RESIDUAL SHEAR STRENGTH CHARACTERISTICS OF LIQUEFACTION-AFFECTED SAND IN JONO OGE VILLAGE FOLLOWING THE 2018 CENTRAL SULAWESI EARTHQUAKE

The Mw 7.5 Central Sulawesi earthquake in 2018 triggered widespread liquefaction and severe ground deformation in Jono Oge Village, Indonesia.While liquefactioninduced damage has been extensively documented, quantitative experimental data describing post-liquefaction residual shear behavior of sands collected from affected sites remain limited.This study investigates the residual shear strength characteristics of liquefaction-affected sand using direct shear tests to represent large-deformation post-liquefaction conditions.Disturbed sand specimens collected from the Jono Oge area were reconstituted at relative densities of 20%, 35%, and 50% and tested under normal loads of 3, 6, and 9 kg, corresponding to shallow overburden stresses.Residual shear strength was identified from the post-peak shear response at large horizontal displacement.The test results show that liquefaction-affected sand exhibits pronounced strain-softening behavior followed by the development of a stable residual shear strength.Residual shear strength increases systematically with increasing normal load and exhibits an approximately linear relationship with normal stress.In addition, denser specimens mobilize higher residual shear resistance, indicating that particle packing continues to influence shear behavior even after liquefaction-induced