大断面地铁车站隧道软弱围岩渐进破坏规律模型试验研究

以贵阳市地铁2号线阳明祠车站为背景,采用室内模型试验模拟大断面地铁车站施工过程中隧道塌方破坏过程,明确施工期间大断面隧道塌方破坏过程机制,对比分析围岩和路面的变形。结果表明:通过围岩重力作用模拟隧道施工过程中塌方过程,与实际塌方过程基本吻合,弥补了常规加载破坏的不足;围岩渐进破坏过程表现为裂隙出现-裂隙发展-裂隙贯通-围岩塌方,支护渐进破坏过程表现为变形缓慢增加-变形快速增加-裂缝快速发展-支护破坏;围岩渐进破坏与支护渐进破坏相互作用,共同发展;在实际施工过程中,当支护变形大幅增加时,应增加支护强度,同时还应及时注浆、打设长锚杆,以减缓围岩裂隙发展,阻断围岩渐进破坏过程。     

Simulation on progressive collapse behaviour of whole ship model under extreme waves using idealized structural unit method

To ensure the safety of navigating ship, working loads and structural load-carrying capacity are two important aspects. In the present paper, a total simulation system combing load calculation and structural collapse analysis is applied to simulate progressive collapse behaviour of a single-hull Kamsarmax type bulk carrier. A three dimensional singularity distribution method is adopted to calculate pressure distribution with time history. A mixed structural model, collapse part simulated by ISUM elements and remaining part by elastic FEM elements with relative coarse mesh, is proposed for collapse analysis. Progressive collapse behaviour obtained by ISUM is good agreement with that by nonlinear software package, MARC. However, the calculation time of ISUM analysis is about 1/70 of MARC analysis. The applicability to structure system, high accuracy and sufficient efficiency of ISUM had been demonstrated.     

渐变刚度钢板弹簧的设计计算

本文探讨了渐变刚度钢板弹簧的变形规律，并导出这种结构型式钢板弹簧的载荷，变形，应力的设计计算公式。     

旧水泥砼路面加铺级配碎石补强层施工工艺探讨

如何有效防治旧水泥混凝土路面上加铺沥青面层产生反射裂缝,是路面修复工程中所面临的一个较普遍问题。文章以国道324线田阳段利用级配碎石作为补强层成功处理该问题为实例,探索了旧水泥砼路面加铺级配碎石补强层的设计与施工方法。     

沥青混凝土搅拌设备标准理论试验工况的研究

沥青混凝土搅拌设备的工作条件、工作对象等工况参数是一个经常变化的量，直接影响设备的性能指标，因此需用标准定义下的工况参数予以修正。文章主要介绍了标准级配配比、沥青标号、冷集料含水量及初始温度、出料温度、大气状况等标准理论试验工况的确定。     

级配碎石基层材料组成设计与工艺控制的研究

在我国，级配碎石作为沥青路面的基层，目前尚处于试验研究阶段。要提高级配碎石基层的强度、均匀性，以确保在常规沥青层厚度下减缓反射裂缝、排水等功能的正常发挥，除做好材料选择、级配设计及结构层组合外，关键在工艺控制。     

Progressive collapse analysis of ship hull girders subjected to extreme cyclic bending

This paper introduces a novel analytical method to predict the buckling collapse behaviour of a ship hull girder subjected to several cycles of extreme load. This follows the general principles of the established simplified progressive collapse method with an extended capability to re-formulate the load-shortening curve of structural components to account for cyclic degradation. The method provides a framework for assessing residual hull girder strength following a complex series of unusually extreme load events where the wave induced bending moment rises close to, or even surpasses, the monotonic ultimate strength. These load events may be sequential, such as might be caused by a series of storm waves, or they may occur as a collection of discrete events occurring over a longer period. The extreme cyclic bending amplifies the distortion and residual stress initially induced by fabrication in the flanges of the girder, which results in a deterioration of the residual ultimate strength. Validation is firstly completed through a comparison with previously published experimental work and secondly via comparison with numerical simulation on four ship-type box girders using the nonlinear finite element method.     

水泥稳定沙砾的逐级填充设计及应用

采用逐级填充对水泥稳定砂砾级配进行设计并进行强度试验,最后铺筑试验路进行验证。研究结果表明,采用逐级填充设计的水泥稳定砂砾比起传统级配的混合料降低水泥剂量0.6%,现场试验表明逐级填充设计的混合料能满足设计要求。     

Ultimate strength of container ships subjected to combined hogging moment and bottom local loads,Part 2: An extension of Smith's method

This paper is the second of two companion papers concerning the ultimate hull girder strength of container ships subjected to combined hogging moment and bottom local loads. The nonlinear finite element analysis in Part 1 has shown that local bending deformation of a double bottom due to bottom lateral loads significantly decreases the ultimate hogging strength of container ships. In this Part 2, extending Smith's method for pure bending collapse analysis of a ship's hull girder, a simplified method of progressive collapse analysis of ultimate hogging strength of container ships considering bottom local loads is developed. The double bottom is idealized as a plane grillage and the rest part of the cross section as a prismatic beam. An average stress-average strain relationship of plate/stiffened plate elements employed in Smith's method is transformed into an average stress-average plastic strain relationship, and implemented in the conventional beam finite element as a pseudo strain hardening/softening behaviors. The extended Smith's method is validated through a comparison with nonlinear finite element analysis.     

级配碎石垫层施工中的控制要点

垫层作为路面结构的组成部分,日益显现出其重要作用,它是路面和路基的连接纽带,其施工质量的控制尤为重要,因其直接影响工程质量的好坏。文章对垫层施工中原材料及施工过程中质量控制的关键要点进行了阐述,以其加强对垫层的质量控制,充分发挥其在路面结构层中的重要作用。