Features Desired in Public Transport in a Developing City: Users’ Perspective

Excessive growth of population and urbanization in the developing countries set an increasing demand of mobility services. To meet this demand, public transport plays a significant role by providing an easy and affordable mobility service. Public transport service is a process evolving over time nevertheless is not always directly responsive to the changing demand of the passengers. Recently in developing countries, the unpleasant experience in public transport services is seen as one of the main reasons behind increased passenger car share, which eventually lead to traffic congestion. However, the situation can be ameliorated if the features of the public transport are improved by addressing the users’ demand. In this study, the primary features desired and demanded by the passengers of a developing country are identified by three phase survey. These identified features are also categorized based on public responses. And finally, the required features in an appropriate public transport mode are prioritized by using a common Multi Criteria Decision Making approach (AHP—Analytic Hierarchy Process). The study suggests that residents of the developing city are not that much concern on the outlook and ambience of the service rather they are concerned about finishing their trips safely in time at an affordable rate. The findings of this research will help planners and decision makers to make the best use of the investment in public transport services and infrastructure to promote these modes over privately owned vehicle.

未来商业融合体——多元共生、跨界融合

商业建筑作为一种建筑类型,经历了漫长的历史变迁与演化。近20年来,国内商业建筑实践大多以商业综合体为主,其优劣势已经过业界的充分检验。在如今飞速迭代的社会、经济、科技环境下,商业综合体面临新的机遇与挑战。本文从深耕商业建筑设计领域多年的建筑师视角出发,提出“商业融合体”这一改良概念,并对未来商业的特征和特点进行分析和预判,认为“多元共生、跨界融合”将是商业建筑的发展方向和主流趋势。

Numerical study of hydrodynamic mechanism of dynamic tidal power

Dynamic tidal power is a new way of capturing tidal energy by building a water head using a dike perpendicular to the coast. This study explored the hydrodynamic mechanism of the water head across an intended dynamic tidal power dike system using the Delft3 D-FLOW software module. The propagating wave was simulated in a rectangular domain with a horizontal sea bottom at a 30-m depth. A significant water head was created across the dike by blocking the water. The water head increased with increasing dike length and increasing undisturbed tidal current acceleration. The maximum water head for the dike with a length of 50 km, located 900 km from the western boundary, was 2.15 m,which exceeded the undisturbed tidal range. The time series of the water head behaved in a manner identical to the undisturbed tidal current acceleration. The distribution of the water head over the dike assumed an elliptical shape. A parasitic wave was generated at the attachment and scattered outward. The phase lag across the dike did not behave as a linear function of the detour distance.

Study of Mutual Improvement of Completed Weathered Phyllite and Red Clay Based on Neutralization Effects of Swelling and Shrinkage Deformation

Completely weathered phyllite(CWP)soil is a kind of special soil with high swell potential,while red clay is a special soil with high shrinkage.This means that these two kinds of special soils are usually not suitable for direct use as subgrade fill.To reduce the swell index of the CWP soil and the shrinkage of red clay at the same time,it was proposed to blend the CWP soil with red clay to improve their basic characteristics.A series of swell index tests and dry-wet cycle tests of the blended soils have been carried out at varying blending ratios,compaction coefficients and moisture contents.The test results show that the free swell index of the blended soil decreases with the increase of red clay,moisture content and compaction coefficient,respectively.The fissure density of the blended soil first decreases and then increases with the blending ratio,with the lowest being zero when the blending ratio is ranging from 20%to 40%.Through particle microscopic analysis and elemental composition analysis,it is found that the neutralization effect,the dilution effect of swell minerals,and the partition effect of coarse particles play an important role in restraining expansion and shrinkage deformation of the blended soil.Based on the liquid limit requirement of Chinese Railway Design Code(TB 10001-2016),the optimal blending ratio of red clay has been proposed to be 50%.Compared with the CWP soil,the free load swell index of the blended soil is reduced by 45.0%and the fissure density is reduced by 99.3%compared with that of red clay.Therefore,it is feasible to improve the CWP soil by blending it with red clay at an optimal ratio of 50%by using the neutralization effect of the expansion of CWP and shrinkage of red clay.

