IMPORTANCE OF GEOTECHNICS IN TODAY\u27S AND FUTURE CIVIL ENGINEERING - Public image, risks and responsibilities and future aspects of civil/geotechnical engineering

This contribution is dedicated to the public image of the civil engineer and geotechnical engineer, respectively, seen from an ethical and philosophical point of view. Discrepancies between professional opinions, the gap between theory and practice, pros and cons of codes or regulations, and the lifelong learning society are discussed on the basis of the author\u27s nearly fifty years of comprehensive professional experience. Furthermore, the environmental challenge to civil/geotechnical engineering due to climate change and global increase in population is emphasized. Finally, the younger engineering generation\u27s prospects in the future are addressed and recommendations are given

Geophysical investigation into the integrity of a reclaimed open dumpsite for civil engineering purpose

Structural failure is one of the concerns of earth scientists in the in the recent time. Most of the building engineers neglect investigation into the subsurface structure prior to construction without taking into cognizance the soil type and its variation which is one of the contributing factors to frequent building collapse in this era. Integrated geophysical methods involving ground magnetic, Very Low Frequency-Electromagnetic (VLF-EM) and Vertical Electrical Sounding (VES) were adopted with a view to investigating into the integrity of a reclaimed open dumpsite in Oyo for civil engineering worthiness. Three (3) traverses were occupied for ground magnetic and VLF-EM survey. A total length of 100 m was occupied in each traverse along E-W orientation with inter-station spacing of 10 m. Six (6) VES stations were occupied along two geoelectric profiles in the study area. The ground magnetic study showed magnetic highs and lows both on the profiles and the generated 2-D map. The magnetic highs are competent zones for civil engineering construction while magnetic lows are incompetent zones. The VLF result revealed conductive and non-conductive zones. More than half of the area of study is characterized with conductive signatures. Conductive zones are regarded as the incompetent zones while the non-conductive zones are regarded as competent zones. The VES result showed that the five out of six VES points occupied are underlain with fractured bedrock while only VES 3 showed fresh bedrock. It is concluded that the study area unsuitable for the construction of giant structure

Instrumented Load Test on a Bent Pile

The load carrying capacity of a bent shell pile in soft silts and clays was determined from an instrumented test. Lateral pile displacements along the pile were measured during loading and unloading using an inclinometer traveling in a plastic casing. Pile capacity was estimated by Johnson\u27s (1962) method prior to the load test and by the STRUDL structural engineering program after performing the load test. Both methods adequately predicted the pile performance. STRUDL, however, accommodated more realistic soil parameter variation and boundary conditions necessary for an integral soil-pile-structure interaction analysis

Geomechanics Challenges and its Future Direction – Food for Thought

Geomechanics has proven to be the backbone of safe and cost effective mining practice. However, experience shows it still does not have the appreciation of most mine managements until there is a fatality or costly ore sterilization. The problem can be traced back to the training of mining engineers. The subject is also picked up later in life by other professionals with limited background in geology. The consequences of these limitations are lack of fundamental knowledge in the subject by some who practice it. This lack of understanding has affected the growth and maturity of the subject of rock mechanics, a key component of geomechanics. Today, we are beginning to understand that failure criteria that were inherited from soil mechanics for appli-cation to rock are wrong and misleading. Despite these problems, some major achievements have been made towards a better understanding of rock behavior under load. Many more challenges still lie ahead. This paper takes a look at the history of rock mechanics, and therefore geomechanics, its development, required training, present status and what lies ahead in the future. The goal is to provide educators, industry and practicing engineers what it takes to be a good rock engineer and the real benefits of the subject for the good of society

Emerging Innovative Solutions Enhancing Practical Geotechnical Engineering

This paper presents two case histories, wherein double twisted hexagonal wire mesh crates and netting were used as a solution for geotechnical problems that aroused while execution. One of which is worldwide known and one of the most prestigious projects of India - Konkan Railway, and second is internationally noted tourist spot- Amby Valley Sahara lake city. In Konkan Railway project, double twisted wire mesh was used as a basic material for variety of problems like rock fall prevention, Gravity walls at the base of rock slopes, Baby Gabions as ballast retention for railway tracks, Platform Gabions etc. Adoption of Gabions and rock fall netting was one of its types of innovative solutions for this project. For Amby Valley Sahara lake city project, global instability of high cuttings in soil and heavy landslides were the major geotechnical problems. Many traditional solutions have failed at the site. Gabion retaining walls were adopted of heights ranging from 2 m to 13 m. Though there were initial failures mainly due to faulty construction, the same system of Gabion walls was continuously adopted due to its flexible, permeable and environment friendly nature

Experimental study on dynamic properties of sand-rubber mixtures in a small range of shearing strain amplitudes

Sand-rubber mixtures has characteristics of light weight, cheap and environmental-friendly, thereby it has a great potential to be used in geotechnical engineering for sustainable development. Dynamic properties (i.e. shear modulus and damping ratio) of sand-rubber mixtures in a small range of shearing strain amplitudes (i.e. 10-6-10-4) were investigated in this study through a series of resonant column tests. The effects of shearing strain amplitude, confining pressure and rubber content on dynamic shear modulus (G), maximum dynamic shear modulus (Gmax), damping ratio (D) and dynamic shear modulus ratio G/Gmax of the mixtures were also discussed. Based on the analyses of the relationship among confining pressure, rubber content and Gmax, an empirical formula for predicting Gmax considering the effects of confining pressure and rubber content was also proposed. The model prediction agreed with the experimental results very well

Impact assessment of wastewater discharge from a textile industry in Lagos, Nigeria

The quality of effluent from a wool and synthetic textile manufacturing company in Nigeria was examined by obtaining triplicate samples per week over a 6-week period. This was done to measure the waste-load and volume from the textile industry. Obtained samples were analyzed for 18 physicochemical parameters such as pH, color, turbidity, total suspended solids, total dissolved solids (TSS), conductivity, dissolved oxygen, biochemical oxygen demand (BOD), chemical oxygen demand (COD), chloride, nitrates, phosphates, some heavy metals and odor. Heavy metals, phosphate, and color were analyzed using spectrophotometer while dissolved oxygen and BOD were analyzed using azide modification method. The effluents were found to pass the national standard for the effluent limit for 13 parameters but exceeded specified limits for pH in one sample and, COD, TSS, color, turbidity and odor in all samples. Turbidity was found to exceed national limits by 100 to 300%; COD exceeded limits by 20% to 500%; TSS exceeded limits by 10% to 110% in 5 out of 6 samples analyzed. All obtained samples were dark colored and exceeded prescribed limits by 2,000 to 3,000% in all samples. Likewise, all six samples had an offensive odor. It was recommended that strict compliance with stipulated standards was necessary for the protection of public health and the environmen

Soil-Bentonite Slurry Trench Cutoff Wall Proposal

This is the proposal to the National Science Foundation for a soil-bentonite slurry trench cutoff wall. The proposal includes a project summary, description of the project, and the resources implemented on the project