桥下开挖地铁对地道桥结构的影响

借助大型有限元分析软件 ,探讨大跨度斜交地道桥底板下开挖地铁对地道桥结构的影响。通过对开挖地铁前、后地道桥的受力和变形分析 ,得出不影响地道桥安全受力状态的最小开挖深度。

改善既有线顶进涵线桥接合部轨枕空吊状况的对策初探

既有线顶进涵箱体两侧线桥接合部的轨枕空吊病害是目前平改立施工给线路造成的一种普遍的而且较难解决的病害。文章分析此种病害的产生原因并提出整治措施。对比试验结果表明 ,整治效果很好。

软土地基大体积箱涵顶进施工技术

顶进施工方法的特点是在保证铁路交通安全运行的前提下，用设备将铁路外预制的钢筋混凝上箱涵顶入铁路路基内。形成与铁路的立交地道桥。文章以中央大道工程新港四号路地道项目下穿疏港二线铁路箱涵顶进施工为例，介绍在软土地基上完成大体积混凝土箱涵顶进的施工技术。

论铁路桥涵顶进施工技术

近年来,随着铁路运输能力的提高,列车运行速度的加快和城市建设发展对安全的需要,桥涵顶进施工项目极为普遍。但是,因为既要保证列车运行安全,又要保证施工顺利进行,二者之间的干扰不可避免,加上列车通过时的振动和气象的变化对开挖路基影响可能导致土体失稳,顶进施工环境复杂,立体交叉作业多,极易导致箱体移位、路基坍塌、人员跌落打击等,最终酿成事故。本文针对施工过程中容易出现的事故类型,笔者根据自己多年的施工经验阐述了施工中的技术及防护措施,希望对同类工程施工有所帮助。

浅谈DN2600暗涵顶管施工工艺

文章以百色市新兴路DN2600暗涵顶管施工为例,介绍了泥水平衡式顶管施工方案与顶进施工工艺,指出该施工方法安全、稳定、可靠,可在涵道顶进线路控制工程中取得良好的施工效果。

浅析道路下穿既有铁路箱型框架桥顶进法施工

随着我国经济与社会的发展，急需发展城市之间的交通网络体系，使这些城市连成一体。在实际工程中，许多工程都会穿越已有公路或铁路系统，当线路与城市干道平面交叉时，工程的施工对交叉口的干扰很大，因此，本文进行道路下穿既有铁路箱型框架桥的施工研究，将具有重要的理论与实践意义。

Binary Bell Polynomials,Bilinear Approach to Exact Periodic Wave Solutions of(2+l)-Dimensional Nonlinear Evolution Equations

In the present letter, we get the appropriate bilinear forms of （2 ＋ 1）-dimensional KdV equation, extended （2 ＋ 1）-dimensional shallow water wave equation and （2 ＋ 1）-dimensional Sawada -Kotera equation in a quick and natural manner, namely by appling the binary Bell polynomials. Then the Hirota direct method and Riemann theta function are combined to construct the periodic wave solutions of the three types nonlinear evolution equations. And the corresponding figures of the periodic wave solutions are given. Furthermore, the asymptotic properties of the periodic wave solutions indicate that the soliton solutions can be derived from the periodic wave solutions.

Binary Bell Polynomials Approach to Generalized Nizhnik-Novikov-Veselov Equation

The elementary and systematic binary Bell polynomials method is applied to the generalized NizhnikNovikov-Veselov (GNNV) equation.The bilinear representation,bilinear B&cklund transformation,Lax pair and infiniteconservation laws of the GNNV equation are obtained directly,without too much trick like Hirota’s bilinear method.

Study on Project Progress Curve Model

Because of the discrepancy of project types,the project progress curves present different characteristics.Studying project progress curves can reduce management risk of project and overall grasp the enforcement condition of the project.Combining project characteristic,this paper reaches 4 kinds of project progress curve patterns.If the front of the progress curve is concave,and its rear is protruding in the break point,it is named as S model.If its front is protruding and its rear is concave in the break point,it is named as the reverse side of S model.If the front and rear are concave in the break point,it is named as J model,and two half sections are both upward protruding,it is named as the reverse side of J model.Through a case study,it shows that application project progress curve model can better raise project management.

