国道108线广元段公路桥梁裂缝病害及加固对策     

魏云杰  孙跃胜  许模 《中国地质灾害与防治学报》2005,16(2):129-131,153

国道108线广元段由于地质地貌条件复杂、重载作用及施工质量未能保证，桥梁裂缝病害较为普遍。文章简要介绍了沿线工程地质条件，按裂缝病害的成因将其分为3种类型：即桥台填土上部不密实引起的裂缝病害、桥台填土整体不密实引起的裂缝病害及地基土不均匀引起的裂缝病害。分别提出3种加固对策：即压浆、预应力对穿锚索锚梁及高压旋喷技术对上述病害进行治理。通过工程实例证明了这3种措施的有效性，为公路桥梁类似裂缝灾害提供了实践经验。这3种治理措施的优点为工艺简单、成本较低。但是桥梁病害的治理往往为隐蔽工程，施工难度较大、检测困难。对于压浆和高压旋喷加固工程，必须进行取芯检测，而预应力对穿锚索锚梁在施工过程中必须严格控制水平孔的倾斜度，保证施工质量。  相似文献   

Laboratory Studies Of Wind Stress Over Surface Waves   总被引：4，自引：0，他引：4  

B. Mete Uz  Mark A. Donelan  Tetsu Hara  Erik J. Bock 《Boundary-Layer Meteorology》2002,102(2):301-331

Simultaneous laboratory observations of wind speed, wind stress, and surfacewind-wave spectra are made under a variety of wind forcing patterns using cleanwater as well as water containing an artificial surfactant. Under typical experimentalconditions, more than half of the total stress is supported by the wave-induced stressrather than by the surface viscous stress. When the surfactant reduces the shortwind-wave spectra, the wind stress also decreases by as much as 20–30% at agiven wind speed. When the wind forcing is modulated in time, the wind stresstends to be higher under decreasing wind than under increasing wind at a givenwind speed, mainly because the response of short wind-wave spectra to varyingwind forcing is delayed in time. These examples clearly demonstrate that therelationship between the wind speed and the wind stress can be significantlymodified if the surface wave field is not in equilibrium with the wind forcing.Next, we examine whether the wind stress is estimated accurately if the wave-inducedstress by all surface wave components is explicitly evaluated by linear superpositionand is added to the surface viscous stress. It is assumed that the surface viscous stressis uniquely related to the wind speed, and that the wind input rate is determined by thelocal, reduced turbulent stress rather than the total stress. Our wind stress estimatesincluding the wave contributions agree well with observed wind stress values, evenif the surface wave field is away from its equilibrium with the wind in the presenceof surface films and/or under time-transient wind forcing. These observations stronglysuggest that the wind stress is accurately evaluated as a sum of the wave-induced stressand the surface viscous stress. At very high winds, our stress estimates tend to be lowerthan the observations. We suspect that this is because of the enhancement of wind stressover very steep (or breaking) short wind-waves.  相似文献   

滑坡治理中格构锚固结构的解析解分析   总被引：17，自引：0，他引：17  

许英姿  唐辉明 《地质科技情报》2002,21(3):89-93

在分析格构锚固结构受力的基础上 ,将格构梁简化为受集中力作用的弹性地基上的梁 ,提出了格构锚固结构的力学模型 ,利用 Winkler弹性地基上梁的解析解对格构梁进行了内力和变形的分析 ,发现格构梁的受力状况受弹性特征λ、梁格间距 ls以及悬臂长度影响 ;建议梁长 l与λ宜满足 lλ≥ 2π;采用较小间距的格构梁以及小吨位锚索 ,间距宜满足 lsλ<π/ 2 ,悬臂长度取 (0 .3～ 0 .5 ) ls,并将分析结论应用于三峡库区巴东太矶头东滑坡治理工程的设计中  相似文献   

锚杆动测问题的数值解     

许明  张永兴  李燕 《世界地震工程》2003,19(3):68-72

建立了锚杆动测问题的有限元模型，并对锚杆中的缺陷进行了数值模拟，获得了位移场的数值解。对该解在时域和频域范围内的讨论表明，锚杆中的缺陷将引起动测曲线一系列的变化，为现场动测曲线的识别提供了依据。  相似文献   

长效振弦式锚索测力计应用研究   总被引：1，自引：0，他引：1  

王清标  吕爱钟  邓铁六 《岩土力学》2003,(Z1)

介绍了长效振弦式锚索测力计传感器的工作原理、结构特点、技术性能和配套仪器,并对主要相关技术的应用研究成果作了论述:(1)弱激发电路解决频率不一致问题;(2)微小变形原则解决长期稳定性问题;(3)新数学模型提高了传感器准确度,二次仪表提高了传感器准确度。  相似文献   

兴山县龙王嘴边坡稳定性分析与加固设计     

傅旭东  邹勇  邵中勇 《岩土力学》2003,(Z2)

龙王嘴边坡系坡高达70 m、坡角达70 °的高陡岩质边坡。分析了宜-秭公路石峡段龙王嘴高边坡变形的地质条件,在定量评价龙王嘴高边坡稳定性的基础上,进行了该高边坡的施工图加固设计。根据其特点将350 m长的坡段分为A,B,C三个区,分别采取预应力锚索与锚杆加固、挂网喷射混凝土支护和喷射混凝土支护等措施,实践证明,工程治理效果良好。  相似文献   

Numerical Simulation of Drag Partition over Rough Surfaces     

An Li  Yaping Shao 《Boundary-Layer Meteorology》2003,108(3):317-342

We present a numerical simulation of drag partition over rough surfaces. A computational fluid dynamics model is applied with high resolution to simulatingturbulent flows over arrays of roughness elements positioned on asmooth surface. The skin drag on the surface and the pressure drag on the roughnesselements are computed. The simulated drag partition compares well with wind-tunnelmeasurements and theoretical estimates for similar rough surfaces. This confirms that the computational approach offers an alternative to wind-tunnel and field experiments in studying drag and drag partition. The model is then applied to studying drag partition over rough surfaces with various roughness configurations. It is shown that drag partition depends not only on the magnitude of the roughness frontal area but also on the sizes and arrangement of roughness elements, because (1) the pressure drag coefficient is sensitive to roughness-element dimensions and (2) the arragement of roughness elements lead to different interferences of turbulent wakes. The impact ofthe latter factor is not insignificant.  相似文献   

端头扩大型土层锚杆技术   总被引：7，自引：0，他引：7  

夏柏如  王贵和 《地质与勘探》1997,33(3):53-55

锚固力是土锚重要的工作性指标，端头扩大型土层锚杆技术作为提高锚固力的一种有效手段虎来越得到人们的重视，为此，在这着重介绍国内外土层锚杆端头扩大技术的原理及应用发展情况。  相似文献   

大跨度切眼锚网锚索支护研究   总被引：5，自引：0，他引：5  

吴添泉 《岩土力学》2004,25(Z1):141-143

全煤大跨度切眼传统的支护方式是钢棚支护,为解决无轨胶轮车直接进入工作面,提高工作面设备安装效率,课题组进行锚网锚索支护试验与研究。该项目的试验成功,为矿井高产高效创造了条件。  相似文献   

长沙现代大厦复合土钉墙基坑支护方案设计          下载免费PDF全文

高林渊  张喜文 《探矿工程》2004,31(8):15-18,22

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。  相似文献