Lately the subject of sinkholes has appeared on press due to a fatal incident in Florida USA and several incidents in Samara Russia. In the first case a man sleeping in his bedroom in Tampa Florida, disappeared when a 5 – 10m diameter sinkhole opened suddenly under his house. The estimated depth of the sinkhole … Continue reading Sinkholes: Is it a natural or man induced hazard?
Coming back to the issue of stiff fissured clay slopes, one very important question is the standup time of a slope excavated or formed (natural erosion etc) with higher inclination than the one that would be the outcome using fully softened shear strength. Skempton (1970) in his paper “First time slides in over consolidated clays”, … Continue reading How long can stiff fissured clay slopes stand?
IAEG (International Association for Engineering Geology) organizes the XII Congress that will be held in Torino (Italy) from 15 to 19 September, 2014. The topic of the IAEG XII Congress is: “Engineering Geology for Society and Territory” and aims to explore and analyze the role of Engineering Geology. There are four main themes offered … Continue reading IAEG XII Congress: Engineering Geology
A very difficult issue is the design of slopes or cuts in stiff fissured clays (pic 1). The difficulty lies in the evaluation of shear strength for stability calculations. Much work has been done on this issue especially by Skempton (1964) with his excellent Forth Ranking Lecture titled: “Long-term stability of clay slopes” and many … Continue reading Slope design in stiff fissured clays
The situation is like this: A major problem occurs in a bridge abutment and significant differential settlement between abutment and road is observed. The Owner decides to investigate the situation and assigns the job to a joint collaboration between a University and a Geotechnical Consultancy Firm. The collaboration requests the execution of three boreholes to … Continue reading Proper amount of geotechnical investigation
Reading on the news about the dramatic landslide-mudflows (picture) that occurred (again) in Petropolis near Rio de Janeiro, with significant fatalities, one thinks could this have been predicted and more so avert it? Even in an area prone to superficial mudflows and thin landslides, it is very difficult to accurately predict the occurrence of such a … Continue reading How difficult is to evaluate superficial landslides – mudflows?
Today I came across a very interesting paper regarding site investigation with SPT and CPT. In this paper written by J. D. Rogers, the historical development of SPT from its creation from Charles R. Gow, to its modification and standardization by K. Terzaghi and A. Casagrande and its standardized use today are presented. The road … Continue reading SPT field testing
On February 2011 an earthquake of M=6.3 magnitude struck Christchurch in New Zealand causing the death of 185 people. This earthquake has particular significance for geotechnical engineers, since a number of geotechnical phenomena were manifested during and after the event. Liquefaction in a wide area and landslides (rockfalls), caused widespread damage across Christchurch especially in … Continue reading Engineering Geology – Christchurch Earthquake Presentation
Geotechnical Engineers, Engineering Geologists and Geoprofessionals in general are involved in evaluating and quantifying earth processes, earth materials, and human intervention on or in the earth in a way that can be used to manage geological risk and to produce safe and economical structures such as tunnels, dams, cuts etc. In order to produce such … Continue reading Visual observations and field experience versus mathematical formulations and office work
RQD was introduced by D. U. Deere in 1964 for a quantitative description of rock mass. The RQD is defined as the percent ratio of the sum of core pieces with higher than 10cm length to the total drill run. Based on the percent or RQD from 0-100% the rock mass quality can be assessed. … Continue reading How easy RQD estimations are?
