Engineering Geological Evaluation on Expansive Soil Controlling the Instability of Road Construction in Karangjati-Pakulan, Ngawi Regency, East Java
| Main Authors: | , SOPHEAP POR, , Prof. Ir. Dwikorita Karnawati, M.Sc., Ph.D., |
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| Format: | Thesis NonPeerReviewed |
| Terbitan: |
[Yogyakarta] : Universitas Gadjah Mada
, 2012
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| Subjects: | |
| Online Access: |
https://repository.ugm.ac.id/100972/ http://etd.ugm.ac.id/index.php?mod=penelitian_detail&sub=PenelitianDetail&act=view&typ=html&buku_id=57518 |
Daftar Isi:
- Indonesia is a country that located in Southeast Asia. Most part of this country consists of expansive soil, for instance roads in Karangjati-Pakulan, Ngawi Regency, East Java, which constructed over expansive soil. The domain problems in this research area are geological and geotechnical condition. This area mainly consist type of expansive soil that cause of cracking, deformation, and settlement on roadway foundation and their structure that occurs due to its highly swelling (in rainy season) and shrinkage (in dry season). The main objectives of this research are to investigate the engineering geological, geotechnical and hydrogeological conditions that controlling the swelling and shrinkage of expansive soil, to understand the cause and mechanism of swelling and shrinkage including their mineral identify of expansive soil based on engineering geological, geotechnical, and hydrogeological consideration. The methodologies of the research were conducted by field investigation and laboratory analysis that focused on geomorphology, geological, geotechnical, hydrogeological, and road damage condition. Soil analysis of the engineering properties were soil index properties, Atterberg Limits, sieve analysis, swelling test, direct shear test, triaxial test, differential free swell test, swelling ratio test, and also including their mineral content analysis (XRD) were conducted. As the result, geomorphology in the study area were divided in to three main parts namely steep hill slop (>ï� ̄15), gentle hill slop (ï� ̄155ï�), and flat plain or alluvial area (<ï� ̄5). The alluvial area consists of clay and silty-clay 86-96% in the depth of 0-3.5 m, with the liquid limit (LL) 74.70-93.98%, plasticity limit (PL) 26.49-32.4%, plasticity index (PI) 47.94-68.18%, shrinkage limit (SL) 9.08-11.49%. Moreover, the XRD analysis result showed that the clay mineral in the alluvial area is the type of montmorillonite clay that has it origin from the weathering process of lithology at the upper hill transported by rain water combined with the residual soil. The groundwater fluctuation in the flat plain is 0.2-3m in rainy season (cause of swelling) and 2.8-5 m in dry season (cause of shrinkage). The swelling pressures of clay are high to very high, started from 296.97 kPa to 1239.54 kPa. Based on these engineering properties, it is concluded that the expansive soil in the study area is high to very high potential of expansive. Due to the time of this research is limited, for the suggestion, soil replacement before the construction started by nonexpansive soil at the shallow depth and the provision of appropriate drainage system are required to minimize the swelling and shrinkage of expansive soil in the study area.