Developments in Geotechnical Engineering 

About: Developments in Geotechnical Engineering is an academic journal. The journal publishes majorly in the area(s): Finite element method & Liquefaction. It has an ISSN identifier of 0165-1250. Over the lifetime, 374 publications have been published receiving 3700 citations.

Rock fracture mechanics : principles, design, and applications

Abstract: Preface. Contents. List of Notations. 1. Introduction. 2. Some Fundamental Aspects of Mechanics. 3. The Griffith Theory and the Evolution of Modern Fracture Mechanics. 4. Linear Elastic Fracture Mechanics and Fracture Initiation Theories. 5. Determination of Stress Intensity Factors. 6. Aspects of Non-linear Elastic Fracture Mechanics. 7. Some Aspects of Statistical Fracture Mechanics. 8. Mode I Fracture Toughness Testing. 9. Mode II and Mixed Mode I-II Fracture Toughness Testing. 10. Interrelationships Between Fracture Toughness, Hardness Index and Physico-Mechanical Properties of Rocks. 11. Fracture Mechanics Applied to Hydraulic Fracture Propagation and In Situ Stress Determinations. 12. Fracture Mechanics Applied to Rock Fragmentation by Cutting Action. 13. Fracture Mechanics Applied to Rock Fragmentation due to Blasting. 14. Fracture Mechanics Applied to Analysis of Rockbursts. 15. Fracture Mechanics Applied to Design and Stability of Rock Slopes Engineering Problems. Appendix: A Compilation of Mode I Fracture Toughness Values of Rocks. References. Supplementary List of Recommended References. Index.

Gravitational Creep of Rock Masses on Slopes

Abstract: Large-scale gravitational creep of rock masses on slopes is a type of slow landsliding, in which zones of creep can extend a hundred metres or so below the surface. It excludes movement of surficial materials, such as solifluction and debris flows. As used in this report, creep is the very slow downward and outward movement of a mass of earth material adjoining a slope, generally without the formation of a continuous rupture surface. Measured rates of large-scale rock creep range from about 2 cm per year to 20 cm per day. Large-scale rock creep on slopes has been observed, measured, and described in various parts of the world, including Europe, New Zealand, Iran, South America, and the United States. Numerous examples from these places show that creep proceeds in several different ways in different geologic settings: (1) by valley ward squeezing out of weak ductile rocks overlain by or interbedded with more rigid rocks, causing tensional fracturing and outward movement of the more rigid rocks as well, sometimes with upward bulging in the centers of valleys; (2) by distortion and buckling of dipping interbedded strong and weak rocks or by creeping of rigid over soft rocks without buckling; (3) by movement distributed over a thick zone in relatively uniform material; (4) by incremental movement along a dipping rough-surfaced plane; (5) by deep-seated bending, folding, and plastic flow of rocks on slopes; and (6) by bulging, spreading, and fracturing of steep-sided ridges in mountainous areas. There may be still other types of creep that have not yet been recognized. In some places creep of rock masses proceeds continuously, under normal gravitational stresses; in other places it occurs in increments and may or may not require a trigger, such as an earthquake. Creep is known to precede sudden, catastrophic sliding (creep rupture), as at the Vaiont Reservoir in Italy, but it also may continue for years with no sign of sudden or accelerated movement. The mechanism that produces “spreading” of mountain ridges with uphill-facing scarps and trenches on hillsides is still not completely understood. Earthquake shaking, tectonic uplift, rapid stream erosion, and steepening of valley sides with removal of lateral support by glaciers now melted, could all have acted, separately or in combination, to cause this type of movement. Gravitational forces acting on steep-sided ridges probably cause tensional spreading of the ridge, which causes the sides of the ridge to fracture. Movement along these fractures or along pre-existing discontinuities forms trenches and uphill-facing scarps as the sides of the ridge bulge outward and the top subsides. Recognition and understanding of large-scale gravitational creep is vital in site selection and design of major engineering structures, particularly in high mountains. Gravitational creep may change to sudden catastrophic slide movement, as well illustrated by the slide at Vaiont. In places where valley sides are moving horizontally or bulging outward, engineering structures in the valley bottom will be subjected to both upward and lateral pressure, owing to bowing up of the valley bottom or closing in of the sides.

Nevados Huascarán Avalanches, Peru

Abstract: Two catastrophic avalanches in 1970 and 1962, and one even larger pre-Columbian avalanche, originated from Nevados Huascaran, the highest peak in the Peruvian Andes. The most recent avalanche, which was earthquake-triggered, had a volume on the order of 50–100 × 106 m3 and caused an estimated 18,000 casualties, mainly in the city of Yungay. The 1962 avalanche, with an approximate volume of 13 × 106 m3 killed about 4000 people, mostly in the city of Ranrahirca. Prior to 1962, there were no major avalanches from Nevados Huascaran since the arrival of the Spaniards in the early 16th century, but there is clear geologic evidence that the historic avalanches occurred within an area covered by debris from an enormous pre-Columbian avalanche. Fissuring of the ice cap on Nevados Huascaran above the avalanche source area suggests that the peak remains unstable despite two recent avalanches and that a significant avalanche hazard remains with respect to communities in the valley below. The avalanches originated from between 5400 and 6500 m elevation on the west face of the north peak of Nevados Huascaran and traveled 16 km to the Rio Santa (altitude about 2400 m) at velocities that averaged about 280 km/ hr in 1970, 170 km/hr in 1962, and possibly 315–355 km/hr for the pre-Columbian event. At their lower ends the two historic avalanches graded into debris flows that continued down the Rio Santa at decreased velocity where they caused extensive additional destruction. The large horizontal runout of the debris and the associated extreme velocities of the three avalanches appear to be related primarily to their fluidity and extreme height of fall. The fluidity results from entrainment in the debris of large volumes of snow and meltwater derived from Glacier 511 immediately below the source area. During the 1970 event, some of the debris was accelerated to velocities on the order of 1000 km/hr, velocities that are in excess of what would be expected for a purely gravitational fall. Such abnormally high velocities are suggested by the combination of excessive distances to which boulders weighing several tons were hurled through the air (up to 4 km), the relationship between missile mass and impact crater size, and spattering of mud far beyond the limits of the avalanche on trajectories that appear to be inclined downward at low angles to the horizontal.