Unloading induces negative excess porewater pressure in soil mass around a foundation pit during excavation. In this work, the dissipation rule of negative excess porewater pressure after excavation was studied. Analy...Unloading induces negative excess porewater pressure in soil mass around a foundation pit during excavation. In this work, the dissipation rule of negative excess porewater pressure after excavation was studied. Analytical formulas for calculating the negative excess porewater pressures and the effective stresses were derived based on one-dimensional consolidation theory and Terzaghi’s effective stress principle. The influence of the dissipation of negative excess porewater pressure on earth pressure inside and outside a foundation pit and the stability of the retaining structure were analyzed through a numerical example. It was indicated that the dissipation of negative excess porewater pressure is harmful to the stability of the retaining structure and that rapid construction can make full use of the negative porewater pressure.展开更多
Based on the studies of earthquake activity, tectonic movement, crustal shortening rate, fault activity, local stress field and historical characteristics of strong earthquake activities in Xinjiang, we divide the sou...Based on the studies of earthquake activity, tectonic movement, crustal shortening rate, fault activity, local stress field and historical characteristics of strong earthquake activities in Xinjiang, we divide the south part of Xinjiang into 4 seismotectonic zones, namely, the eastern segment of south Tianshan seismic belt, the Kalpin block, the Kashi-Wuqia junction zone, and the west Kunlun Mountains seismic belt. Using earthquake catalogues from Xinjiang since 1900, and on the basis of integrity analysis of earthquake records in different magnitude ranges, the seismicity state of different seismotectonic zones is analyzed quantificationaUy by calculating the mean value of annual strain energy release, annual rate of earthquakes with different lower limits of magnitude, b-value, and the parameter m of accelerating strain release model. The characteristic indexes of seismicity state for each of the seismic tectonic zones are then determined, which provide a quantitative basis for earthquake tendency analysis and judgment.展开更多
基金Project (No. 20030335027) supported by the National ResearchFoundation for the Doctoral Program of Higher Education of China
文摘Unloading induces negative excess porewater pressure in soil mass around a foundation pit during excavation. In this work, the dissipation rule of negative excess porewater pressure after excavation was studied. Analytical formulas for calculating the negative excess porewater pressures and the effective stresses were derived based on one-dimensional consolidation theory and Terzaghi’s effective stress principle. The influence of the dissipation of negative excess porewater pressure on earth pressure inside and outside a foundation pit and the stability of the retaining structure were analyzed through a numerical example. It was indicated that the dissipation of negative excess porewater pressure is harmful to the stability of the retaining structure and that rapid construction can make full use of the negative porewater pressure.
基金supported by the Special Scientific Research Funds for Earthquake Studies, entitled "Development of Dynamic Evaluation System of Seismicity State in the Chinese Continent (Grant No. 200708020)"
文摘Based on the studies of earthquake activity, tectonic movement, crustal shortening rate, fault activity, local stress field and historical characteristics of strong earthquake activities in Xinjiang, we divide the south part of Xinjiang into 4 seismotectonic zones, namely, the eastern segment of south Tianshan seismic belt, the Kalpin block, the Kashi-Wuqia junction zone, and the west Kunlun Mountains seismic belt. Using earthquake catalogues from Xinjiang since 1900, and on the basis of integrity analysis of earthquake records in different magnitude ranges, the seismicity state of different seismotectonic zones is analyzed quantificationaUy by calculating the mean value of annual strain energy release, annual rate of earthquakes with different lower limits of magnitude, b-value, and the parameter m of accelerating strain release model. The characteristic indexes of seismicity state for each of the seismic tectonic zones are then determined, which provide a quantitative basis for earthquake tendency analysis and judgment.
