ALBERT

Description: Standard Penetration Test (SPT) and cone penetration test (CPT) are the most widely used in situ tests to depict the soil stratigraphy and determine the geotechnical engineering of the subsurface soils. The CPT leaps out because of its capability to trace the resistance continuously and due to its accuracy, it is considered to be reliable than the SPT. The outcome of these tests is very important for the design procedures to be implemented for various geotechnical purposes. To effectively utilize all the available data, there is a need of updating the correlation between these two widely used in situ tests. This study implements the statistical linear regression model using a 107 SPT and 49 CPT measurements across the city of Lahore, Pakistan to develop correlations between the the uncorrected SPT blow counts (N) and cone resistance (qc) for various soils. The developed correlation is compared in terms of qc/N ratios with the previous published studies.

Description: Slope failures endanger the public safety and one of major hazard considered in mountainous terrain. In this paper, slope stability measures have been evaluated using the limit equilibrium method (LEM). A case study of slope failure from Birham land slide, Murree, Pakistan has been modelled using SLOPE/W program. In-situ boring tests are performed to collect laboratory test specimens. Geotechnical properties (i.e. shear strength and stiffness parameters) for the idealised slope sections are based onlaboratory tests performed on the collected in-situ specimens. Slope stability measures are evaluated in terms of factor of safety (FoS) for static and dynamic loading. Pseudo-static method is used for dynamic analysis, considering the Peak ground acceleration (PGA) from seismic hazard map of Pakistan. Results shows that static and dynamic FoS of original slope are inadequate therefore resistance to slip surface of original unstable slope is provided by slope geometry modification wit...

Description: Flood constitutes one of the world’s most serious environmental hazards. Flood bunds are the earthen hydraulic structures which are constructed along the River to control the Flood water to avoid damages to the infrastructures, crops, livestock and loss of human lives. Pakistan which lies in the Indus Basin has been facing severe threats and losses from the floods since histories. About 6807km length of flood embankment has been constructed to safeguard against the floods in the country. Punjab has been worst hit province by heavy floods and rains causing heavy loss. Geotechnical Evaluation is vital for proper functioning of such structures. In this study four flood bunds susceptible to potential embankment breaching during flood have been selected along river Chenab in district Muzaffar Garh Irrigation zone. Suite of analysis using GeoStudio software (SLOPE/W and SEEP/W for stability and seepage analysis respectively) has been performed by considering four different critical sc...

Description: The degree of mechanical reinforcement provided by plants depends upon its roots distribution in the soil and mechanical properties of the roots. The mechanical properties and distribution of root traits (root diameter and number) in the soil of the standing forest depends on the tree stem diameter. This variation of root traits with tree stem diameter is rarely investigated. Therefore, this research presents the effect of tree stem diameter on the distribution of roots within the standing forest of Cunninghamia in the Longchi forest area, Sichuan province, China. In this area, shallow landslides take place frequently. We investigated the root traits distribution for trees with different stem diameters, i.e., 220 mm, 320 mm, 450 mm, and 468 mm, to show the variation of roots distribution in the soil with stem diameter. The root architecture of the selected trees was studied by step excavation method of the root zone accompanied by measurement of roots physical parameters (roots number and roots diameter) and indices (roots area ratio (RAR), roots biomass (RB), and roots distribution (RD)). We measured the root’s maximum tensile strength by performing root tensile tests in the laboratory. The field and laboratory-measured data were used to estimate the root cohesion by both the commonly used model Wu and Waldron Model (WWM) and Fiber Bundle Model (FBM). The results indicate that the tree stem diameter correlates with both the root distribution and the tensile strength. The roots indices and root cohesion increase with an increase in the diameter of the tree. Further, RAR decreases with depth and lateral distance from the tree stem, while the maximum values were observed in 10 cm depth. The relationship between roots diameter and roots tensile strength is established through power function. The average root cohesion estimated for a tree with stem diameter 220 mm is 23 kPa, 29 kPa for 320 mm, 54 kPa for 450 mm, and 63 kPa for 460 mm. This effect of stem diameter on the increase of soil shear resistance should be considered while evaluating the stability of slopes in standing forests. The comparison between WWM and FBM for investigated species suggests that WWM estimates the cohesion values greater than FBM by 65%.