Use of Case Histories to Enhance Practical Geotechnical Engineering

A geotechnical case history is a complete cycle; spread over events such as, investigation, design, execution, completion, and monitoring, of understudy project. In case histories the events are continuously monitored, evaluated, modified (if required), executed and corresponding responses / effects are recorded. Case histories help us learn from the past without living in the past, their analysis envision us to enhance practical engineering in the present and future. A geotechnical case history may be performed in an organizational framework or initiated by an interested research engineer in an individual capacity. In all circumstances; a case history would aim at exploring questions concerning processes or techniques for a future project or testing of hypotheses based on the existing theoretical concepts. A case history therefore is an important research tool for educational evaluation and practical geotechnical engineering. Availability of up-to-date data sets of geotechnical case histories covering entire spectrum; from techniques / technologies to results / effects can help reduce both cost and time of future geotechnical projects. Knowledge gained from case histories can be used to develop geotechnical analytical models for optimization of designs. This paper is a case history of “Enhancement of Bearing Capacity by Dynamic Compaction” project carried out in alluvial deposits, in Pakistan. The authors intend analyzing the project with a view to contribute towards increased understanding of improvement of alluvial deposits by dynamic compaction technique

Enhancement of Bearing Capacity by Dynamic Compaction: A Case History

Deep Dynamic Compaction technique was used to improve soil bearing capacity in one of the project in Pakistan. It was first project in the country where Deep Dynamic Compaction technique was used for soil improvement. The soil at construction site composed of alluvial deposits. The sub-surface profile with in the depth of influence of proposed structure comprised of different layers of varying thickness within the construction site. The top 1-2 meter strata was an imported fill compacted in layers and composed of sandy silty clayey soil with percentage of fines as high as 75 percent The water table was located at 12 m depth. The construction alternatives included deep foundation and improvement of bearing capacity using dynamic compaction technique; the later was adopted in view of the economy of the project. The depth and degree of improvement was evaluated by comparing pre to post compaction Standard Penetration Tests (SPT) and measuring depth of the crater after each drop. The paper discusses briefly the compaction design, methodology for evaluation of effectiveness and resultant improvement in depth and lateral direction. The results of the compaction program of research project have also been compared with those of various case histories

From Case Histories to Conceptual Models

Geotechnical engineering deals with complicated and highly variable set of engineering principles. A typical geotechnical engineering project comprises site characterization, foundation / soil treatment design, execution, monitoring and quality control systems. Unlike some other civil engineering designs, highly variable soil conditions make a geotechnical designs an iterative and repetitive process which in-turn make these designs cost and time intensive. Economy and optimization of geotechnical designs are dependent on comprehensive site characterization and evaluation of multiple alternatives. Availability of up-to-date data sets of geotechnical case histories covering entire spectrum; from techniques / technologies to results can help reduce both cost and time of future geotechnical projects. Knowledge from case histories can be used to develop geotechnical constitutive and analytical models with the help of information technology; such models can lead us to many progressive and futuristic limits of geotechnical engineering. The authors of the paper intend to propose architectural development of “Geotechnical Information System (GTIS)”. The GTIS system covering fundamental geotechnical concepts, data of case histories such as; techniques, technologies employed, monitoring and quality control systems, results / effectiveness of techniques, will provide a framework for the following: • increased understanding of world-wide geotechnical issues by sharing lessons learnt which will help minimize barriers of uncertainty • enhancement of investigation and design procedures • development of economical and efficient technologies • identification of areas for collaborative research • development of “Geotechnical Artificial Intelligence Systems (GTAIS)

Landlessness and Rural Poverty in Pakistan

Although reducing rural poverty has been the key agenda of economic reforms in Pakistan, the rural poverty continued to rise during the 1990s. The causes of rural poverty are complex and multidimensional. The rural poor are quite diverse both in the problems they face, and the possible solutions to these problems are also different. The paper uses the most recent household data set available—PIHS 2001-02—to examine the causes of rural poverty, as to what accounts for its persistence and what policy measures should be taken to alleviate it. Poverty estimates using official poverty line suggest the high prevalence of rural poverty ranging from 39 percent to 48 percent in all provinces. Rural poverty is found to be strongly correlated with lack of asset in rural areas. The unequal land ownership in the country is found to be one of the major causes of rural poverty, as poverty level was the highest among the landless households followed by non-agriculture households. The incidence of landlessness is common in rural areas. About 67 percent households own no land in the country. Unusually, just 0.3 percent households own 55 and above acres of land across the country, suggesting a highly skewed landownership pattern. Gini Coefficient of landholding suggests that Punjab has the most unequal landownership pattern, followed by the NWFP, Sindh, and Balochistan. The highly unequal land distribution seems to have resulted in tenancy arrangements such as sharecropping, resulting in high prevalence of absolute poverty particularly in Sindh. A broad-based land reform programme, including land redistribution and fair and enforceable tenancy contracts together with rural public works programmes and access to credit, is critical to reducing rural poverty in Pakistan.Poverty, Pakistan

Performance evaluation of Cu-Ni 90/10 alloyed structures exposed to various seawater compositions and their remaining service life estimation

The Cu-Ni 90/10 alloy is extensively used in seawater applications mainly because of its excellent heat transferability, resistance toward corrosion and marine fouling. The corrosion resistance of Cu-Ni 90/10 has been found to be far superior in open natural seawater, however, several premature failures have often been reported during their exposure in the pollutant-rich seawater typically found near harbours, jetties and coastlines. This paper investigates the corrosion behaviour of Cu-Ni 90/10 alloyed coupons exposed to natural seawater, and pollutant-rich harbour seawater in a submerged position. Moreover, this research also investigates the corrosion mechanism on marine heat exchanger tubes of material that failed prematurely while operating in similar seawater compositions. The field experimental results for short-term corrosion results from coupons, and the long-term corrosion results from heat exchanger tubes have been evaluated, to formulate a relationship and corrosion modelling