全长粘结型锚杆锚固性能研究     

毛筱霏  刘玉茜  赵冬 《世界地震工程》2011,27(4)

利用全长粘结型锚杆的Mindlin解,对锚固体的应力分布及抗拔力进行了理论分析,导出了抗拔承载力计算式,并结合新疆高昌故城土建筑遗址保护工程,就影响锚固体应力分布及锚固力的因素进行了探讨.结果表明,锚固体应力不能均匀地分布在锚固长度上,随着荷载的增加,应力分布区域变化不大;锚固长度存在临界值,超过该值时增加锚固长度对锚固力的影响甚微;锚杆直径越粗,锚固体上的剪应力分布越均匀,但工程选用时应结合岩土体特性.研究结果可为全长粘结型锚杆加固小型土体的设计理论和施工应用提供一定的数据储备和理论支持.  相似文献   

钢框架扩翼型节点抗震性能研究     

毛辉  王燕 《世界地震工程》2011,27(4)

基于4个梁端翼缘扩大型节点试件和1个传统节点试件的低周循环加载试验,对直接圆弧扩翼型节点和加侧板扩翼型节点2种钢框架扩翼型节点采用ANSYS软件进行了往复荷载作用下的节点性能有限元分析,研究了这2种不同型式的梁端扩翼节点的破坏形态、荷载-位移滞回曲线、骨架曲线、极限荷载、延性和耗能系数等抗震性能,其结果与试验结果吻合较好.研究结果表明,通过合理地设计扩翼截面,圆弧扩翼型节点和侧板扩翼型节点均能有效的将塑性铰移出焊缝热影响区,且较传统节点具有更强的承载力、延性和耗能能力,能满足我国现行抗震规范的要求.另外,圆弧扩翼型节点构造相对简单,扩翼处连接焊缝少,可避免焊接热影响区母材变脆而发生脆性撕裂,其抗震性能要优于梁端翼缘侧板加强型节点.  相似文献   

Pyrrhotite Re–Os and SHRIMP zircon U–Pb dating of the Hongqiling Ni–Cu sulfide deposits in Northeast China     

Linsu Lü  Jingwen Mao  Hongbo Li  Franco Pirajno  Zuoheng Zhang  Zhenhua Zhou 《Ore Geology Reviews》2011,43(1):106-119

The Hongqiling (HQL) magmatic Ni–Cu sulfide deposits (Jilin Province, NE China) are located at the southern margin of the eastern Xing'an–Mongolian Orogenic Belt (XMOB) of the eastern Central Asian orogenic belt (CAOB), situated between the Siberian Craton (SC) and the North China Craton (NCC). The HQL ore-bearing mafic–ultramafic intrusions intrude into the metamorphic rocks of the lowermost Huangyingtun Formation of the Hulan Group (HLG), whose lithology is herein identified as a hornblende–zoisite gneiss. SHRIMP zircon U–Pb dating for the HLG, country rock of the HQL deposits, indicated a maximum deposition age of 272.2 ± 4.3 Ma (95% confidence level, MSWD = 2.6, n = 14).Six pyrrhotite samples separated from massive Ni–Cu sulfide ores of the Fujia (No. 7) deposit yielded a Re–Os isotopic isochron age of 208 ± 21 Ma (95% confidence level, MSWD = 2.4, n = 6), indicating that the ore-formation age was Late Triassic. Re–Os isotope analyses showed an initial ¹⁸⁷Os/¹⁸⁸Os ratio of 0.315 ± 0.050. The γ_Os values ranged from + 137 to + 161 with an average of + 151, indicating that its ore-forming materials were mainly derived from mantle with possibly < 30% crustal Os contamination. Large scale magmatic Ni–Cu mineralization in eastern Jilin occurred in post-collisional tectonic setting in the Late Triassic.Our new results suggest that the ages of the Ni–Cu sulfide deposits in the CAOB within China tended to become younger from west to east, as manifested by the Late Caledonian (~ 440 Ma), through the Late Hercynian (300–265 Ma) to the Late Indosinian (225–200 Ma). Such variation could reflect the gradual closure and post-collisional orogeny between the SC and the NCC from west to east.  相似文献   

A tectono-genetic model for porphyry–skarn–stratabound Cu–Au–Mo–Fe and magnetite–apatite deposits along the Middle–Lower Yangtze River Valley, Eastern China     

Jingwen Mao  Guiqing Xie  Chao Duan  Franco Pirajno  Dazio Ishiyama  Yuchuan Chen 《Ore Geology Reviews》2011,43(1):294-314

