矩形顶管关键技术研究现状及发展趋势探讨

首先，对矩形顶管技术的发展历程及其国内外研究现状进行综述，介绍当前矩形顶管技术主要的应用场景，并结合顶推力预测、注浆减阻、背土效应演化机制和控制对策、顶进过程中的地层响应模式和沉降计算、工作面稳定性评估等关键技术问题，对矩形顶管的理论研究进展进行回顾和讨论。其次，根据矩形断面掘进机的结构形式和切削方式，对国内外矩形顶管掘进机的开发现状及其分类进行介绍。最后，归纳当前矩形顶管在装备及工程应用领域面临的技术挑战，探讨矩形顶管技术的发展趋势，对矩形顶管装备智能化，矩形曲线顶进，长距离、大断面及复合地层等复杂场景下的矩形顶管技术进行展望。     

基于线性叠加的智能船舶经济性评估模型构建

经济性是智能船舶能否实现推广应用的关键,目前国内外有关智能船舶经济性分析的研究较少。本文通过对传统船舶经济性分析方法进行修正优化,提出智能船舶经济性分析计算模型,并根据理论推导结果,得出智能船舶经济性分析的线性叠加简化模型,并利用40万吨级VLOC实际运营数据进行科学性检验。本文提出的模型与方法适用于各类智能模块加装情况下的经济性核算,为相关单位开展智能船舶经济性快速分析提供了理论支持和解决方案。     

Widening the Panama Canal and U.S. ports: historical and economic impact analyses

ABSTRACT

The economic history of the U.S. illustrates how the role of many cities has been changed by being seaports or located on navigable rivers or lakes. Based on the widening of the Panama Canal in 2016, the West Coast ports that include the west coast seaports of California, Oregon, and Washington were expected to become less important, while the freight shares of the East Coast and Gulf ports would increase. By how much it has been not easy to measure or predict so far, but this study attempted to define some of the key parameters in the measurement. As well as several relevant background topics, both the demand- and supply-side versions of the National Interstate Economic Model, have been applied for the measurement of economic impacts. U.S. port authorities and policy makers at the local and national levels who respond and develop plans for coping with the new realities of the Panama Canal are able to understand the extent to which changes in shippers’ and land-mode transporters’ behaviors would undermine the logistics and the costs of their activities. Therefore, this study is important for a diverse spectrum of port development strategies in the U.S. to respond to the Canal expansion.     

考虑围岩蠕变特性的TBM隧道管片衬砌受力特性研究

为研究深部高地应力岩层中修建TBM隧道时管片衬砌结构的力学行为,以某深埋TBM工法隧道为研究对象,建立基于围岩蠕变和管片分块效应的衬砌-围岩复合模型,研究考虑时间效应下管片衬砌的受力特性。结果表明:考虑围岩蠕变效应下管片衬砌受力表现出明显的时间效应。随着围岩蠕变时间的延长,管片衬砌的形变、内力和接缝张开量均呈现两阶段增长,具体表现为前期呈线性增长,后期增加趋缓。洞周围岩应力经历三阶段变化,即先减小后增大直至稳定。围岩蠕变时间为100年时,管片衬砌的内力和形变量均接近极限值。研究结果可为深部高地应力且考虑围岩蠕变效应下的TBM隧道衬砌结构设计提供参考。     

Integrated models of land use and transportation for the autonomous vehicle revolution

ABSTRACT

The advent of the autonomous vehicle (AV) will affect not only the transportation system, but also future patterns of land development. Integrated land use and transportation models will be critical tools in assessing the path forward with this technology. Key questions with respect to land use impacts of AVs arise from potential changes in sensitivity to travel and reduced demand for parking. It is an open question whether AVs will induce urban sprawl, or whether spatial economies of agglomeration will mitigate any reductions in travel time sensitivity. The deployment of shared fleets of AVs would likely reduce parking demand, producing yet to be explored impacts on property development within existing urban footprints. We perform a critical assessment of currently operational models and their ability to represent the adoption of AVs. We identify the representation of time in such models as a vital component requiring additional development to model this new technology. Existing model applications have focused on the discrete addition of new infrastructure or policy at a fixed point in time, whereas AV adoption will occur incrementally through time. Stated adaptation surveys are recommended as tools to quantify preferences and develop relevant model inputs. It is argued that existing models that assume comparatively static equilibrium have been convenient in the past, but are insufficient to model technology adoption. In contrast, dynamic model frameworks lack sufficient structure to maintain reasonability under large perturbations from base conditions. The ongoing advancement of computing has allowed models to move away from being mechanistic aggregate tools, towards behaviourally rich depictions of individual persons and firms. However, much work remains to move from projections of existing conditions into the future, to the evolution of the spatial economy as it evolves through time in response to new technologies and exogenous stresses. Principles from complex and evolutionary systems theory will be important in the development of models with the capacity to consider such dynamics.     

3洞小净距隧道围岩压力计算方法

针对3洞小净距隧道围岩压力计算问题,基于普氏平衡拱理论,将围岩压力看作单洞隧道的基本压力与相邻隧道开挖引起的附加压力之和,提出适用于3洞小净距隧道的围岩压力计算方法;根据该计算方法研究不同岩柱厚度、开挖跨度和开挖高度对围岩压力的影响规律,并将该计算方法应用于确定八达岭长城站3洞小净距隧道围岩压力。结果表明:随着岩柱厚度的增加,围岩压力不断减小,当岩柱厚度达到某一值时,围岩压力与单洞隧道相同;岩柱厚度、边洞跨度和中洞高度变化影响整体围岩压力,中洞跨度和边洞高度仅影响各自单洞围岩压力;3洞小净距隧道的最优开挖顺序为"先边洞、后中洞",中洞围岩压力大于边洞,应力值最大点为中洞顶部。施工中应注意中洞围岩稳定,采取有效的措施对岩柱区域进行加固。     

造船经济论证方法的探讨

船舶经济分析是船舶技术经济论证的主要环节之一,但传统的造船经济论证方法存在着一定的缺陷。为此,充分考虑各个因素的不确定性,考虑经营的风险性,对传统的造船经济论证方法加以综合改进,形成新的造船论证方法——计算机模拟方法。与传统方法相比,计算机模拟的方法在最终结果的处理上更有现实意义。     

从温州经济模式学到的经验

叙述了温州经济模式的发展 ,并总结了温州模式的思想精髓     

火箭炮特定终点效应的概率研究

简要分析了火箭炮在现代战争中的作用，提出了利用新技术后的火箭炮可以实现特定终点效应的观点，并以近似直线终点效应为基本模型；分析了相邻两发弹杀伤区域的重叠条件，进而引入并推导了有效重叠长度的计算公式，结合蒙特卡罗方法对基本模型的有效重叠长度的概率问题进行了理论计算。结果表明，利用火箭炮形成特定的终点效应是可能实现的，算例在零系统误差、7mrad系统误差时形成的近似直线终点效应的概率分别为87．1％和10．3％。因此，提高密集度、系统误差、有效杀伤半径等因素的综合指标，是提高火箭炮特定终点效应概率的关键所在。     

通货膨胀对企业所得税及投资效果的影响分析

给出了通货膨胀影响企业所得税及投资效果的分析计算方法，弥补了一般项目投资技术经济分析不考虑通货膨胀因素影响的不足。