high steep slope.

Keywords: Gradient composite material; Moisture migration; Scale effect; Matrix suction hydraulic head.

Get the entire paper (pdf)     Go back to the TOC