Seismic performance and design of bridge column-to-pile shaft pipe-pin connections in precast and cast-in-place bridges

Hinge or “pin” connections may be used in integral bridges to connect columns to pile shafts to reduce the foundation force demand. Used in combination with prefabricated columns, pins facilitate accelerated bridge construction (ABC). These innovative methods could improve the quality and economy of project compared with conventional construction in seismic regions. This study developed pipe pins that reduce moment transfer between the column and pile shaft under seismic excitations. The pipe pins consist of two steel pipes and a rod that transfer shear and tension while allowing rotation between the column and shaft. The primary objective of this research was to investigate the seismic performance and develop design guidelines of column-to-pile shaft pipe pins for cast-in-place and precast constructions. This research was composed of experimental and analytical studies. The experimental portion of the study consisted of testing of a large-scale bent model subjected to seismic loadings. The test results confirmed that the proposed design method meets the safety and performance requirements of the codes under seismic loadings. The pins maintained structural integrity with minimal damage, while the columns reached the full plastic hinge capacity. The analytical studies consisted of (a) a simple stick model to be used as a design tool, (b) a finite element model (FEM) for global analysis of bridges, and (c) an elaborate FEM to investigate the microscopic performance and interaction of the components. The analytical models were subsequently used in parametric studies.     

煤层气掏穴井钻探施工技术

通过工程实例，介绍了煤层气掏穴井施工的目的、技术要求、设备机具、施工工艺，以及掏穴作业和技术措施。     

煤矿立井井筒非采动破裂的人工神经网络预测

应用人工神经网络的基本原理,建立了一个基于神经网络的煤矿立井井筒非采动破裂的预测系统,实现了立井井筒破裂预测的智能化。最后将神经网络预测结果与数值计算结果对比,认为应用人工神经网络对立井井筒破裂时间的预测比较准确、实用。     

电法探测井筒含水体的试验研究

结合工程实例 ,介绍运用电法探测井筒含水体的方法特点。在井筒掘进中配合电法探测含水体 ,可以减少钻探工程量 ,缩短工期 ,因而对井筒掘进有一定的指导意义     

疏水沉降地层竖向可缩性井壁附加力分布规律研究

通过数值分析和模型试验研究,揭示了竖向可缩性井壁附加力分布规律。研究表明,可缩性井壁可有效衰减附加力和井壁截面轴向应力;与单一可缩接头相比,设置两个可缩接头衰减附加力更为有效;提出的可缩接头设置优化原则,对科学、合理地设计竖向可缩性井壁具有重要的指导意义。     

强含水层的浆液低压运移及其井筒堵水应用

采用液体溶质水动力弥散方程及其相应分析方法描述治理破裂井筒注浆的浆液运移过程,通过坐标变换推导出径向水流条件下考虑吸附作用的浆液浓度解析公式。同时,结合一个煤矿风井堵水工程实例,介绍了如何根据现场观测资料,采用标准曲线法分析流动浆液吸附性参数和指导注浆进程的应用过程。      

煤矿井筒重复破坏的化学注浆治理

兴隆庄矿西风井井筒事隔5a后第二次发生破坏,原因是松散层失水造成第四系压缩下沉。经分析论证,采用地面注水泥浆-化学浆复合注浆工艺,通过浆液在裂隙中流动、凝胶、劈裂、充填,可实现对岩体裂隙的封堵,达到控水、增强、防止沉降的目的。      

贯通测量误差来源及质量控制技术探讨

贯通测量是矿山测量的的一项重要工作。贯通工程质量的好坏,直接关系到整个矿井的建设、生产和经济效益。本文从地面控制网误差、陀螺定向、导入高程、井下控制网误差四个大的方面对贯通测量的误差来源进行了分析,并从贯通测量的各个环节对质量控制技术进行了详细的探讨。     

上海天文台25m天线驱动系统的探讨

对中国科学院上海天文台 2 5m天线的驱动结构进行了分析。并对该天线的方位速度及使用更多电机同时驱动天线方面的问题进行了探讨     

厚表土深立井基岩段探水预注浆施工技术

山东单县煤田陈蛮庄煤矿松散层厚度为527.5m,预注浆段井深为750.-758.40m,预计涌水量为26m^3/h,为有效治理工作面水害,确保井筒的安全施工和进度质量,根据基岩段围岩条件及水文地质条件设计了10个预注浆孔,注浆段混凝土材料由C40变为C70,确定含水层预注浆的止浆垫厚度为10m,预留岩帽厚度为4.5m。在注浆时采取高压分段注浆的方法,结果使主井涌水量减少到2.4m^3/h,效果显著。通过此次注浆,总结出了＂探、注、堵＂等一套深立井基岩含水层综合注浆堵水施工技术,对深立井井筒工作面探水预注浆和安全施工具有借鉴意义。