长沙现代大厦复合土钉墙基坑支护方案设计

分析了长沙现代大厦基坑的岩土工程条件及周边环境条件，在此基础上对几种基坑支护方案进行了分析论证，并对所采用的复合土钉墙支护方案进行了设计计算。     

东营市矿产资源开发利用现状与保护措施

以东营市矿产资源总体规划为指导,进行矿产资源开发利用与保护措施研究,在开发利用现状的基础上分析当前存在的矿产资源后备基地紧缺、综合利用水平不高以及过度开采等问题,进而提出促进矿产资源开发利用与保护的措施,以便更好地为东营市经济建设和社会发展服务。     

昌邑市生态地质环境保护对策

昌邑市位于山东省北部莱州湾南岸,南北狭长,南部为丘陵,中部和北部为平原,潍河纵贯南北。在查明市域内各种生态环境地质问题的基础上,将昌邑市划分为4个生态地质环境保护区和1个生态地质环境保护带,针对各区存在的主要问题,提出了不同的保护对策。     

西准噶尔包古图Ⅴ号岩体围岩蚀变的特征及ETM+蚀变信息的提取

以新疆西准噶尔包古图Ⅴ号岩体为例,系统论述了包古图Ⅴ号含矿岩体的围岩蚀变分带和蚀变期次。结合ETM+数据的特征,选择多种遥感图像预处理方法组合,建立了基于典型蚀变矿物的特征光谱拟合技术的多光谱遥感蚀变信息提取模型,即遥感数据的归一化处理(Calibration )+掩膜(Mask)+混合像元分解(Endmember Unmixing)+波谱拟合(Spectral Feature Fitting)+ SAM+分类(分割)的CES模型。据此模型对岩体进行信息提取,并与化探资料叠加验证了该方法的可行性,取得了较满意的效果。     

自嵌式景观加筋挡土墙的特点及工程应用

自嵌式景观挡土墙具有施工工艺简单、稳定性好、造价低、美观、环保等特点。针对自嵌式景观挡土墙施工中的关键技术问题进行探讨,提出了相应的技术措施。     

海底双层管单层连接管道结构受力分析

粘性高的海洋石油通常需要通过海底保温管道加温输送.温度变化会引起管道变形,并在管壁内产生较大的温度应力.同时,管道正常运营期间还受到管道内压、外压、管内流体粘滞力和土体摩擦力等环境荷载的作用.复杂的环境可能导致海底管道轴向应力过大发生破坏.为了提高铺管效率,提出了双层管单层连接管道这一特殊管道形式,并从理论上分析温度变化和环境荷载对该管道的影响,计算正常运行时管道不同位置处横截面内最大Von-Mises应力.最后得到了Von-Mises应力沿管道轴线分布情况,发现内管和单层连接管的应力一般比外管大,变径管和内管的焊缝处是Von-Mises应力最大的地方.     

Reduction of sand demand for shore protection

Beach nourishment is an environmentally preferred method of shore protection, but the annual sand requirement may lead to substantial maintenance costs. The shoreline processes, involving the surf zone, beach and dune, are reviewed with the aim of reducing the annual sand requirement of eroding shorelines. It is shown that surf zones with equilibrium profiles, on which the wave energy conversion is evenly distributed across the surf zone, from experience for given conditions indicate least loss of sand. On steep, eroding shorelines it may be difficult to establish an equilibrium profile. For such cases, the use of perched surf zones is recommended, which are supported at the seaward limit by an underwater sill. For reduction of littoral transport, the use of pervious pile groynes is recommended. These are arguably more efficient than impervious groynes. The sand loss from a usually dry beach by raised water levels is shown to be a function of the beach slope and is least when the storm waves at raised water levels do not cut an erosion escarpment. The loss of sand from a dune by infrequent severe storm tides can be prevented with the aid of a built-in membrane. These sand losses are usually large and constitute an uneconomic use of this sand resource. The proposed concepts and measures are linked to existing knowledge, augmented by data from the large wave flume (LWF) in Germany and field data from the North and Baltic Sea coasts.     

半潜平台浮子式系泊系统参数优化研究

通过在系泊缆中设置浮子可以改善系泊系统性能,降低平台运动响应。建立浮子式系泊系统的数值计算模型,验证浮子式系泊系统数值计算方法,详细分析浮子设计参数(设置位置和净浮力大小)变化对系泊缆张力特性与平台运动的影响规律,并根据得到的规律选择了优化的浮子系泊系统方案。最后对优化方案进行评估,表明优化方案可以显著降低系泊中的平台水平运动,尤其是低频运动,同时系泊缆张力变化不大,仍满足安全要求。研究结果可为今后浮子式系泊系统设计提供参考。     

Dynamic response and optimal design of structures with large mass ratio TMD

This paper investigates the dynamic behavior and the seismic effectiveness of a non‐conventional Tuned Mass Damper (TMD) with large mass ratio. Compared with conventional TMD, the device mass is increased up to be comparable with the mass of the structure to be protected, aiming at a better control performance. In order to avoid the introduction of an excessive additional weight, masses already present on the structure are converted into tuned masses, retaining structural or architectural functions beyond the mere control function. A reduced order model is introduced for design purposes and the optimal design of a large mass ratio TMD for seismic applications is then formulated. The design method is specifically developed to implement High‐Damping Rubber Bearings (HDRB) to connect the device mass to the main structure, taking advantage of combining stiffness and noticeable damping characteristics. Ground acceleration is modeled as a Gaussian random process with white noise power spectral density. A numerical searching technique is used to obtain the optimal design parameter, the frequency ratio alpha, which minimizes the root‐mean‐square displacement response of the main structure. The study finally comprises shaking table tests on a 1:5 scale model under a wide selection of accelerograms, both artificial and natural, to assess the seismic effectiveness of the proposed large mass ratio TMD. Copyright © 2011 John Wiley & Sons, Ltd.     

Seismic response of steel frame structures with hybrid passive control systems

The concept of the hybrid passive control system is studied analytically by investigating the seismic response of steel frame structures. Hybrid control systems consist of two different passive elements combined into a single device or system. The hybrid systems investigated in this research consist of a rate‐dependent damping device paired with a rate‐independent energy dissipation element. The innovative configurations exploit individual element strengths and offset their weaknesses through multiphased behavior. A nine‐story, five‐bay steel moment‐frame was used for the analysis. Six different seismic resisting systems were analyzed and compared. The conventional systems included a special moment‐resisting frame (SMRF) and a dual SMRF–buckling‐restrained brace (BRB) system. The final four configurations are hybrid passive systems. The different hybrid configurations utilize a BRB and either a high‐damping rubber damper or viscous fluid damper. The analyses were run in the form of an incremental dynamic analysis. Several damage measures were calculated, including maximum roof drift, base shear, and total roof acceleration. The results demonstrate the capability of hybrid passive control systems to improve structural response compared with conventional lateral systems and to be effective for performance‐based seismic design. Each hybrid configuration improved some aspect of structural response with some providing benefits for multiple damage measures. The multiphased nature provides improved response for frequent and severe seismic events. Copyright © 2011 John Wiley & Sons, Ltd.