Pengaruh Fraksi Lempung Terhadap Nilai Kohesi dan Indeks Plastisitas

Renold Pangidoan Rambe, Lusmeilia Afriani, Iswan Iswan


This study aims to see the influence the fraction of clay in the sand by comparing parameters of
strong shear soil that is resulted from unsoaked and soaked conditions of Direct Shear Test and
Atterberg Limit. An increase in the fraction of clay in the sand can change the physical properties
of the soil and the mechanical properties. An increase in the fraction of clay can also improve the
value soil cohesion and ground plasticity index but it reduces the value soil friction. The
parameter change magnitude is analyzed by looking at the results of correlation analysis of
cohesion of the soil plasticity index, and some of the physical parameters of the soil. The
correlation between the shear test directly with the plasticity index against the physical properties
of soil clays that linear regression obtained a very strong correlation (0.8 – 1) and limit land that
is used are sand which is already substituted by clays from 0% – 50%.
Direct shear test which results from the condition of unsoaked conducted in the laboratory
obtained that addition levels of clay showed an increase in the value of cohesion but the angle
shear declined. Direct shear test results from the condition of soaked (soaking 4 days) obtained a
decrease of the value of cohesion (c) down and slide angle (φ) which is also affected by soaking
the soil. The test results show the Atterberg limits that a percentage of the original soil and
addition of clays to 20% has no plasticity index value. This is because the ground is still are off
(loose soil). As for the addition of clays from the percentage of 30%, 40%, and 50% of the land is
included soil cohesive and value each PI is 8.87%, 17.7%, and 12.04%.
Keywords: direct shear, cohesion, plasticity index

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Department of Civil Engineering

Engineering Faculty

University of Lampung


Copyright (c) JRSDD (Jurnal Rekayasa Sipil dan Desain)
P-ISSN: 2303-0011 (Print); E-ISSN: 2715-0690 (Online)