Shear characteristics on soil specimen including roots of Festuca arundinacea Schreb. and Festuca longifolia Thuill. with taking notice of the difference of slope directions

Abstract

Direct shear tests on soil specimens including roots of Festuca arundinacea Schreb. and Festuca longifolia Thuill. were conducted based on the soil dressing seed spraying Engineering. Water contents in soil specimens were different with the difference of slope directions, and this had influences both on cohesion, c and on angle of shear resistance, φ. When the soil specimen included the roots of two exotic herbaceous plants, the c values only increased. In addition, the c value indicated a maximum at the flatland. The c values of F. arundinacea were larger than that of F. longifolia with good growing condition. Not only the increment Δc of c value with the roots in soil specimens but also the value divided c value by root length density were almost same with any slope direction in two plants.