免拆保温墙模复合剪力墙体系模板设计

提出一种新型保温墙模--玻化微珠保温板,墙模施工后不必拆除,与内部混凝土共同形成复合剪力墙体系,可以实现结构施工过程中完成外墙保温施工.根据墙体施工要求及模板受力特点进行模板设计,确定了适用于不同情况的模板规格.在此基础上,采用合理的计算模型和简化方法,选用适用的荷载值对其进行受力分析,计算了其所受最大混凝土侧压力,模板的强度、刚度,并对其不同荷载作用下的值进行比较,计算结果表明所设计模板强度高,抵抗变形能力强,保温墙模用于墙体施工具有技术可行性及经济合理性.     

支护结构侧压力计算方法研究

针对选用水土合算方法与水土分算方法及采用不同指标对水土侧压力计算结果的影响．在理论分析基础上结合工程原型观测数据对其进行了讨论．     

地震作用下沿高变刚度框剪结构的计算方法

本文在对框剪结构连续化处理的基础上，在框剪结构刚度变化区间进行离散化，推导出框－剪单元在考虑刚度变化和剪切变形影响时的内力，位移关系式，给出了沿高变刚度框剪的结构地震反应计算方法。本文给出了算例，说明考虑沿高变刚度对框剪结构内力及位移的影响是必要的。     

大粒径碎石桩加固超软弱土河道边坡的现场试验

本文介绍了用大粒径碎石桩加固不排水强度低于20 kPa的超软弱河道边坡的施工方法，碎石桩单桩和复合地基的检测内容和检测方法。提供了由测试数据获得的抗剪强度指标与面积置换率的关系、充盈系数与密实电流和留振时间的关系。用实测碎石桩复合地基抗剪强度计算了施工期边坡稳定安全系数，其结果满足规范要求。工程实例表明大粒径碎石桩加固人工河堤淤泥土层是成功的。     

Seismic behaviour of coupling beams in a hybrid coupled shear walls

Steel coupling beams in a hybrid coupled shear wall provide a viable alternative for concrete coupling beams coupling individual reinforced concrete wall piers. Due to the lack of information, current design methods for calculating embedment lengths are silent about cases in which hybrid coupled walls have connection details of stud bolts and horizontal ties. In this work, an analytical study was carried out to develop a model for calculating the embedment lengths of embedded steel sections. Five models for calculating embedment lengths in a hybrid coupled wall are developed as variations of the Prestressed Concrete Institute guidelines for steel brackets attached to reinforced concrete columns. In addition, experimental studies on the hybrid coupled shear wall were carried out. The main test variables were the ratios of the coupling beam strength to the connection strength. The test results indicate that it is more advantageous to design the coupling beams as shear yielding members since the shear-critical coupling beam exhibits a more desirable mode of energy dissipation than the flexure-critical coupling beam.     

Influence of stress condition on adiabatic shear localization of tungsten heavy alloys

Dynamic deformation and failure behavior of a tungsten heavy alloy (93W) under complex stress condition are studied using a split Hopkinson pressure bar (SHPB) apparatus. Cylindrical, step-cylindrical and truncated-conic specimens are used to generate different stress condition in an attempt to induce strain localization in the alloy. The microstructure of the specimens after tests is examined by optical microscopy and scanning electronic microscopy (SEM). It is found that in all the specimens, except the cylindrical ones, intense strain localization in the form of shear bands is initiated at stress concentration sites. In order to analyze the stress condition of different specimen geometry, finite element simulations are also presented. The Johnson-Cook model is employed to simulate the thermo-viscoplastic response of the material. It is found that dynamic deformation and failure modes are strongly dependent on the geometry of the specimens. The stress condition controlled by specimen geometry has significant influence on the tendency for shear band formation. The adiabatic shear band has general trends to initiate and propagate along the direction of maximum shear stress. It is suggested that further studies on the control of the stress condition to promote shear band formation be conducted in order to improve the penetration performance of the tungsten heavy alloy.     

HRD弱凝胶钻开液的研究与应用

HRD弱凝胶钻开液是一种新型无粘土相水平井钻开液，它所形成的弱凝胶具有独特的流变性，表观粘度低、动塑比高、低剪粘度高、静切力恢复迅速、无时间依赖性，具有很好的动态携砂和静态悬砂能力，能有效地克服水平井或大斜度井段携砂难、易形成岩屑床等问题。同时该体系在低剪切状态下具有高粘弹特性，可减少钻开液中固相和液相对储层的损害，有利于储层保护。在冀东油田水平井应用时，井壁稳定、可有效抑制岩屑床的形成，井眼畅通保证了钻井和完井作业的顺利进行。     

A dynamic oscillatory test that fulfills the objective of the elastic recovery test for asphalt binders

The ductilometer is currently being used by the asphalt pavement community for determination of elastic recovery of asphalt materials. Briquet specimens are pulled apart at 5 cm/min, held after a specified elongation, then severed at the center and allowed to recover undisturbed for 1 h with the idea of getting a measure of the ability of the asphalt material to recover after imposing a deformation. Materials with poor ability to recover are known to lend themselves to permanent deformation resulting in rutting of pavements. The Superpave specification parameter |G*|/sinδ recommended by the Strategic Highway Research Program was found not to relate well with observed rutting of mixtures that used polymer-modified asphalts with increased elastic behavior. This led researchers to seek methods to refine this parameter. While refinement efforts have been ongoing, there has been an inclination on the part of a number of State Departments of Transportation to use the elastic recovery test to complement the Superpave specification tests. However, the elastic recovery test is truly not very elegant and accurate, and often fails to discriminate between the behaviors of differently modified binders. The present work suggests a dynamic oscillatory test using the dynamic shear rheometer DSR that would fulfill the objectives of the elastic recovery test. The elastic recovery term and the condition under which it is determined from DSR data are selected by observation of master plots of a wide variety of asphalt binders. The criterion is developed by observing the ability of the selected term in best discriminating asphalt binders for their elastic recovery behavior. It is recommended that the term cosδ determined at a temperature T = 82°C and frequency ω = 1 radian/s be used to assess the elastic recovery of asphalt materials. Cosδ (T = 82°C, ω = 1) > 0.04 is recommended as the criterion for acceptance of required elastic recovery behavior. The opinions, findings, and conclusions expressed in this document are those of the author only and not necessarily of the Federal Highway Administration or any other researcher at the Turner-Fairbank Highway Research Center.     

Interfacial damage in fibre‐reinforced composites subjected to tension fatigue loading

ABSTRACT The interfacial behaviour of fibre‐reinforced composites subjected to tension fatigue loading is studied based on the shear‐lag model. The governing equations of this problem are obtained and solved. In order to describe the interfacial debonding, the Paris fatigue crack growth formula as well as a modified degradation model for the coefficient of friction is adopted. Finally some important values related to interfacial debonding are obtained. In the present investigation, Poisson's contraction is considered.     

齿形节理渐进破坏直剪试验研究

通过对由两个齿形凸体组合构成的双齿节理进行直剪试验,分析了两个齿形凸体的起伏角相等时和不等时双齿节理的剪切特性;观察和分析含两种不同起伏角凸起体的双齿节理的渐进破坏过程与机理,以及两个齿形凸起体的排列顺序对此类双齿节理的剪切强度和变形特性的影响.