Field tests of full-scale screw micropiles with a diameter varying from 76 to 114 mm and a length varying from 1.6 to 3 m were undertaken to investigate the axial pile capacities, load-transfer mechanism, and end installation torques of the piles in cohesive soils. Forty tests were performed on piles subjected to axial compressive and tensile loads. Six tests were instrumented with strain gauges on the pile shaft. Results showed the piles reached the limit state before the displacement exceeded 10% of the shaft diameter. The majority of axial load was transferred to the threaded segment. The adhesion coefficient of the top smooth shaft at the limit state was less than 0.1. The failure mode along the cylindrical threaded shaft was cylindrical shearing along the edge of the threads; the threads increased the axial capacities of the segment. Axial capacities of the threaded tapered segment were 43% on average greater than that of a cylindrical segment with the equivalent volume. Compressive capacities of all test piles were estimated and the results agreed reasonably well with the measured capacities. A theoretical torque model was proposed to estimate the end installation torques based on the cone penetration test results; the theoretical results matched the measured end torques very well.

An earthquake of moment magnitude M_w 7.8 struck Nepal at 06:11 UTC on April 25, 2015. Field reconnaissance focused on the geotechnical engineering aspect of the earthquake was carried out in the Kathmandu Valley and regions near the epicenter. This paper presents briefly the geology of Nepal, the accelerogram, and results of standard penetration tests at selected sites in the valley. The study shows the failure case histories including landslides, road embankment settlement, bridge foundations and abutment damage, and liquefaction. The paper also highlights the impact of local soil properties and basin and ridge effect on the severity of damage.

The Gorkha (Nepal) earthquake of the moment magnitude M _w 7.8 occurred on 25 April 2015, with the epicenter 77 km north-west of Kathmandu at a focal depth of 13 km. After the main shock of the earthquake, a field investigation was carried out in the Kathmandu Valley to collect case histories of geotechnical and structural damages. This paper provides the observations of liquefaction case histories and the liquefaction potential assessment based on Standard Penetration Tests for liquefied and non-liquefied sites were performed. Recorded ground motions from the event are presented and the local site effect on the occurrence of liquefaction is described briefly. Observed liquefaction case studies are presented. Ejected soils at liquefied sites were collected and the particle size distributions of ejected soils were analysed. SPT blow counts and the soil profiles at eight liquefied and non-liquefied sites were obtained. The factors of safety against liquefaction with depth and liquefaction potential index of the eight sites were estimated and compared with observed liquefaction areas during Gorkha earthquake. The liquefaction potential indices obtained from the analysis were found to be consistent with the field observation.