新冠疫情下“不可抗力”再思考及其应用建议

对比国内及国际主流标准施工合同条件内"不可抗力"相关条款,对比"不可抗力"事件及与其相关的"情势变更"及"意外事件"两类事件在判定及责任划分方面的异同,对"不可抗力"事件进行再思考,进而在一个相对宏观却又深入的层面上揭示"不可抗力"的判定标准及责任划分的内在原理。在再思考的基础上,给出"新冠"疫情下,建设工程常见索赔的定性的处理建议。

Grain Size Distribution of Soils within the Cordillera Blanca, Peru: An Indicator of Basic Mechanical Properties for Slope Stability Evaluation

This paper presents results of a study on the mechanical properties of sandy and gravely soils within the Cordillera Blanca, Peru. The soils were divided into groups according to their origin(glacial, fluvial, or debris flow). The grain size distribution of forty three soil samples was used to classify the soils according to the scheme of the Unified Soil Classification System(USCS). These distributions have then been used to estimate shear strength and hydraulic properties of the soils. There are clear differences between the soils which reflect their divergent origins. The glacial soils normally fit within one of two distinctive groups according to the proportion of fines(Group A, 7%-21.5%; Group B, 21%-65%). The estimation of shear strength at constant volume friction angle and peak shear strength of the glacial sediments with low content of fines was made using published data relating to the measured shear strength characteristics of soils with similar origins and grain size distributions. The estimated values were supported by measurements of the angle of repose taken from fourteen samples from two moraines and by shear tests on samples from one locality. The results of the grain size distribution werealso used to estimate the average hydraulic conductivity using the empirical Hazen formula which results were verified by field infiltration tests at two localities.

Stability Problems in Road and Pipeline Constructions and Their Mitigation——Examples from Sakhalin and Azerbaijan

The paper gives two examples of larger construction projects with typical stability problems. The first example is from Sakhalin Island in the Russian Far East. It is connected with a construction of oil and gas pipelines through the mountainous terrain in Makarov region. The region has an active geotectonic history and is highly affected by uncontrolled erosion and extensive landslips. Basic principles of landslide hazard mitigation are presented. The second example is from a motorway construction in Azerbaijan. This motorway leads from Baku to Russia through a seismo-tectonically active area at the toe of Caucasian mountains and in some places is situated in deep cuts at the toe of high slopes. This unsuitable routing, together with seismic activity, led to a slope stability failure of a slope affected by recent tectonic movements near the village of Devechi. Stability conditions and designed remedy measures are presented.

Experimental Study on Improvement Effects of Completely Weathered Phyllite Using Red Clay and Cement for High-Speed Railway Embankments

Completely weathered phyllite(CWP)has the characteristics of difficult compaction,low shear strength after compaction and large settlement after construction.The traditional improvement method using a single agent of red clay or cement for CWP satisfies the subgrade requirements for ordinary railway,but cannot meet the requirements of immediate strength and long-term post-construction settlement of high-speed railway at the same time.A series of experimental investigations were undertaken for the blended CWP soils,with three additives used.The first additive was red clay,the second was cement and the third was a combination of both red clay and cement at various portions.Results of consolidation test and shear strength test carried out for the treated CWP soils show that:1)The effect of cement on improving the compression modulus of CWP is much better than that of red clay;2)The settlement of an embankment of 10 m high formed by blended soil of CWP with 3%cement can be controlled within 15 mm,while the settlement will be 25.15 mm for the same embankment of blended soil of CWP with 40%red clay;3)The shear strength and ultimate bearing capacity of CWP improved by red clay are much better than those of 5%cement;4)The ultimate bearing capacity of CWP improved by 40%red clay is 3.42 times of that by 3%cement and 2.95 times by 5%cement.Furthermore,the bearing capacity of CWP when improved by red clay can meet railway subgrade requirements immediately after compaction,while cement improved CWP needs a curing time of 1 day or longer.This is an impediment to rapid construction process.The improvement mechanism of red clay is mainly filling effect and grading improvement effect,while the improvement mechanism of cement is mainly hardening reaction,which produces high strength material to cement.It is found that 40%red clay and 3%cement treated CWP,which is considered to be optimum,can meet the subgrade requirements of both immediate bearing capacity and long-term post-construction settlement for the high-speed railway.

