摘要：
Nanotechnology is an extension of sciences and technologies that deal with particles less than 100 nm. This paper reviews previous studies on how nanomaterials work and what their advantages are in subgrade and pavement engineering. In subgrade engineering, the nanomaterials particles can not only improve the physicochemical and mechanical properties of subgrade soils by filling the voids between soil particles but also promote hydration reaction between cement and ion exchange between soil particles. In pavement engineering, the water stability, rutting resistance, fatigue resistance and optical properties of flexible pavements are enhanced by adding nanomaterials into the asphalt mixture. Nanosilica enhances the interface between cement pastes and aggregates and promotes the pozzolanic reaction of concrete, thus, mechanical properties of concrete pavements are improved. Compared with traditional materials, nanomaterials play a promising role in subgrade and pavement engineering, benefitting from their environmental friendliness, lower environmental disturbance, better price/performance ratio and higher durability.
摘要：
To investigate the influence of confining pressures and temperatures on the seepage characteristics of fractured rocks, seepage tests were conducted on a fractured silty mudstone using a self-developed experimental system, and the effects of different factors on coefficient of permeability were discussed. The results showed that the increasing confining pressure will gradually decrease the coefficient of permeability, and this process is divided into two stages: 1) the fast decrease stage, which corresponds to a confining pressure less than 30 kPa, and 2) the slow decrease stage, which corresponds to a confining pressure larger than 30 kPa. Unlike confining pressure, an increase in temperature will increase the coefficient of permeability. It is noted that fracture surface roughness will also affect the variation of coefficient of permeability to a certain extent. Among the three examined factors, the effect of confining pressure increases is dominant on fracture permeability coefficient. The relationship between the confining pressure and coefficient of permeability can be quantified by an exponential function.
关键词：
Nanotalc;Disintegrated Carbonaceous Mudstone;Shear Strength;Cohesion;Angle of Internal Friction
摘要：
This work was aimed to improve the shear strength of disintegrated carbonaceous mudstone (DCM) with nanotalc (NT). A series of direct shear tests were carried out on the NT-modified DCM specimens to determine their shear strengths at various NT concentrations. Subsequently, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed to reveal the underlying mechanism which the results showed that shear strength was first increased and then decreased with increasing certain NT concentration. Moreover, the increase in NT concentration also resulted in rise in cohesion and reduction in angle of internal friction. The optimum NT concentration for shear strength improvement of DCM is 4%. This improvement of shear strength is achieved because NT can fill the pores in DCM and its products can bind with particles. This results in formation of large aggregates owing to the small size, strong adsorption capacity and cation-exchange capacity.
期刊：
Transportation Safety and Environment,2020年2(1):3-17 ISSN：2631-4428
作者机构：
School of Civil Engineering, Changsha University of Science & Technology, Changsha Hunan, China;School of Traffic & Transportation Engineering, Changsha University of Science & Technology, Changsha Hunan, China;College of Materials Science and Engineering, Changsha University of Science & Technology, Changsha Hunan, China;Laboratory of Civil Engineering and geo-Environment, Lille University, EA 4515 LGCgE, F-59000 Lille, France
摘要：
Slope protection has always been a major concern in highway construction and later operation. Ecological protection technology is widely used in highway slope, which takes into account functions of protection, ecology, and landscape. Ecological protection technology is mainly to improve the stability of the slope through the combination of supporting structure and plants, and vegetation restoration can reduce the negative impact of highway construction. In this paper, the latest research progress of ecological protection technology was first reviewed to identify the main construction process and types, which revealed the protection mechanism of ecological protection technology. The comprehensive benefits of ecological slope protection technology were analysed from the aspects of air, water circulation, landscape and biodiversity. It has found that ecological protection technology of highway slope mainly forms the atmosphere-plant-soil system. Ecological protection technology of highway slope improved the stability of the slope through the supporting structure and the anchoring effect of plant roots. And the restoration of the surface vegetation on the slope promoted the photosynthesis and transpiration of plants and purifies the air quality along the highway. Ecological protection technology of highway slope could quickly restore the ecological balance, overall landscape and biodiversity of the region.
