Identifikasi Karakteristik Teknik Subgrade Jalan (Studi Kasus Jalan Raya Tanak Awu-Pengembur, Lombok Tengah)
Authors: Pujiastuti Heni , Fitrayudha Adryan , Fariyadin Adiman , Hamdani Hafiz 
Published: January 2024

Abstrak
 
Jalan yang menghubungkan Desa Tanak Awu menuju Desa Pengembur yang berada di Kecamatan Pujut, Lombok Tengah, sering rusak, retak-retak dan bergelombang. Tujuan penelitian ini adalah memaparkan hasil identifikasi karakteristik teknik subgrade Jalan Tanak Awu-Pengembur, meliputi karakteristik fisik, mineralogi, karakteristik hidromekanik dan karakteristik mekanik, berdasarkan hasil uji eksperimen di laboratorium agar dapat menjadi masukan bagi institusi terkait. Hasil identifikasi mineralogi dan karakteristik fisik menyimpulkan bahwa subgrade Jalan Tanak Awu-Pengembur merupakan tanah ekspansif. Hasil identifikasi mekanik menyatakan Nilai California Bearing Ratio (CBR) rendaman desain tanah sampel sebesar 2 % telah memenuhi persyaratan minimum sebagai subgrade jalan, namun untuk subgrade tanah ekspansif, nilai CBR perlu ditingkatkan menjadi lebih besar dari 6 % dengan perbaikan tanah dasar dapat berupa stabilisasi semen atau material timbunan pilihan dengan tebal minimum 600 mm (MDP 2017). Hasil uji CBR dengan variasi kadar air kondisi jenuh dan jenuh sebagian,  pada bagian awal kurva sampai pada nilai Air Entry Value (AEV)  peningkatan nilai CBR tanah terhadap matric suction berbentuk linier, selanjutnya pada kenaikan  matric suction antara 600 kPa-2400 kPa, terlihat nilai CBR tanah mulai meningkat signifikan, peningkatan matric suction yang lebih tinggi (antara 2400 kPa-20000 kPa), peningkatan nilai CBR terhadap matric suction lebih landai.
 
 
Abstract
 
The purpose of this research is to describe the results of the identification of the technical characteristics of the Tanak Awu-Pengembur Road subgrade, including physical characteristics, mineralogy, hydromechanical characteristics, and mechanical characteristics, based on the results of experimental tests in the laboratory so that they can be input for related institutions. The results of mineralogy and physical characteristics identifications concluded that the subgrade of Jalan Tanak Awu-Pengembur is an expansive soil. The results of mechanical identification stated that the design value of the California Bearing Ratio (CBR) soaked soil sample was 2%.  The design value of CBR soaked has met the minimum requirements as a road subgrade. However, for expansive soil subgrades, the CBR value needs to be increased to greater than 6% with subgrade improvement in the form of cement stabilization or embankment material of choice with a minimum thickness of 600 mm (MDP 2017). The results of the CBR test with variations in water content in saturated and unsaturated conditions, at the beginning of the curve  the increase in the CBR value of the soil to matric suction is linear. The results of the CBR test with variations in water content in saturated and unsaturated conditions, at the beginning of the curve the increase in the CBR value for matric suction is linear, furthermore, at an increase in matric suction between 600 kPa-2400 kPa, the CBR value begins to increase significantly, the increase in matric suction is higher (between 2400 kPa-20000 kPa), the increase in the CBR value to the matric suction is more ramps.