沥青稳定基层混合料抗变形能力试验研究

在分析含沥青稳定基层结构的全厚式沥青路面温度特性基础上，得出沥青基层混合料性能试验的合理温度，结合蠕变试验，分析了温度和级配对沥青基层混合料抗永久变形能力的影响，结果表明骨架密实级配比连续级配抗永久变形能力强。     

Analysis of deformation of rotor and influence on the performance of gyro based on B-spline wavelet FEM

Some construct characteristics and composing material of the new Gyro＇ s rotor are introduced. Some factors resulting in deformation of the rotor surface are analyzed. Under different loads such as the fo,＇ce of deflecting center, the change of temperature, the fo,ce of pressure and couple factors, the deformation of rotor is analyzed with the wavelet finite element simulation software. The vector distributing map of rotor reformation is given. The deformation resulting from the pressure force of photon is studied. Finally, the influence on Gyro＇ s performance because of anomalous surface of rotor due to deformation of rotor is researched and the result is useful to forecast the performance of the drift of gyroscope. The disturbing moment resulting from the deformation of rotor can be compensated using the mathematic method, and provides an important reference for both design and optimization of the rotor.     

砂砾地层电力顶管施工引起的地面变形研究

文章针对砂砾地层电力顶管施工引起的地面变形开展研究。首先,基于现有散粒土的沉降理论计算公式,进行某砂砾地层电力隧道顶管施工引起地面变形的理论计算和分析;其次,通过理论分析和现场实测,得到砂砾地层顶管施工引起的地面变形规律;最后,在现有理论计算公式和监测数据的基础上,利用规划求解,提出适用于砂砾地层顶管施工引起地面变形的沉降槽宽度系数计算公式。研究结果表明,土体损失是引起地面沉降的主要影响因素,沉降计算时必须考虑土体损失在顶进过程中的动态变化;修正沉降槽宽度系数计算公式能够较好地适用于砂砾地层中顶管施工引起的地面沉降计算。     

大体积混凝土裂缝成因及防治措施

控制和预防大体积混凝土裂缝是一项系统工程,涉及到设计、原材料的选择、施工工艺、养护和其他一些不确定的因素。对大体积混凝土裂缝成因进行系统的理论研究,提出合理的裂缝控制措施,可为工程实践提供指导。     

永临结合的初期支护侵限处理方法

文章结合RAS RMEL隧道工程实例,介绍了国外铁路隧道软弱围岩大变形段初期支护的侵限处理方法.该施工方法是通过加强监控量测,及时发现支护结构变形量的增大情况,并立即进行支护的加强,如复喷混凝土、施作系统锚杆及锁脚锚杆等.当发生塑性变形的区域较大时,先采取在拱部安装临时钢管横撑,并及时施作仰拱封闭的处理措施,控制支护变形；后对待处理区进行加固,并根据设计图纸的要求跳槽开挖梯形槽,施作初期支护,然后再施作防水层；最后,用模板台车施作二次衬砌.实践证明,该永临结合的处理措施较一般处理措施具有施工简单、安全、节约成本等特点,尤其适用于地质条件较差和工期较紧的工程项目.     

地铁安全监测中基于三维激光扫描技术的隧道形变分析方法

基于三维激光扫描技术所获地铁形变监测数据的海量点云特性,提出隧道形变分析新方法。详细阐述了建立参考系、点云分割、格网化、差值计算、形变分析等步骤,并以正在监测的地铁隧道为例进行试验分析。试验分析结果发现:隧道形变分析新方法能确定隧道形变位置和形变大小,并将结果直观显示出来,能有效地衡量隧道形变。     

An efficient FE computation for predicting welding induced buckling in production of ship panel structure

