Reinforcement Effect Arising From Confining Dilatancy by Geosynthetics

Geotechnical Predictions and Practice in Dealing with Geohazards

“…The reinforcement effect produced by the use of geosynthetics is not a simple aggregate of the rigidity and strength of both geosynthetics and compacted soil. Assuming that the dynamic interactions between geosynthetics and compacted soil are the effects arising from geosynthetics restraining the dilatancy of compacted soil under shear, the authors conducted finite-element simulations of full-scale field tests (Hirata et al 1999) and model tests (Iizuka et al 2001). Consequently, the effect of geosynthetics-reinforcement is generally higher than expected and therefore quite reliable when used against earthquakes and other geohazards.…”

“…The Kamihikawa Dam analyzed in this study is an 87-m high, 94-m long centercore rockfill dam with a volume of 4,110,000 m 3 (Ohta et al 2001;Mori et al 2001). The embankment and reservoir filling process of a rockfill dam is reproduced by FEM, and the stress-deformation behavior of the core zone is traced with the aim of estimating the possibility of the occurrence of a hydraulically weak area and the initiation of hydraulic fracturing.…”

“…The Kamihikawa Dam analyzed in this study is an 87-m high, 94-m long centercore rockfill dam with a volume of 4,110,000 m 3 (Ohta et al 2001;Mori et al 2001). Other details of the dam, including construction method, physical or mechanical properties, and the embankment and filling reservoir process are detailed in the references (Ohta et al 2001;Mori et al 2001). Figure 9.2 shows a typical cross-section of the dam.…”

“…The authors have reported that the stress-deformation behavior of large rockfill dams during construction and first reservoir filling can be evaluated accurately enough using soil-water coupled elasto-plastic analysis (Ohta et al 2001;Mori et al 2001) and stability against hydraulic fracturing can be quantified by using the minor principal stress and pore water pressure thus computed (Ohta et al 2005 This chapter provides an overview of the evaluation method for the stability of large rockfill dams against hydraulic fracturing. The failure of a large rockfill dam is one of the most tragic geohazards.…”

Numerical Simulation of Soil Structures Reinforced by Geosynthetics

“…Their field tests revealed that geosynthetics and compacted soil behave as an integrated body. Assuming that the dynamic interactions between geosynthetics and compacted soil are the effects arising from geosynthetics restraining the dilatancy of compacted soil under shear, the authors conducted finite-element simulations of full-scale field tests (Hirata et al 1999) and model tests (Iizuka et al 2001). This chapter presents elasto-plastic constitutive models with the dilatancy of compacted soil under shear taken into consideration and an estimation method for constitutive properties of compacted soil.…”