Rock mass classification and rock mass slope failures along Bang Pa-In to Nakhon Ratchasima intercity motorway (M6) Project, Thailand

Abstract

This research intends to use the Rock Mass Rating (RMR) and the Slope Mass Rating (SMR) systems to evaluate the rock mass classes of the road cut slope in the construction of the Bang Pa-In-Nakhon Ratchasima intercity motorway (M6) project, sections 19, 20, and 21. The study area consists of a mountain and plain landform with limestone, sandstone interbedded with shale, and structural control. Drill and blast techniques were utilized to excavate and develop the slope face as well. Kinematic analysis was also used to classify potential slope failure and estimate the adjustment factors. The result found that three sections of the study area have the potential failures of the wedge, toppling, and planar. In section 19, the SMR class is normal to good and stable to a partial stable of slope that is a failure with toppling and wedge on the right and wedge on the left side. Section 20 is normal and partially slope stable, with three types of failure on the left side, but a wedge and toppling on the right side. Section 21 is a good class, and the slope is stable, but slightly wedged and toppling failure on some blocks on the right side and only wedged on the left site as indicated.