Analisis Stabilitas Lereng dengan Perkuatan Geocell Menggunakan Metode Elemen Hingga (PLAXIS 2D)

ABSTRAKLereng adalah permukaan bumi yang membentuk sudut kemiringan tertentu dengan bidang horizontal. Salah satu tindakan penanganan bencana longsor pada lereng melakukan perkuatan lereng menggunakan bahan geosintetik seperti geocell. Penelitian ini bertujuan untuk menganalisis pengaruh geocell terhadap kestabilan lereng, sehingga dapat diketahui karakteristik pemasangan geocell yang dapat meningkatkan faktor keamanan suatu lereng. Penelitian ini melakukan variasi jarak antar vertikal geocell dengan spesifikasi geocell dan data tanah yang telah didapatkan untuk dilakukannya tahap pemodelan dengan perkuatan geocell sampai mendapatkan nilai faktor keamanan lebih besar dari nilai faktor keamanan minimum. Pemodelan dilakukan menggunakan program PLAXIS 2D. Perkuatan dengan geocell efektif digunakan pada tanah lempung, sehingga pemasangan jarak vertikal geocell yang paling efektif terdapat pada jarak 1 meter berdasarkan panjang geocell 6 m, dengan kemiringan lereng 1:1, kuat tarik 14,5 MPa dan didapatkan nilai SF lebih besar dari /batas minimum, semakin rapat pemasangan geocell mampu meningkatkan nilai faktor keamanan dengan rata-rata sebesar 7%.Kata kunci: faktor keamanan, geocell, stabilitas lereng, timbunanABSTRACTSlope is the surface of the earth that forms a certain angle of inclination with a horizontal plane. One of the prevention to overcome landslides on slopes is to strengthen slopes using geosynthetic materials such as Geocells. This study aims to analyze the effect of geocells on slope stability, so that the characteristics of geocell installation can be known which can increase the safety factor of a slope. This study varies the distance between vertical geocells with geocell specifications and soil data that has been obtained for the modeling phase with geocell reinforcement to obtain the safety factor value greater than the minimum safety factor value. Modeling is done using 2D PLAXIS program. Reinforcement with geocells is effectively used on clay soils, so that the most effective vertical geocell spacing is at a distance of 1 meter based on the geocell length of 6 m, with a slope of 1: 1, tensile strength 14.5 MPa and the SF value is greater than / minimum limit, the denser the geocell installation can increase the value of the safety factor by an average of 7%.Keywords: safety factor, geocell, slope stability, embankment

Effect of infill materials on vibration isolation efficacy of geocell-reinforced soil beds

This paper investigates the isolation efficacy of geocell-reinforced foundation beds infilled with different materials through a series of block resonance tests. The geocell made with a novel polymeric alloy (NPA) was used in the experimental investigation. In total, five different cases — namely, unreinforced, geocell-reinforced silty sand, geocell-reinforced sand, geocell-reinforced slag, and geocell-reinforced aggregate — were considered. Presence of the geocell has resulted in improvement of screening efficacy of the foundation bed regardless of the infill material. The displacement amplitude of the geocell-reinforced bed cases was reduced by 68%, 64%, 61%, and 59%, respectively, for aggregate, slag, sand, and silty sand infill cases as compared to the unreinforced condition. Maximum isolation efficiency was observed in the presence of aggregate, among the four different infill materials. In the presence of aggregate infill, the shear modulus of the foundation bed was improved by 150%. Similarly, the peak particle velocity and peak acceleration were reduced by 57% and 48%, respectively. Further, the efficacy of mass spring dashpot (MSD) analogy was studied in predicting the frequency–displacement response of different reinforced cases. From the analytical study, a significant improvement in damping ratio of the foundation bed was observed in the presence of geocell reinforcement.

THE EFFECT OF SOIL GRAIN SIZE ON THE DEFORMATION PROPERTIES OF REINFORCED GEOCELL LAYERS

The effect of backfill material grading on the behaviour of geocell reinforced layers was experimentally investigated in this study. A series of loading tests were performed on a model with geocell reinforced and unreinforced layers. Five types of crushed aggregates were used as backfill materials in the experiment. The results showed that geocell reinforcement increased the deformation parameters. The rate of increase of the deformation characteristics depended on the backfill material grading.