捷克地下储存系统基岩的不稳定性问题（英文）

地下储存系统在全球范围内在地热能、或放射性废物处置方面正用于天然气(CH_4)地质储存、CO_2地质处置。我们引入一个复杂的方法检测在深地质地下储存库基岩不稳定性所带来的风险。有关地下空洞引起的基岩不稳定性的研究和讨论了许多年。在捷克的波希米亚地块(中欧)在地质和构造上均很复杂。长期的地质和采矿研究,自然和诱发地震、氡的放射,和花岗岩的性质为在捷克放射性废物处置的潜在存储地提供了有用的信息。另外,捷克,140 Bq m^(-3)平均浓度氡是世界上平均氡浓度最高的。基岩不稳定性可能从微观特征的出现,如粒度、矿物的取向,和微裂缝。任何地下储存设施的建设必须考虑储存的物质和地质背景。在捷克,花岗岩和花岗岩是最好的地下储存地。微裂缝网络与及其迁移是岩石特殊情况,其变化甚大。此外,基质的孔隙度也影响岩石的机理。任何地下存储网络位置的选择必须十分仔细。作者认为,一个特定地点研究一组复杂的参数要从微观到宏观,岩石类型以确保在施工、操作过程中以及封闭后存储仍然是安全的,稳定的。

Detection Tool for Unbalanced Bids

Unbalanced bidding is a cash flow management strategy that is recognized as an illegal/disqualifying practice by public owners;and unethical practice by most private owners. This practice provides the awarded bidder with unjustified advantages at the expense of the owner. Unfortunately, limited tools and techniques are currently available to identify and detect unbalanced bids during the evaluation process. This paper presents an innovative detection tool to identify unbalanced bids in unit price contracts during the bid evaluation process. The proposed technique develops BMDI graphs to visualize total markup variation patterns during the project lifetime to detect unbalanced bids. The proposed method also uses Monte Carlo simulation to take in consideration the impact of cost uncertainties and risks. An illustrative example was presented to show the capabilities and features of the proposed method in determining the status of submitted bids during the evaluation process.

A methodology for calibration of traffic micro-simulator for urban heterogeneous traffic operations

Traffic micro-simulation is a widely accepted tool in many countries for the evaluation and assessment of alternative design schemes.However,for several developing countries,replicating heterogeneous,non-lane based traffic in a micro-simulation framework is gaining increased importance and still remains a challenge due to its complexity.The present study demonstrates a methodology to calibrate a traffic micro-simulation model giving due consideration to vehicle-class specific driver behavior in an urban Indian scenario for a midblock section and an intersection approach in Kolkata.The sensitive parameters affecting the driver behavior were identified for every vehicle type using Latin Hyper cube design,taking vehicle class specific travel time as a performance measure.Linear regression models were developed for each vehicle class considering the sensitive driving behavior parameters.The models highlight that the dependency of measure of effectiveness(MOE)of one vehicle type is not only limited to its own driver behavior but also on parameters of other vehicle classes.A genetic algorithm based optimization was adopted to obtain optimal parameter sets for different vehicle classes.The optimum values were found to vary significantly across all vehicle classes at a 95%confidence level.Single and multi-criteria calibration principles are also implemented to yield much more realistic results and subsequently minimizing weighted error for all vehicle classes.