The gully land creation in the Loess Plateau has aroused widespread concern, but differential settlement of reclamation land seriously affects normal use of it. In order to clarify the differential settlement characteristics, numerical model of gully land creation is established to investigate different influencing factors by finite element method, and sensitivity analyses are performed by introducing the sensitivity coefficient. The numerical calculations show that the settlement curve is parabolic in which the excavation section rebounds and the fill section subsides. The settlement and settlement gradient are positively linearly correlated with the fill height, filling velocity, and water level difference; they are negatively linearly correlated with the number of filling layers. The maximum settlement of the V-shaped gully is smaller than that of the U-shaped gully, but the settlement gradient is the opposite. By the sensitivity analysis, the influence degree of four factors to settlement gradient was filling height at first, then filling layers, filling velocity, and groundwater level difference. To decrease the differential settlement, it is suggested that the open and gentle gullies should be selected in the design phase, the fill and excavation heights should be reduced as much as possible. Moreover, more layers and a slower filling rate can reduce the differential settlement of gully land creation. Overall, the numerical results offer some valuable references to improve the design and construction of gully land creation on the Loess Plateau.

In recent years, many levees have been widened to prevent flood in large rivers in China. In order to explore the stability of widened levee slope, the seepage analysis and slope safety factor calculation of widened levee under different conditions are carried out by building numerical models. The results show that the widened value has little effect on the stability of the waterside slope, but has a greater effect on the landside slope. When the widening value of new levee is 1, 2, and 3 times of old levee, the minimum safety factor of landside slope increase by 9.2%, 23.2%, and 37.4% respectively, and it has an approximate linear relationship with the widening multiple. Calculation shows different permeability coefficient ratios of new and old levees have little influence on the seepage gradient and slope stability of old levees, and have significant influence on those of new levees. The minimum safety factor of landside during the variation of the water level increased by 4.6% and 17.9% respectively when new levee permeability coefficient is 0.1 times and 16 times of old levee as the widening value of new levee is 3 times of old levee.

This study constructed driving simulation scenarios in order to determine the influence of a spiral tunnel’s radius on a vehicle’s operation speed and trajectory deviation at the design stage, and potentially reduce driving risk in spiral tunnels. Based on the 3D simulation cockpit and UC-win/Road software, got the corresponding driving speed and trajectory offset data under different working conditions, and the influence of spiral tunnel radius on vehicle operating characteristics under different working conditions were obtained through SPSS multiple nonlinear regression analysis. The research results show that as the radius increases, the speed variation coefficient gradually increases, and the vehicle lateral offset gradually decreases. Finally, based on the lateral offset limit value and the “self-explanatory” theory, the limit minimum radius, and recommended radius value range corresponding to the four working conditions are obtained.

Harmless treatment and resource utilization of wastes like fly ash have always been a social difficulty and a research hot spot in the field of pavement. In this paper, samples of fly ash generated from a coal-fired power plant in Yan’an City, Shaanxi Province were collected; and a desulfurized-high-calcium-fly-ash (DHCFA) was selected as the representative to be used for the alternative of traditional limestone fine powder (LFP) in asphalt mixture. Specifically, the chemical and physical characteristics of DHCFA and LFP were studied and compared firstly. Then the performance of asphalt mortar and asphalt mixture containing different amounts of DHCFA were further investigated. XRF and XRD results show that DHCFA and LFP both have significant alkalinity, and DHCFA has relatively richer chemical composition and phase distribution. TG-DSC results show DHCFA and LFP both satisfy the construction requirements on thermal stability. Asphalt mortar results showed DHCFA had the similar effect as LFP (control sample) on the whole. Asphalt mixture results revealed that the characteristics of DHCFA such as density, composition and compaction influence the performance of asphalt mixture. DHCFA could improve the low temperature performance and water stability of asphalt mixture, while reducing the high temperature performance and strength. Above results indicates that DHCFA could be used for mineral powder in asphalt mixture, however, its dosage should be carefully verified since it has adverse impact on the high temperature performance and strength of asphalt mixture.

