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薄层沥青路面试验研究
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作者 丁洪民 吕国林 《东北公路》 北大核心 1994年第4期20-25,共6页
本文主要论述在白城地区的具体自然气候条件及中等交通量的情况下修建薄层路面的可能性。论文中介绍了薄层路面的设计、结构组合及试验路的测试结果。修筑薄层路面要求有足够强度的基层结构,要求有足够稳定的土基。论文的最后部分对薄... 本文主要论述在白城地区的具体自然气候条件及中等交通量的情况下修建薄层路面的可能性。论文中介绍了薄层路面的设计、结构组合及试验路的测试结果。修筑薄层路面要求有足够强度的基层结构,要求有足够稳定的土基。论文的最后部分对薄层路面的经济效益进行了分析。 展开更多
关键词 强基 稳土基 薄层路面 沥青路面
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Stress and Displacement Distribution of Soft Clay Slope with 2D and 3D Elastoplastic Finite Element Method
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作者 严祖文 阎澍旺 李飒 《Transactions of Tianjin University》 EI CAS 2006年第4期308-312,共5页
Based on elastoplastic model, 2D and 3D finite element method (FEM) are used to calculate the stress and displacement distribution in the soft clay slope under gravity and uniform load at the slope top. Stability an... Based on elastoplastic model, 2D and 3D finite element method (FEM) are used to calculate the stress and displacement distribution in the soft clay slope under gravity and uniform load at the slope top. Stability analyses indicate that 3D boundary effect varies with the stress level of the slope. When the slope is stable, end effect of 3D space is not remarkable. When the stability decreases, end effect occurs; when the slope is at limit state, end effect reaches maximum. The energy causing slope failure spreads preferentially along y-z section, and when the failure resistance capability reaches the limit state, the energy can extend along x-axis direction. The 3D effect of the slope under uniform load on the top is related to the ratio of load influence width to slope height, and the effect is remarkable with the decrease of the ratio. 展开更多
关键词 slope stability soft clay soil elastoplasticity finite element method end effect stress analysis
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Design of micropiles to increase earth slopes stability 被引量:4
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作者 孙书伟 王家臣 卞晓琳 《Journal of Central South University》 SCIE EI CAS 2013年第5期1361-1367,共7页
A methodology was proposed for the design of micropiles to increase earth slopes stability. An analytic model based on bearn-colurnn equation and an existing P-y curve method was set up and used to find the shear capa... A methodology was proposed for the design of micropiles to increase earth slopes stability. An analytic model based on bearn-colurnn equation and an existing P-y curve method was set up and used to find the shear capacity of the micropile. Then, a step-by-step design procedure for stabilization of earth slope with rnicropiles was introduced, involving six main steps: 1) Choosing a location for the rnicropiles within the existing slope; 2) Selecting micropile cross section; 3) Estimating length of rnicropile; 4) Evaluating shear capacity of mieropiles; 5) Calculating spacing required to provide force to stabilize the slope; 6) Designing the concrete cap beam. The application of the method to an embankment landslide in Qinghai Province was described in detail. In the final design, three rows of rnicropiles were adopted as a group and a total of 126 rnicropiles with 0.23 m in diameter were used. The micropile length ranged between 15 and 18 m, with the spacing 1.5 m at in-row direction. The monitoring data indicate that slope movement has been effectively controlled as a result of the slope stabilization measure, which verifies the reasonability of the design method. 展开更多
关键词 micropiles earth slope stabilization lateral response analysis design method P-y curve
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Natural Nitrogen-15 Abundance of Ammonium Nitrogen and Fixed Ammonium in Soils
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作者 SHISHU-LIAN XINGGUANG-XI 《Pedosphere》 SCIE CAS CSCD 1992年第3期265-272,共8页
The present article deals with the natural nitrogen-15 abundance of ammonium nitrogen and fixed ammonium in different soils. Variations in the natural 15N abundance of ammonium nitrogen mineralized in soils under anae... The present article deals with the natural nitrogen-15 abundance of ammonium nitrogen and fixed ammonium in different soils. Variations in the natural 15N abundance of ammonium nitrogen mineralized in soils under anaerobic incubation condition were related to soil pH. The δ 15N of mineralizable N in acid soils was lower but that in neutral and calcareous soils was higher compared with the δ 15N of total N in the soils. A variation tendency was also found in the δ 15N of amino-acid N in the hydrolysates of soils. The natural 15N abundance of fixed ammonium was higher than that of total N in most surface soils and other soil horizons, indicating that the increase of δ 15N in the soil horizons beneath subsurface horizon of some forest soils and acid paddy soils was related to the higher δ 15N value of fixed ammonium in the soil. 展开更多
关键词 amino-acid N ammonium nitrogen fixed ammonium natural 15N abundance
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Base stability analysis of braced deep excavation in undrained anisotropic clay with upper bound theory 被引量:8
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作者 WANG LiZhong LONG Fan 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第9期1865-1876,共12页
It is imperative to evaluate factor of safety against basal heave failure in the design of braced deep excavation in soft clay.Based on previously published field monitoring data and finite element analyses of ground ... It is imperative to evaluate factor of safety against basal heave failure in the design of braced deep excavation in soft clay.Based on previously published field monitoring data and finite element analyses of ground settlements of deep excavation in soft clay,an assumed plastic deformation mechanism proposed here gives upper bound solutions for base stability of braced deep excavations.The proposed kinematic mechanism is optimized by the mobile depth(profile wavelength).The method takes into account the influence of strength anisotropy under plane strain conditions,the embedment of the retaining wall,and the locations of the struts.The current method is validated by comparison with published numerical study of braced excavations in Boston blue clay and two other cases of excavation failure in Taipei.The results show that the upper bound solutions obtained from this presented method is more accurate as compared with the conventional methods for basal heave failure analyses. 展开更多
关键词 braced deep excavation base stability upper bound theory soil anisotropy
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On the instability of offshore foundations: theory and mechanism 被引量:4
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作者 GAO FuPing LI JinHui +1 位作者 QI WenGang HU Cun 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2015年第12期125-141,共17页
As the offshore engineering moving from shallow to deep waters, the foundation types for fixed and floating platforms have been gradually evolving to minimize engineering costs and structural risks in the harsh offsho... As the offshore engineering moving from shallow to deep waters, the foundation types for fixed and floating platforms have been gradually evolving to minimize engineering costs and structural risks in the harsh offshore environments. Particular focus of this paper is on the foundation instability and its failure mechanisms as well as the relevant theory advances for the prevailing foundation types in both shallow and deep water depths. Piles, spudcans, gravity bases, suction caissons, and plate anchors are detailed in this paper. The failure phenomena and mechanisms for each type of foundations are identified and summarized, respectively. The theoretical approaches along with sophisticated empirical solutions for the bearing capacity problems are then presented. The major challenges are from flow-structure-soil coupling processes, rigorous constitutive modeling of cyclic behaviors of marine sediments, and the spatial variability of soil properties for large-spreading structures. Further researches are suggested to reveal the instability mechanisms for underpinning the evolution of offshore foundations. 展开更多
关键词 failure mechanism bearing capacity fluid-structure interaction offshore foundation soil dynamics
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