摘要：
Embankments filled with disintegrated carbonaceous mudstone (DCM) are prone to uneven settlements because of water-softening property and secondary disintegration of carbonaceous mud stone. To address this problem, nano-Al2O3 and cement were proposed in this study to improve the strength of DCM. Many nano-Al2O3-and cement-modified DCM (NACDCM) specimens with various nano-Al2O3 contents were prepared. Unconfined compression tests and triaxial compression tests were performed to examine the strengths of NACDCM under different conditions. Moreover, X-ray diffraction (XRD) analyses and scanning electron microscopy (SEM) observations were performed to reveal the microscopic mechanism for modification of the NACDCM. Macroscopic results showed that the unconfined compressive strength of NACDCM reached maximum when the nano-Al2O3 content was 0.2%. The cohesion showed positive correlation with nano-Al2O3 content while the angle of internal friction presented negative correlation with nano-Al2O3 content. Moreover, microscopic results indicated that nano-Al2O3 and cement improved the strength of NACDCM, mainly through cement hydration reaction pozzolanic reaction, ion exchange, gel effect and filling effect.
通讯机构：
School of Civil Engineering, Changsha University of Science & Technology, Changsha, China
关键词：
土质边坡;降雨入渗;入渗深度;饱和区
摘要：
采用饱和-非饱和渗流有限元计算理论,建立一维、二维模型,对不同降雨强度、土质类型、表面吸力以及边坡坡度下的边坡降雨入渗深度和饱和区变化规律进行研究。研究结果表明:对于同种土质而言,初始表面吸力越小,降雨入渗深度越大,降雨入渗深度从大至小对应的土质依次为粉土、砂土和黏土;在降雨过程中,黏土在降雨入渗深度范围内均为饱和区域,而粉土则先在入渗深度范围内出现饱和区,随后饱和区域消散,砂土首先在降雨入渗范围内形成饱和区,随后饱和区下移形成悬挂式饱和区;边坡坡度越大,边坡底部的降雨入渗深度越大,粉土边坡受坡度影响更明显;在降雨作用下,当初始表面吸力为100 k Pa时,砂土边坡表面生成饱和区,随后饱和区扩大并下移;而当初始表面吸力为10 kPa时,降雨会导致粉土边坡地下水位上升。
作者机构：
[史振宁; 付宏渊; 马吉倩] School of Traffic and Transportation Engineering, Changsha University of Science &, Technology, Changsha, 410014, China;[Zeng, Ling; 王桂尧] School of Civil Engineering, Changsha University of Science &, Technology, Changsha, 410014, China;[马吉倩] Highway Administration Bureau of Hunan Province, Changsha, 410016, China
通讯机构：
School of Civil Engineering, Changsha University of Science & Technology, Changsha, China
作者机构：
[付宏渊; 邱祥; Zeng, Ling] Key Laboratory of Road Structure and Material of Ministry of Transport, Changsha University of Science &, Technology, Changsha, Hunan, 410114, China;[邱祥; 唐昊龙; 付宏渊] School of Traffic and Transportation Engineering, Changsha University of Science &, Technology, Changsha, Hunan, 410114, China;[李光裕; Zeng, Ling] School of Civil Engineering and Architecture, Changsha University of Science &, Technology, Changsha, Hunan, 410114, China
通讯机构：
Key Laboratory of Road Structure and Material of Ministry of Transport, Changsha University of Science & Technology, Changsha, Hunan, China
作者机构：
[王平] School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China;[蒋朝晖] School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha, 410114, China;[何忠明; 付宏渊] School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha, 410114, China;[王琼] School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha, 410114, China
通讯机构：
[Wang, P.] S;School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha, China