Take typical widened levee for example, taking clay and arenosol serve as materials of old levee body and widing body, the paper uses numerical analysis software to calculate the seepage and deformation characteristics of widened levee under water level.The results show that the water content contour line is discontinuous at the intersection of the old and new levee body, the total water head contour line is rejected by the interface, and the water content and the total head appear sharply lower.Seepage slope significantly changed at the interface and widened subgrade toe.The maximum settlement of the widened levee appears at the shoulder of the new levee, and the settlement is related to the height of the water level.The vertical deformation of the levee foundation is saddle shaped.The lateral deformation of the widened levee shows the trend of the old and the new levee moving outwards.The change of the seepage field is caused by the difference of the new and old filling properties of the subgrade under the seepage action of river water.Deformation is caused by the influence of seepage field on the stress field under the effect of new levee self weight.

堤防道路涉及水利与交通2门学科,发挥着防洪和交通运输的双重作用.结合我国近年来堤防道路发展历程,在已建堤防道路工程概况基础上,总结我国堤防道路的建设特点:道路类型取决于地理位置,建设标准不断提高,道路功能逐渐扩展且设计更加灵活.阐述目前我国堤防道路建设在堤路结合形式、设计速度、功能分类分级体系、横断面形式、堤防加宽稳定措施、填筑材料和压实标准、堤基处理、路面防裂、管理和维护机制9个方面的技术进展,指出了仍需深化研究的3个问题,即堤防道路关键设计指标体系、加宽堤防的渗流稳定性和管理办法.

目前我国堤防道路在管理上存在缺乏横向协调机制、规划目标模糊、管理归属不明、限行措施不当、道路附属设施不完善和出入口设置不合理等问题.解决问题的关键是建立协调机制、明确堤防道路的功能、制定灵活的管理措施、建立堤防道路功能分类分级体系、合理设置上堤入口.提出了融入周边路网、充分发挥交通作用,转变建设思路、优化整合各类功能,结合当地特点、带动相关产业发展以及树立还岸于民、尊重自然理念的堤防道路发展设想.

A levee road is a component of a levee project. The subgrade of a levee road is the levee itself and usually it is submerged in the water. A special attention has been paid for slop stability and seepage of levee road under submerged condition during design and construction phases. This study investigated the effect of precipitation on humidity distribution in a levee road subgrade using the commercial finite element (FEM) package, GEO-Studio. The saturated-unsaturated seepage model has been adopted in the SEEP/W module to conduct numerical simulation on the humidity distribution of levee subgrade. Different ground water level on the river side was used. The effect of precipitation was also included. The humidity distribution in the simulated levee subgrade was presented through counter maps.

According to the characteristics of levee and road combined project, the paper analyzes problems of levee road. Design speed of levee road is determined by the main function, economy and safety. The paper studies the slope and the elevation of levee crest in "Code for Design of Levee Project", and compared it with road standard. The proposal was put forward, which includes: recommended values of cross slopes is 1.5%similar to 2.5%, minimum longitudinal gradient of crest is 0.3%, the corresponding position of the crest elevation on the cross section, the calculation of crest elevation should consider the thickness of pavement layers. Finally, an engineering example is cited, which can be used in the design of similar engineering reference argument.

为了解堤防道路路基湿度的变化规律,运用地下水渗流分析软件对不同水位和加铺路面结构后在一定降雨条件下的路基湿度进行数值计算.结果表明,水位高低对下部路基湿度的影响显著,路基受水位影响分为湿度饱和区和湿度渐变区.湿度饱和线随临水侧的水位升高而升高,临水侧路基湿度较背水侧大.降雨对上部路基影响显著,路基的湿度随着降雨历时而增加.这种湿度增加的趋势随着临水侧水位的降低在路基表层尤为显著.堤顶覆盖路面后,降雨主要影响裸露堤顶下的路基湿度,而对行车道下的路基湿度影响较小.

为科学合理的确定堤防边坡的坡比,使堤防工程满足现代水利的建设需求,提出稳定性、经济性、社会性、景观性作为堤坡方案选择的四个原则.根据以上原则,确定了九个影响因素,建立堤防边坡坡比的主客观综合评价模型,利用多属性决策全面评价堤防边坡的整体效益,并结合实例给出最佳堤防边坡坡比确定方案.工程实践表明,本文方法确定的堤防边坡较为合理,在保证堤防边坡稳定性的基础上,还能兼顾社会效益和沿线景观建设.