Frequent item sets mining from high-dimensional dataset based on a novel binary particle swarm optimization

A novel binary particle swarm optimization for frequent item sets mining from high-dimensional dataset(BPSO-HD) was proposed, where two improvements were joined. Firstly, the dimensionality reduction of initial particles was designed to ensure the reasonable initial fitness, and then, the dynamically dimensionality cutting of dataset was built to decrease the search space. Based on four high-dimensional datasets, BPSO-HD was compared with Apriori to test its reliability, and was compared with the ordinary BPSO and quantum swarm evolutionary(QSE) to prove its advantages. The experiments show that the results given by BPSO-HD is reliable and better than the results generated by BPSO and QSE.

Delay Analysis Techniques Comparison

Many techniques have been used in the courts to demonstrate the criticalities of a delay event on the project schedule. At this time, there is no standard method to analyze a delay claim. This paper first introduced a fictional case study that has most types of delay and acceleration events that might be faced on a real project. The case study is applied to all current techniques of delay claims that have been identified from previous studies. The comparison uses the delay claim issues as criteria to evaluate all the delay claim techniques from the case study results. The case study result and discussion demonstrate that the Day-by-Day technique satisfies all the desired criteria while other techniques lack some.

The trend of mechanizing road header for coal mine entry

In discussing coal mine entry construction with rock bolt technology, examinedthe craft and machinery problems as well as the conditions in which to use each kind ofmachine and tool.It exposed the intrinsic flaws of the widely used road header.The problemis that it was designed according to early timbering support state but is not suitable forrock bolt technology.The way to improve the function of existing road headers is notthrough parallel operations but using the SUDM (Shield Union Driving Machine), which isa new machine that improves construction.This article proposed a few solutions in designto solve this problem.

Vibration sensitive admixture for roller compacted concrete

In order to further speed up the construction progress,shorten the rolling time and reduce the rolling times of roller compacted concrete after analyzing work of construction progress improvement measures of roller compacted concrete,research on vibration sensitive admixture is carried out and satisfactory results are acquired.The new type vibration sensitive admixture was used in the project of Jinghong hydropower station in Yunnan Province,China.The engineering experimental results show that various indexes have been verified.Meanwhile,the compactness of roller compacted concrete is improved under the same rolling times,the rolling times and the duration time can be reduced under the same compactness requirement in construction practice.

Framework for Quality Improvement of Infrastructure Projects

In order to achieve high quality that not only gives acceptable return value to society but also satisfies the needs of all the stakeholders of infrastructure projects, comprehensive understanding of issues pertaining to the quality of the project is needed. The aim of this study is to provide an overview the most common procurement methods used in constructing infrastructure transport projects and analyze how these methods contribute to the desired quality of the final product in relation to client competence. An on-line survey of construction actors was carried out to ascertain quality level of Swedish infrastructure transport projects and determinant factors of quality problems. An equal number of respondents indicated that the quality of infrastructure projects has either increased or remained same level over the past twenty years. Respondents also pointed out lack of client competence that is vital in realizing the desired quality level through proper procurement, monitoring and evaluation procedures. Public clients heavily rely on traditional design-build procurement that requires considerable client involvement of a project. Thus, the association of quality problems and lack of client competence may not be a mere coincidence but an overlooked outcome of current situation.

Does Anyone Benefit？ - A Quantitative Effect Analysis on US Punitive Tariffs on Chinese PV Imports from a Global Perspective

Financial support from National Science Foundation for Distinguished Youth （Grant No.70925006）, National Natural Sciences Fund Program （Grant No.71103059）, Humanities and Social Sciences Youth Program of the Ministry of Education （Grant No. 10YJC7902930）, is gratefully acknowledged. Authors highly appreciate the comments of anonymous reviewers and take sole responsibility for this paper.

