Rock analysis to characterize Saudi soft sandstone rock

Omar A Almisned,Naif B Alqahtani

doi:10.1007/s13202-021-01160-y

Abstract

As more engineering projects and activities are taking place on and around weak rocks, it is becoming more important to study and characterize them. Since regular practices of rock mechanical testing are not effective for weak rocks, special laboratory tests and measurements were performed to characterize the Alkharj Saudi weak sandstone rock which is a clastic rock dominantly sandy limestone and sandstone. Test results are presented in this paper. Porosity, permeability, and mechanical properties (stress, strain, Poisson's ratio, confined compressive strength and unconfined compressive strength) were obtained and then used to characterize the proposed weak rock. This paper provides a mean of classifying weak soft rocks despite encountered problems in handling and testing such materials.

Highlights

Soft rocks are the rock materials that have a strength between soils and hard rocks and do not crumble when immersed in water (Nickmann et al 2006; Kanji 2014b)
They are distinguished from hard rocks by their disintegration and irreversible loss of strength when being exposed to water and climate change within relatively short time
Definition of the range of unconfined compressive strength (UCS) of soft rocks varies among the experts

Summary

Introduction

Soft rocks are the rock materials that have a strength between soils and hard rocks and do not crumble when immersed in water (Nickmann et al 2006; Kanji 2014b). They are distinguished from hard rocks by their disintegration and irreversible loss of strength when being exposed to water and climate change within relatively short time. Coming across soft rocks in engineering projects are increasing, soft rocks characterization and mechanical testing are deficient in both information and confidence (Fernandes 2018). This deficiency leads to higher cost due to higher precautious safety factors. There are many criteria in the literature to distinguish between soft rocks and hard rocks, and to distinguish between soft rocks and soils

Methods

Results

Conclusion