Field Test Research on Embankment Supported by Plastic Tube Cast-in-place Concrete Piles   总被引：1，自引：1，他引：0  

Yonghui Chen  Changguang Qi  Hongyue Xu  Charles W. W. Ng 《Geotechnical and Geological Engineering》2013,31(4):1359-1368

The plastic tube cast-in-place concrete pile (TC pile) with a small diameter consists of pre-driven plastic tube filled with concrete. Based on the case of TC pile-reinforced embankment on soft ground, and according to the monitoring data of the TC pile-reinforced embankment system, the treatment effect and reinforcement characteristics for this system were analyzed. The field monitoring results indicates that the critical height of embankment is about 1.1 times the pile net spacing, and the small-spacing arranged TC piles can be applied to low embankment engineering; the load share rate can reflect the degree of soil arching more better and steadily and exceeds 70 % at the end of monitoring period; the settlements of pile cap and soil between piles mainly occurs in the embankment construction period; the different settlement between pile cap and soil approaches the maximum and then reduces gradually when the embankment height is about 2.2 times the pile net spacing. The variation of layered settlement and pore water pressure illustrates that the embankment settlement is mainly caused by the compression of soils within pile length, which is about 90 % of the total settlement; the influence depth of pore water pressure is about 1/3 pile length.  相似文献   

Dust-acoustic wave modulation in the presence of q-nonextensive electrons and/or ions in dusty plasma     

A. S. Bains  M. Tribeche  C. S. Ng 《Astrophysics and Space Science》2013,343(2):621-628

A study is presented of the nonlinear self-modulation of low-frequency electrostatic dust acoustic waves (DAWs) propagating in a dusty plasma, within the theoretical framework of the nonextensive statistics proposed by Tsallis. Using the reductive perturbation method (RPM), the nonlinear Schrödinger equation (NLSE) which governs the modulational instability (MI) of the DAWs is obtained. The presence of the nonextensive electron/ion distribution is shown to influence the MI of the waves. Furthermore it is observed that nonextensive distributed ions has more effect on the MI of the DAW than electrons.  相似文献   

地层学界近年来对新生代地层学名称使用的变化     

朱诚  黄铿 《地理学报》2009,64(9):1143-1147

随着国内外地层学界对新生代地层研究的不断深入,自1996年以来,国际地层学界对新生代地层学年代的划分不断更新。国际地层委员会2008年公布的方案中,新生代内第四纪的地位还未确定,它可能包括更新世,底界回溯到大约2.6 MaBP。随着中国第四纪研究在国际上的学术地位日益上升,在对新生代的划分上,表达中国学者建议的呼声将会越来越高。  相似文献   

Contact detection algorithms for three-dimensional ellipsoids in discrete element modelling     

Xiaoshan Lin  Tang-Tat Ng 《国际地质力学数值与分析法杂志》1995,19(9):653-659

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苏州1956年以来的降水变化及其空间差异研究   总被引：1，自引：0，他引：1  

陈德超  张晓波  陆建伟  黄铿 《水文》2008,28(6)

本文采用苏州大市自1956年以来的逐月降水观测数据,运用距平百分率(R)分析和GIS技术,时该地区近半个世纪来的降水变化特征及其空间分异规律进行研究.首先系统分析了1956～2006年苏州降水的年际、年内变化特征,并参照国际标准评价其降水正常概率;然后分别从苏州市域和城郊对比的角度,探讨了多年平均降水的区域差异及其与城市化的关系.  相似文献   

Tsunami threat to the Pacific coast of Canada due to local earthquakes     

Max Ng  Paul H. Le Blond  Tad S. Murty 《Natural Hazards》1992,5(2):205-210

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Gamma emitters in Hong Kong water     

Shun-Yin Lau  Chung-Keung Man  Wai-Kwok Ng  Shui-Chun Au 《Environmental Geology》1990,16(2):129-131

Water samples, representing seawater, river water, reservoir water, drinking water, and underground water were studied through gamma-ray spectral analysis. Only gamma emitters in the²³⁸U and²³²Th series and⁴⁰K were detected. No fission product was detected with specific activity above 0.1 Bq/kg. The present data could be the baseline for future monitoring of the radioactivity released from a nuclear plant being built at a 50-km distance from Hong Kong. The variation of detected specific activities may be due to geological differences and the effect of plants.  相似文献   

Centrifuge modelling of the effects of root geometry on transpiration-induced suction and stability of vegetated slopes   总被引：1，自引：0，他引：1  

C. W. W. Ng  V. Kamchoom  A. K. Leung 《Landslides》2016,13(5):925-938

Shallow landslides (i.e. 1–2-m depth) on both man-made and natural slopes are of major concern worldwide that has led to huge amount of socio-economical losses. The use of vegetation has been considered as an environmentally friendly means of stabilising slopes. Existing studies have focused on the use of plant roots with different geometries to mechanically stabilise soil slopes, but there are little data available on the contribution of transpiration-induced suction to slope stability. This study was designed to quantify both the hydrological and mechanical effects of root geometry on the stability of shallow slopes. Centrifuge tests were conducted to measure soil suction in slope models supported by newly developed artificial roots. These artificial roots exhibit three different representative geometries (i.e. tap, heart and plate) and could simulate the effects of transpiration. The measured suction was then back-analysed through a series of finite element seepage-stability analyses to determine the factor of safety (FOS). It is revealed that after a rainfall event with a return period of 1000 years, the slope supported by heart-shaped roots retained the highest suction within the root depth, and thus, this type of root provided the greatest stabilisation effects. The FOS of the slope supported by the heart-shaped roots, through both mechanical reinforcement and transpiration-induced suction, is 16 and 28 % higher than that supported by the tap- and plate-shaped roots, respectively.  相似文献   

Characterization of a hypoxia-responsive leptin receptor (omLepR(L)) cDNA from the marine medaka (Oryzias melastigma)     

Wong MM  Yu RM  Ng PK  Law SH  Tsang AK  Kong RY 《Marine pollution bulletin》2007,54(6):797-803

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Chemical Zone of Nephrite in Alamas,Xinjiang, China     

Yan Liu  Jun Deng  Guanghai Shi  Taijin Lu  Huaiyu He  Yi-Nok Ng  Chonghui Shen  Liqiang Yang  Qingfei Wang 《Resource Geology》2010,60(3):249-259

The Hetian deposit, located south of the Tarim Basin in Xinjiang, China, is one of the world's largest dolomite-related nephrite deposits. In the Alamas orebody of the deposit, nephrite occurs as veins or lenses along faults or fissures of the adjacent dolomitic marble. Chemical analyses using electronic microscope probe analysis and X-ray fluorescence spectroscope were carried out on nephrite and dolomitic marble samples collected from a cross section in Alamas to investigate zonal structure of the orebody. The nephrite in Alamas is predominately composed of tremolite with minor calcite, titanite and phlogopite, and that dolomitic marble is relatively pure with a FeO content less than 0.20 wt. %. Contents of color-inducing elements, such as Fe, Mn, and Cr, increase gradually as color changes from white through white-green and then to green, resulting in the formation of color-distinctive zones. Tremolite grain size increases as color changes from white through white-green to green. The trend may be consistent with temperature changes from dolomitic marble to granodiorite, which, in turn, suggests that both change in color from white to green and variations of grain size with increasing temperature resulting in formation of the nephrite zonal structure. Both nephrite zonal structure and minor minerals, such as calcite, titanite and phlogopite found in the contact, indicate that this dolomite-related nephrite orebody is of a metasomatic origin under assumed pressure of 100–200 MPa and temperature <550°C.  相似文献