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A systematic correlation is established between the axial load-carrying capacity of the socketed piles and empirical methods. The axial load-carrying capabilities were calculated with the help of pile load tests for ten single piles in Navi Mumbai, India. Pile load tests were carried out to evaluate the skin friction and base resistance in overlying soil and rock. The test results of axially loaded bored piles socketed into the rock are mentioned in this paper. The pile socket involved rocks of various strengths such as gypsum, limestone, and basalt. In reality, axial capacity is calculated from skin friction of the pile, which occurs owing to a very small settlement in the rock socket. The unconfined compressive strength of the rock is collected from the laboratory test. The load-bearing capability of the socketed piles is determined using several empirical methods, which are usually evaluated by a back-assessment of the in-situ pile load test. However, the significant load-carrying capacity values derived from empirical correlations are found to be reasonably good compared with those estimated from pile load tests. [ABSTRACT FROM AUTHOR]

Sustainable development goal 6: clean water and sanitation—could be a big challenge for water-stressed India. Use of non-potable water for concrete production can contribute largely towards this goal. Scattered experimental studies on concrete mixed with non-potable water having different pH, were collated to prepare a pan-Indian database. Using this data, probability of code compliance of Indian concrete for varying ranges of pH value of mixing water, within the limits permitted by the Indian code (6–8.5), were estimated for the first time in India. A bootstrap-based re-sampling approach was employed for this purpose. The results indicated that fulfilling the 28-day strength requirements would possibly concurrently fulfill similar stipulations for 7-day strength for Indian concrete mixed with non-potable water of varying pH. However, the probabilities of meeting the Indian code requirements were between 54%-66% for pH ranges starting from 6; and between 66%-85% for others (95% confidence). Considering the entire range of pH (6–8.5), this probability was 66% for 28-day and 72% for 7-day (95% confidence). Probabilistic approach for examining the strength/setting time compliance, along with inclusion of 7-day strength as well as durability aspects in future experiments would help to promote use of non-potable sources of water and reduce use of freshwater for mixing concrete in India. [ABSTRACT FROM AUTHOR]

The July 12, 2016 Tombinoutek landslide along state highway between Imphal and Jouzangtek village, Manipur, India affected the road section for a stretch of ∼475 m. The research aimed at finding the combined effects of topography, lithology and structural attributes of the landslide. Detailed geodetic survey was carried out using drone supported by ground control points obtained by total station survey. Base map with 5 m contour intervals, slope and aspect maps prepared; critical slope is between 45° to 60°. Geological studies have shown occurrence of intercalated sandstones and dissected shale, disturbed by five prominent joint sets which play an active role in the initiation of the landslide through plane and wedge failures. Geotechnical analyses of sandstones indicated strong compressive strength ranging between 80 and 97 Mpa, and tensile strength of sandstones and shales between 17 and 20 Mpa and 2.62 and 3.27 Mpa respectively. Soil analyses showed plasticity index (IP, percentage) of 10.66, and liquid limit (WL%) of 32.5. Average soil porosity is 80%. Liquidity index of -1.208 indicates relatively stable condition under dry condition. Plasticity index of 10.66 lies in the CL field, close to the boundary between low plasticity and medium plasticity. Sandstones show fair rock RMR with class IIb stable SMR, and shales show poor rock RMR with class IIIb partially stable SMR. [ABSTRACT FROM AUTHOR]

Evidence of frictional melting in the form of pseudotachylite is innumerably found along the Gangavalli fault zone (GFZ), southern India. Such catastrophic deformation influences the strength of rock masses across the fault zone. In this paper, we have investigated the strength variation in fault zone rocks during post-seismic deformation. The experimental study suggests that the average uniaxial compressive strength (UCS) for pseudotachylite hosting charnockite (i.e., Pt-charnockite) is almost double (45.58 MPa) as compared to the pseudotachylite devoid charnockite (i.e., D-charnockite) of 24 MPa. The melt associate seismic deformation shows high stress drop due to melt lubrication at the fault interface and simultaneously produced numerous fractures in the rock. We have determined the stability and denseness of both rock types using acoustic emission (AE) technique that remarks a distinct difference in AE signatures. The analysis indicates a more stable and dense Mogi type-III signature for post-seismic deformed rocks that are assisted by pseudotachylite melt. However, negligible AE energy is observed in the D-charnockite. We proposed that the melt-assisted seismic deformations are more inhibitable to reactivate the slip surfaces than the conventional earthquake-deformed rock having no melting phenomenon and therefore, pseudotachylites enhance the strength of fault zone rocks during post-seismic deformation. [ABSTRACT FROM AUTHOR]

The study considers the impact of the degree of weathered material constituting the sedimentary rocks on the strength of the Lower Gondwana coal measure rocks. The dependence of the strength of primary rocks on the alteration indices has been previously studied, but it is unknown for secondary/sedimentary rocks. Therefore, in this paper, Lower Gondwana coal measure rocks (sandstone and shale) from the most productive coalfields of India, the Barakar and Raniganj coalfields, have been studied geochemically and geomechanically to find out their correlation. Geochemically, the study revealed that an arid, non-marine, and deltaic depositional environment prevailed during the sedimentation of Barakar and Raniganj Formations. The provenance was deduced to be mafic igneous. It was also deduced that the Lower Gondwana sandstone is clay-rich, and the sandstone samples fall in the shale field in the chemical classification scheme for terrigenous clastic sediments. The weathering indices, along with the uniaxial compressive strength (UCS) of the Barakar and Raniganj Formation coal measure rocks, have been assessed. The dependence of UCS on the weathering indices has been evaluated, and positive relationships were obtained. [ABSTRACT FROM AUTHOR]