In a Thermal-Elastic-Plastic (TEP) FE analysis to investigate welding induced buckling of large thin plate welded structure such as ship panel, it will be extremely difficult to converge computation and obtain the results when the material and geometrical non-linear behaviors are both considered. In this study, an efficient FE computation which is an elastic FE analysis based on inherent deformation method, is proposed to predict welding induced buckling with employing large deformation theory, and an application in ship panel production is carried out. The proposed FE computation is implemented with two steps:(1) The typical weld joint (fillet weld) existing in considered ship panel structure is conducted with sequential welding using actual welding condition, and welding angular distortion after completely cooling down is measured. A TEP FE analysis with solid elements model is carried out to predict the welding angular distortion, which is validated by comparing with experimental results. Then, inherent deformations in this examined fillet welded joint are evaluated as a loading for the subsequent elastic FE analysis. Also, the simultaneous welding to assemble this fillet welded joint is numerically considered and its inherent deformations are evaluated.(2) To predict the welding induced buckling in the production of ship panel structure, a shell element model of considered ship panel is then employed for elastic FE analysis, in which inherent deformation evaluated beforehand is applied and large deformation is considered. The computed results obviously show welding induced buckling in the considered ship panel structure after welding. With its instability and difficulty for straightening, welding induced buckling prefers to be avoided whenever it is possible.     

渗水作用下膨胀土中单桩承载变形特性研究

目前膨胀土中桩基设计仍基于非膨胀土力学的设计原则。基于FLAC3D采用热-力耦合方法实现吸热膨胀来模拟膨胀土的吸湿膨胀,并重点阐述温度场模拟湿度场的关键参数取值方法。建立膨胀土中单桩三维实体模型,得出渗水作用下膨胀土中单桩的荷载变形特性、桩侧摩阻发挥特征,并分析了桩长、桩径、膨胀系数等对单桩承载特性的影响规律。研究结论:非扩底桩最小桩长宜大于2倍膨胀影响深度;细长桩比短粗桩更能有效降低膨胀土中桩顶的位移。该方法可获得渗水作用下任一时刻的桩身受力变形特性,为研究膨胀土中桩基受荷性能提供一种可行的变通手段。     

高速铁路测量建立独立坐标系的数学模型

研究目的：在高速铁路线路测量中,由于线路长,常常跨越多个投影带,在统一坐标系中投影变形大,不能满足高速铁路测量精度的要求.针对这一问题,必须采取有效的约束条件和措施,使得长度变形小于1/40 000,从而满足铁路测量精度要求. 研究方法：本文从解决铁路测量坐标系中存在的长度变形出发,首先分析了高斯投影长度变形,然后提出了建立分段独立坐标系的方法,使其投影长度变形不大于1/40 000. 研究结果：文中给出了高速铁路测量建立独立坐标系的4种数学模型,有效的解决了在投影过程中长度变形问题. 研究结论：利用模型可以很好的解决投影变形对工程建设的影响,容易满足高速铁路测量精度要求,方便了工程施工测量,对高速铁路的建设有很好的实用性.若在铁路测量中应用,可极大地提高勘测精度,有着广阔的应用前景.     

Stochastic capacity expansion models for airport facilities

It is important and also challenging to plan airport facilities to meet future traffic needs in a rapidly changing environment, which is characterized by various uncertainties. One key issue in airport facility development is that facility performance functions (delay levels as functions of capacity utilization rates) are nonlinear, which complicates the solution method design. Potential demand fluctuations in a deregulated aviation market add another dimension to the decision making process. To solve this problem, a deterministic total cost minimization model is proposed and then extended into stochastic programs, by including uncertainties in traffic forecasts. After the exploration of properties of the delay cost function, an Outer-Approximation (OA) technique which is superior to the existing discrete approximation is designed. After model enhancements, an efficient solution framework based on the OA technique is used to solve the model to its global optimality by interactively generating upper and lower bounds to the objective. Computational tests demonstrate the validity of developed models and efficiency of proposed algorithms. The total cost is reduced by 18.8% with the stochastic program in the numerical example.