Study On The Effect Of Plant Roots On The Intensity Of The Red Clay In Hainan

With the promulgation of the policy of international tourism island, the infrastructure construction and the ecological civilization development in Hainan Province have ushered in a new era of rapid development, so the vegetation slope, a new technology, which can not only protect the shallow surface of rock and soil slope but also restore the ecological environment, should be taken seriously in Hainan. This paper probes into the commonly used slope stability plants-bermudagrass root in Hainan Province and studies the cylindrical soil sample with roots based on Hainan red clay with the method of triaxial shear test. The following conclusions are drawn from this research:1. This paper describes a new method not only to obtain small-size cylindrical root-containing the triaxial soil samples, but also to keep the roots a natural distribution state in triaxial specimens;2. The analysis of the lab-grown bermudagrass roots showed that:①Bermudagrass root is fibrous; most of the roots are divergently vertical; the vertical angle of the root system is generally not more than45°;②The number of grass-roots under each bermudagrass (diameter d>0.1mm) is up to a maximum of21(generally in the range of8to12);③Bermudagrass root length is up to365.00mm, mainly concentrated in the0to250.00mm between the thickest diameter bermudagrass up to1.26mm, mainly concentrated in the range of0to0.90mm;④In the depth of0to20cm, as the depth of the soil layer increases, Bermudagrass root density gradually reduces;⑤Bermudagrass root tensile strength is in the range of23.44MPa to67.91MPa, and the average tensile strength is41.88MPa.3. Triaxial tests on the Hainan red clay showed that:①By means of triaxial consolidated undrained shear test on Hainan red clay soil sample, the root natural distribution containing root Hainan red clay sample, the conventional prepared containing the root Hainan red clay disturbed soil samples, the paper found that there are three different basic forms of the destruction of the sample;②The reinforcement effect coefficient range of natural distribution of roots on the red clay is1.33to3.56, correspondingly the intensity increased by33%to256%, and the reinforcement effect coefficient range of the artificial mixed roots on the red clay is1.24to3.27, correspondingly the intensity increased by24%to227%, compared with the artificial mixed roots on the red clay, the reinforcement effect of the natural growth of roots increased approximately by7.26%to8.87%, showing a tendency to increase with the confining pressure;③Presence of roots of herbaceous vegetation increases the shear strength of the soil mainly by increasing the c value. The coefficient of the red clay shear strength is c=21.82kPa,φ=13.14°, under the natural distribution, the shear strength for a strain of root sample with stem increased to around the value of△c=19.85kPa,△φ=1.04.