A Ternary 4-Point Approximating Subdivision Scheme

In this paper, the author presents a class of stationary ternary 4-point approximating symmetrical subdivision algorithm that reproduces cubic polynomials. By these subdivision algorithms at each refinement step, new insertion control points on a finer grid are computed by weighted sums of already existing control points. In the limit of the recursive process, data is defined on a dense set of point, The objective is to find an improved subdivision approximating algorithm which has a smaller support and a higher approximating order. The author chooses a ternary scheme because the best way to get a smaller support is to pass from the binary to ternary or complex algorithm and uses polynomial reproducing propriety to get higher approximation order. Using the cardinal Lagrange polynomials the author has proposed a 4-point approximating ternary subdivision algorithm and found that a higher regularity of limit function does not guarantee a higher approximating order. The proposed 4-point ternary approximation subdivision family algorithms with the mask a have the limit function in C2 and have approximation order 4. Also the author has demonstrated that in this class there is no algorithm whose limit function is in C3. It can be seen that this stationary ternary 4-point approximating symmetrical subdivision algorithm has a lower computational cost than the 6-point binary approximation subdivision algorithm for a greater range of points.

Present situation and improving measures of Chinese Construction Engineering Management informatization

Building engineering management is a huge and complex work, which the key to ensure the quality ofconstruction projects. With the rapid development of the domestic construction industry, the traditional engineering management model can not meet the needs of a large number of construction project information exchanges. Only realizing informationization of construction engineering management, can reduce the cost of construction projects, improve the efficiency of project management and construction progress. This paper analyzes the current situation of construction management informatization, and puts forward some suggestions to strengthen the construction management information construction.

Global Asymptotics of Krawtchouk Polynomials——a Riemann-Hilbert Approach

In this paper, we study the asymptotics of the Krawtchouk polynomials Kn^N（z;p,q） as the degree n becomes large. Asymptotic expansions are obtained when the ratio of the parameters n/N tends to a limit c E （0, 1） as n →∞. The results are globally valid in one or two regions in the complex z-plane depending on the values of c and p; in particular, they are valid in regions containing the interval on which these polynomials are orthogonal, Our method is based on the Riemann-Hilbert approach introduced by Delft and Zhou.

Detection of schedule delay risk of empirical construction projects

In Ethiopian construction projects, schedule delay risk is a predominant issue because it is not properly addressed. Although several studies have been focused on the various effects of risk in construction projects, limited efforts have been made to investigate the typical and the overall schedule delay risk. In this study, our aim is to detect the typical and overall schedule delay risk throughout the construction project lifecycle, which consists of the pre-construction, construction, and post-construction stages, and compare the stages with each other. Common criteria, sub-criteria, and attributes were developed for all alternatives for the purpose of making a risk decision. The methodology that was followed integrated the multiplecriteria decision-making(MCDM) model of fuzzy analytic hierarchy process comprehensive evaluation(FAHPCE)and the relative important index(RII). Data were collected from 77 participants, who were selected through purposive sampling from different contracting organizations in Ethiopian construction projects by means of questionnaires that were distributed to experienced experts. The findings showed that there is a typical delay risk either in the type or in the level of the different construction activities.Consequently, the most influenced alternative is the construction stage because of the high-risk responsibility,resource, and contract condition related criteria. The postconstruction stage was the second most influenced stage because of the high-risk responsibility-related criteria. The pre-constructed stage was the least influenced stage that consist high-risk criteria of responsibility, resource, and contract condition related. These differences provided noteworthy information about risk mitigation in construction projects by identifying the exact risk level on specific activity to make appropriate decision.

Some 3-adic congruences for binomial sums

We prove some 3-adic congruences for binomial sums,which were conjectured by Zhi-Wei Sun.For example,for any integer m≡1（mod 3）and any positive integer n,we have v3（1/n ∑n-1X k=0 1/mk 2k/ k〉））≥min{3（n）,3（m-1）-1},where 3（n）denotes the 3-adic order of n.In our proofs,we use several auxiliary combinatorial identities and a series converging to 0 over the 3-adic field.