Elastic waves at a corrugated interface between two dissimilar fibre‐reinforced elastic half‐spaces

The reflection and transmission phenomena of elastic waves incident at a corrugated interface between two dissimilar fibre‐reinforced elastic half‐spaces have been analysed. Using Rayleigh method of approximation, the expressions of the reflection and transmission coefficients are obtained in closed form for the plane interface as well as for the first order approximation of the periodic interface ζ = d cos px. All these reflection and transmission coefficients of regular and irregular waves are found to be the functions of angle of incidence and elastic parameters of the media. Moreover, the coefficients of irregularly reflected and transmitted waves are found to be proportional to the amplitude of the corrugated interface and are functions of the frequency of the incident wave. Numerical computations have been performed for a specific model to compute these coefficients and results obtained are shown graphically. The results of Singh and Singh (Sadhana 2004; 29 :249–257) and Ben‐Menahem and Singh (Seismic Waves and Sources. Springer: New York) have been derived from our analysis as particular cases. Copyright © 2006 John Wiley & Sons, Ltd.     

Cyclic tests on large‐scale models of existing bridge piers with rectangular hollow cross‐section

Cyclic tests on two large‐scale models of existing bridge piers with rectangular hollow cross‐section were performed in the ELSA laboratory. The prototype structure is an existing reinforced concrete highway bridge constructed in Austria in 1975. The piers presented several seismic deficiencies and consequently they showed poor hysteretic behaviour and limited deformation capacity as well as undesirable failure modes that do not comply with the requirements of modern codes for seismic‐resistant structures. Experimental data are compared to numerical and empirical predictions. Copyright © 2003 John Wiley & Sons, Ltd.     

高压喷射注浆技术在白龟山水库顺河坝防渗墙围井试验中的应用

本次围井高喷试验,选用三重管摆喷法处理方案,施工采用两序施工方法.砼墙体连续均匀,孔与孔之间连接较好,其防渗、强度、厚度均能满足设计要求.     

纤维水镁石在氨基酸水溶液中的电化学及溶解作用研究

在模拟人体温度３７℃条件下,进行水镁石纤维粉尘与氨基酸作用的实验研究,测定在７２ｈ内溶液过程中ｐＨ值的电导率的变化,结果表明,纤维矿物在氨基酸中发生了有机配合作用,并且中性氨基酸对矿物的溶解能力最强。     

罗丹宁纤维富集分离－示波极谱法测定地质样品中的金

考察了螯合罗丹宁纤维富集分离。示波极谱法测定Ａｕ的条件，选用０．１５ｇ罗丹宁纤维装柱（Φ５ｍｍ×８０ｍｍ）富集Ａｕ，吸附Ａｕ后的罗丹宁纤维于７００℃灰化的烧，浸取物在ＮａＯＨ底液中用示波极谱法测定。测定范围为０．４～１４０μｇ／ｍｌＡｕ，经对标样分析，结果与标准值相符。对Ａｕ含量为４．９３×１０￣－６级的标样进行１０次测定，方法精密度（ＲＳＤ）为１．１４％。方法选择性高、稳定性好，适用于Ａｕ含量在０。２×ｌ０￣－６以上地质样品的分析。     

喷锚支护节理岩体的弹性复合单元模型

利用复合单元技术,建立节理岩体喷锚支护的弹性模型。该模型可先不考虑节理、锚杆、喷层等细部结构,生成常规有限元网格,然后根据节理、锚杆、喷层的相关信息,形成复合单元网格信息。该模型可重点考虑锚杆和喷层在节理面上的局部化非线性变形与相互作用关系。算例研究验证了模型的合理性。该复合单元算法同时包含等效模拟和离散模拟的优点,有着较好的应用前景     

喷混凝土边坡温度场与应力场耦合的有限元时效分析

由于混凝土材料与岩土材料的热传导系数、比热容与热膨胀系数的差异,在温度的循环变化下使得喷射混凝土边坡容易于喷层与岩土层的结合面处产生应力集中而开裂。采用有限元的方法,考虑地应力与温度应力的耦合作用,分析了在一定的边界温度作用下不同时刻边坡喷层面的水平位移,以及喷层与岩层结合面处的剪应力的分布规律;指出在温度应力与地应力的共同作用下,喷混凝土边坡坡顶与坡脚均为容易发生破坏的地方,通常坡顶的破坏型式为拉张破坏而坡脚则为剪切破坏;边坡内的温度分布、边坡表面的位移与应力的变化均存在一定的时间效应,这一规律与实测规律比较吻合。分析结果表明,当温度变化剧烈时边坡的防护必须考虑温度应力的影响。     

软岩井巷喷射混凝土抗渗机制及模拟试验研究

针对豫西滑动构造区软岩巷道在喷射混凝土支护条件下的抗渗性能问题,从立方定律基本理论着手,结合地下水层流渗透特点,按照不同的施工条件进行了黏结面渗透性能的模拟试验,并导出了相应的计算公式。通过试验结果的对比和分析,可以清晰了解到岩性、粗糙度、界面剂和大型刻槽等各种影响因素之间相互作用的过程和机理。即：（1）黏结面作为结构上的薄弱面,其渗透性要远远大于岩体和混凝土本体的渗透性,而粗颗粒软岩黏结面的渗透性也要远远大于相应的细颗粒软岩;（2）限制岩体结构面的粗糙度、使用各种界面剂以及布置适当的人工刻槽均能提高黏结面的抗渗性能;（3）岩体结构的荷载条件是黏结面渗透性能的一个重要影响因素。     

喷锚支护结构在膨胀土地区基坑支护中的应用

膨胀土地区的基坑支护一般采用土钉墙型式,但出现了较多的垮塌事故。详细介绍了邯郸市某小区综合楼的膨胀土基坑喷锚支护工程的设计与施工方法。考虑膨胀土吸水膨胀失水收缩对边坡稳定性的影响,针对基坑支护结构验算的相关参数,依据膨胀土地区情况给予了相应的调整。基坑分层开挖进行喷锚支护后整体稳定性较好,达到了预期目的。本实例旨在为膨胀土地区基坑支护设计与施工提供一个借鉴和参考。     

Coherent beam combining of hybrid phase control in master oscillator-power amplifier configuration

A novel scalable architecture for coherent beam combining with hybrid phase control involving passive phasing and active phasing in master oscillator-power amplifier configuration is presented. Wide-linewidth mutually injected passive phasing fibre laser arrays serve as master oscillators for the power amplifiers, and the active phasing using stochastic parallel gradient descent algorithm is induced. Wide-linewidth seed laser can suppress the stimulated Brillouin scattering effectively and improve the output power of the fibre laser amplifier, while hybrid phase control provides a robust way for in-phase mode coherent beam combining simultaneously. Experiment is performed by active phasing fibre laser amplifiers with passive phasing fibre ring laser array seed lasers. Power encircled in the main-lobe increases1.57 times and long-exposure fringe contrast is obtained to be 78% when the system evolves from passive phasing to hybrid phasing.