In this paper, we analyze the function of the levee road in order to ensure that it meets the actual needs of the development process. Levee road can be divided into four categories:flood control road, comprehensive road, traffic road, and landscape road. These four categories are proposed according to the main functions of the levee road, the level of levee project, the location where roads lie, and the relationship between it and local road network. Additionally, regarding to the level of dike and traffic volume, the levee road construction' s standards can be divided into two or three levels. Finally, we proposed a classification and grading system of levee road.

山西省灵石县骏马选煤厂地基为填土及基岩双层地基,工程钻探中发现,对以煤矸石为主的填土钻探较困难,针对这一问题提出用视电阻率测试的方法确定填土厚度.选择了三个测点进行了视电率测试,并在测点位置进行了工程钻探,通过对比分析总结出了基岩面深度与极距的关系,计算分析结果表明,这种测试方法具有较高的准确性,简单实用,有较好的发展前景.

Determination of the functions of levee road according to local conditions and definition of levee road property can not only provide guidance for the planning and construction of levee road,but also offer the important basis for comprehensive utilization of levee road.Considering the functional difference between ordinary road and levee road,this paper analyzes the existing problems in the functional classification of levee road based on the relevant national standard and construction situation of levee road in China in recent years.Moreover,this paper discusses the functions of levee road and proposes several principles and concepts on the functional classification of levee road.

以西北农林科技大学土木工程专业为例,在分析道路方向教学现状的基础上,根据土木工程专业的培养目标和要求,对于课程体系、实践教学、教学方法和教学手段进行了探讨,初步构建适合农林院校的土木工程专业道路方向的教学体系。

With geotechnical centrifugal schemes on uneven settlement at the cut modeling test, the to fill location of s treating effect of different geogrid reinforcement ubgrade is studied. By means of measuring the deformation and displacement at the test point on the surface of such subgrade, what role of the paving layers of the geogrid can play to improve the uneven settlement of the cut to fill subgrade and the stability of subgrad a whole is analyzed, as a result, the best treating scheme could be obtained according to the contrast tests. e as The test results show that, in connection with the uneven settlement of the cut to fill subgrade, the treating effect two layers of geogrid is superior to one layer, while that of one layer is superior to none of geogrid.

The characteristics of the natural conditions of along-stream lines as well as their advantages and disadvantages are introduced here,the basic principles of their route design and main contradictions to be solved in their layout are expounded,and the route selection schemes of valleys are enumerated.At the same time,the route selection schemes for the secondary highway's along-stream lines with the designed velocity being 60 km/h are discussed in detail,so as to provide references for the route selection of along-stream lines in the future.

The compressive strength of steel fiber reinforced concrete depends not only on material component and mixing proportion but also on environmental factors as well as age.With a Contrast experimental investigation on time-varying regularity of compressive strength of steel fiber reinforced concrete in different circumstances,it is tested the compressive strength of steel fiber reinforced concrete cubes by different ages,which are separately put in standard curing condition,natural setting and simulated sea condition.The test results show that the compressive strength of steel fiber reinforced concrete in different circumstances increases always with the extension of age.However,it is various in different conditions,especialy in soft water corrosion,whose amplification of compressive strength is on the small side,influenced obviously by environmental factors.

Chloride ion content is an important factor affecting the durability of steel fiber concrete.In order to fully understand the diversification of chloride ion content in steel fiber concrete in different environments,concrete specimens are put in 3 different environments called as standards environment,natural environment and simulated sea water corrosion environment,then regular testing of chloride ion content is done.The results show that: in 3 different environments,the content of chloride ions in steel fiber concrete has a trend of increasing and,in earlier period,the increase in chloride ion content of the concrete is significant,the growth rate is significantly higher than other stages of the identical environment;the change in chloride ion content is almost the same in standard and natural environments;Different ages on the test specimens' change in chloride ion content in the same environment can be divided into four stages and have a significant periodic characteristics.

《道路工程》是土木工程专业的一门重要专业基础课,具有很强的实践性。本文针对《道路工程》课程教学中存在的一些问题,探讨用一些新的教学方法与教学手段来提高学生的学习效率,培养学生的综合应用能力。