Undrained Shear Strength c_uand Undrained Elastic Modulus Eu of Anthropogenic Soils from Laboratory Tests

Abstract

Undrained shear strength cu and undrained elasticity modulus Eu are one of the basic mechanical parameters describing soil properties in engineering practice. In a simple way cu can be established by fall cone test or, similar as the Eu modulus, can be determined from the stress-strain curve obtained from the uniaxial or triaxial compression tests. The paper presents the results of laboratory tests od cu and Eu parameters carried out on anthropogenic soil in uniaxial compression tests and fall cone tests. The soil used in the study represented different types of materials used in earthworks - containing different share of clay fraction. Tests were provided on the soil in different bulk density and water contents. The paper proposes a method of estimating Eu50 on the basis of cone penetrometer tests. Such test does not require any additional preparation and can be performed directly on the soil compacted in the cylinder of the Proctor’s apparatus, which allows for a quick assessment of the soil elasticity parameters.

Hydrogeotechnical Predictive Approach for Rockfall Mountain Hazard Using Elastic Modulus and Peak Shear Stress at Soil–Rock Interface in Dry and Wet Phases at KKH Pakistan

“…The substantial collapse of the PS and ES causes the triggering of rockfall. The critica The developed equations (correlations) in the present study have been compared with the literature, and a resemblance of the drop in the shear stress and elastic modulus was observed when compared with the study of [54], which presents a substantial drop in the shear stress and elastic modulus from 15% to 23% moisture content, validating the data of present study; however, the difference in values is attributed to the difference in material properties.…”

“…The following correlations of moisture content (MC) with the peak shear stress (PS) (Equations ( 1) and ( 2)) and elastic modulus (ES) (Equations ( 3) and ( 4)) are developed (Figures 7 and 8) at the matrix density ranging from 1.78 g/cm 3 to 1.92 g/cm 3 (equivalent to field density) for the soil-soil (Equations ( 1) and ( 3)) and soil-rock interfaces (Equations ( 2) and ( 4 The developed equations (correlations) in the present study have been compared the literature, and a resemblance of the drop in the shear stress and elastic modulus w served when compared with the study of [54], which presents a substantial drop in the stress and elastic modulus from 15% to 23% moisture content, validating the data of p study; however, the difference in values is attributed to the difference in material prope…”

“…The correlations of the PS and ES are high in the dry phase due to the bonding of the clay fraction (cohesive material) with the sand fraction (non-cohesive material). Clay shows high bonding strength in its dry condition and depicts collapsing behavior in its wet condition [54]. Typical stress-strain curves are presented in Figure 6 for the soil matrix.…”

“…The correlations of the P S and E S are high in the dry phase due to the bonding of the clay fraction (cohesive material) with the sand fraction (non-cohesive material). Clay shows high bonding strength in its dry condition and depicts collapsing behavior in its wet condition [54]. The following correlations of moisture content (MC) with the peak shear stress (PS) (Equations ( 1) and ( 2)) and elastic modulus (ES) (Equations ( 3) and ( 4)) are developed (Figures 7 and 8) at the matrix density ranging from 1.78 g/cm 3 to 1.92 g/cm 3 (equivalent to field density) for the soil-soil (Equations ( 1) and ( 3)) and soil-rock interfaces (Equations ( 2) and ( 4)): The following correlations of moisture content (MC) with the peak shear stress (P S ) (Equations ( 1) and ( 2)) and elastic modulus (E S ) (Equations ( 3) and ( 4)) are developed (Figures 7 and 8) at the matrix density ranging from 1.78 g/cm 3 to 1.92 g/cm 3 (equivalent to field density) for the soil-soil (Equations ( 1) and ( 3)) and soil-rock interfaces (Equations ( 2) and ( 4)):…”