William Checkley,professor of medicine and a pulmonary and critical care specialist at Johns Hopkins University(Baltimore,MD,USA)has seen kitchens with stalactites.But not the kind found in caves.“You walk in,and the...William Checkley,professor of medicine and a pulmonary and critical care specialist at Johns Hopkins University(Baltimore,MD,USA)has seen kitchens with stalactites.But not the kind found in caves.“You walk in,and the smoke is everywhere,”said Checkley.“It is difficult to breathe—you cough,your eyes burn.”Layers of soot from cookfires cover the walls and,in some extreme cases,form stalactites that hang from the ceiling.展开更多
Geotechnical properties of sedimentary rocks exposed along upper Egypt-Red Sea road were investigated to evaluate their geotechnical behavior. One of the most important aims of this work was to determine the engineeri...Geotechnical properties of sedimentary rocks exposed along upper Egypt-Red Sea road were investigated to evaluate their geotechnical behavior. One of the most important aims of this work was to determine the engineering problems affected on the road due to the geotechnical behavior of the studied sedimentary rocks and to suggest the suitable solution. Specific weight, unconfined compressive strength, slaking durability and free swelling were measured. The results showed that the studied crystalline limestone, marly limestone and Issawia limestone had higher unconfined compressive strength values ranging from 34,184.00 kN/m2 to 42,602.00 kN/m2 and the studied shale, siltstone and coral reef had lower values ranging from 3,689.00 kN/m2 to 6,933.00 kN/m2. The results showed also that the studied shale, siltstone and mudstone had fast to very fast slaking rate and their slaking amount described as low to medium after Gamble＇s slake durability classification. Replacement and/or chemical stabilization （using lime and/or cement kiln dust） of the expansive sedimentary rocks （shale and mudstone） were recommended to reduce the swelling. Geophysical investigations including shallow seismic, microgravity and GPR （ground penetrating radar） were recommended to scan the sub-grade of the road at El Maaza plateau to determine possible other caves and large voids under the road to avoid its collapse.展开更多
THE Yellow River, with its huge amount of silt charge from the Loess Plateau, is the secondlargest river in China. Its lower reach has become a famous hanging river because of serioussilting up, and the magnitude of d...THE Yellow River, with its huge amount of silt charge from the Loess Plateau, is the secondlargest river in China. Its lower reach has become a famous hanging river because of serioussilting up, and the magnitude of discharge changes much from season to season. As a result ofsilting, migration of the stream channel happens frequently. Lateral erosion of channel or pointbars, and scarp slopes forming during the erosion may be often observed. The silt stalactite,hitherto not reported, usually forms on surfaces of the slope. As a newly found kind of sedirnen-tary structure, the silt stalactite may have some significance to the study of sedimentary envi-ronments and paleoclimate.展开更多
文摘William Checkley,professor of medicine and a pulmonary and critical care specialist at Johns Hopkins University(Baltimore,MD,USA)has seen kitchens with stalactites.But not the kind found in caves.“You walk in,and the smoke is everywhere,”said Checkley.“It is difficult to breathe—you cough,your eyes burn.”Layers of soot from cookfires cover the walls and,in some extreme cases,form stalactites that hang from the ceiling.
文摘Geotechnical properties of sedimentary rocks exposed along upper Egypt-Red Sea road were investigated to evaluate their geotechnical behavior. One of the most important aims of this work was to determine the engineering problems affected on the road due to the geotechnical behavior of the studied sedimentary rocks and to suggest the suitable solution. Specific weight, unconfined compressive strength, slaking durability and free swelling were measured. The results showed that the studied crystalline limestone, marly limestone and Issawia limestone had higher unconfined compressive strength values ranging from 34,184.00 kN/m2 to 42,602.00 kN/m2 and the studied shale, siltstone and coral reef had lower values ranging from 3,689.00 kN/m2 to 6,933.00 kN/m2. The results showed also that the studied shale, siltstone and mudstone had fast to very fast slaking rate and their slaking amount described as low to medium after Gamble＇s slake durability classification. Replacement and/or chemical stabilization （using lime and/or cement kiln dust） of the expansive sedimentary rocks （shale and mudstone） were recommended to reduce the swelling. Geophysical investigations including shallow seismic, microgravity and GPR （ground penetrating radar） were recommended to scan the sub-grade of the road at El Maaza plateau to determine possible other caves and large voids under the road to avoid its collapse.
文摘THE Yellow River, with its huge amount of silt charge from the Loess Plateau, is the secondlargest river in China. Its lower reach has become a famous hanging river because of serioussilting up, and the magnitude of discharge changes much from season to season. As a result ofsilting, migration of the stream channel happens frequently. Lateral erosion of channel or pointbars, and scarp slopes forming during the erosion may be often observed. The silt stalactite,hitherto not reported, usually forms on surfaces of the slope. As a newly found kind of sedirnen-tary structure, the silt stalactite may have some significance to the study of sedimentary envi-ronments and paleoclimate.