The Middle–Lower Yangtze River Valley metallogenic belt (YRB), situated along the northern margin of the Yangtze craton, is characterized by porphyry–skarn–stratabound Cu–Au–Mo–Fe deposits in the areas of uplift and magnetite–apatite deposits in Cretaceous fault basins. Following detailed field investigations and a review of published data, we recognize two episodes of magmatism and mineralization in the YRB: 1) 156–137 Ma high-K calc-alkaline granitoids associated with 148–135 Ma porphyry–skarn–stratabound Cu–Au–Mo–Fe deposits and 2) 135–123 Ma shoshonitic series, associated with 134.9–122.9 Ma magnetite–apatite deposits. A-type granitoids and associated alkaline volcanic have a small age range from 126.5 to 124.8 Ma and are temporally, spatially and genetically associated with the second episode. The geodynamic history of the YRB did not experience the Paleozoic to Mesozoic lithospheric thickening that took place in the North China craton. This process is inferred to be linked to partial melting of the delaminated lower crust at high pressures, resulting in the development of C-type adakitic rocks. The petrochemical and Sr/Nd isotopic data show that both the shoshonitic series and A-type granitoids are quite different from adakites, with only some of the K-calc-alkaline granitoids having adakitic signatures. Previous ore genesis models were established based on an assumed relationship with adakites and a continuous tectono-thermal evolution from 150 to 100 Ma.All data obtained for the Middle–Lower Yangtze River region consistently show that the Tan–Lu regional strike-slip fault zone, initiated at 233 ± 6 to 225 ± 6 Ma from the collision between the North China and Yangtze cratons and was reactivated at ca. 160 Ma. The Tan–Lu fault was caused by the oblique subduction of the Izanagi plate, which along the YRB the low-angle subducted slab and the overlying crust was disrupted or broken due to the disharmonious movement of the two blocks. The high-K calc-alkaline granitoids magmas were derived from melting of the subducted slab, with some input of crustal material. These magmas were emplaced at the intersections between NE- and EW-trending faults and formed porphyry–skarn–stratabound Cu–Au–Mo–Fe deposits between 156 and 137 Ma. After 135 Ma the subducted plate changed its direction of motion to northeast, now running parallel to the Eurasian continental margin, and leading to large-scale continental extension. The shoshonitic series and subsequent A-type granitoids magmatism and the development of magnetite–apatite ores in the YRB, took place in both fault basins and NE-trending rifts between 135 and 124 Ma.  相似文献   

滇东南老君山地区印支期成矿事件初探——以新寨锡矿床和南秧田钨矿床为例   总被引：13，自引：1，他引：12  

冯佳睿  毛景文  裴荣富  李超 《矿床地质》2011,30(1):57-73

老君山地区是滇东南多金属成矿带的重要组成部分,但对该区典型矿床精确的成矿时代和构造背景的研究较少.文章选择与锡石密切共生的金云母及与钨矿共生的辉钼矿为研究对象,分别运用40Ar-39Ar阶段加热和Re-Os同位素定年方法,对新寨锡矿床中的金云母及南秧田钨矿床中的辉钼矿进行了成矿时代的研究,获得了金云母的40Ar-39A...  相似文献   

滇东南老君山南秧田钨矿床的成矿流体和成矿作用   总被引：7，自引：2，他引：5  

冯佳睿  毛景文  裴荣富  李超 《矿床地质》2011,30(3):403-419

南秧田钨矿床位于滇东南老君山钨锡多金属成矿区.矿体形态简单,主要呈层状和似层状,在空间上与矽卡岩密切相关.该矿床的形成经历了矽卡岩期和石英硫化物期,前者可分为矽卡岩阶段和退化蚀变阶段,后者可分为石英硫化物阶段和方解石硫化物阶段.白钨矿主要形成于退化蚀变阶段.文章对南秧田矽卡岩型钨矿床内不同成矿阶段的石榴子石、绿帘石、石...  相似文献   

地矿钻探井漏特点及复合堵漏技术   总被引：3，自引：0，他引：3  

毛洪江 《地质与勘探》2011,47(4):686-691

分析了地质情况所引起的渗透性漏失、中微裂缝性漏失、大裂缝溶洞性漏失和破裂性裂缝漏失的特点,研究了水化膨胀复合材料体系的膨胀性、复合桥接堵漏模拟实验及矿场试验,实验结果表明,堵漏材料PAR具有很强的吸水膨胀性能,可膨胀至原体积的几十倍,且时间快,有利于形成快速的封堵,材料PAR与稻谷和锯木形成的复合堵漏材料在承压堵漏测量...  相似文献   

地震灾区四川省松潘县分散安置点地质灾害危险性评估方法概要     

毛建国 《安徽地质》2011,21(4):293-295

四川省松潘县是安徽省在"5.12"汶川大地震之后,对口援助县。安徽省国土资源厅技术援助组代表国土资源部门进行了技术援助。其中,开展了"分散安置点建筑用地地质灾害危险性评估"工作。由于时间紧迫,工作任务属特事特办,所以技援组工作人员采取定性评估和简化评估程序等方法,较圆满地完成了地灾评估工作。对于应急情况下的地灾评估工作,不失为一种新的尝试。  相似文献   

CSAMT法在断层含水性评价中的应用   总被引：1，自引：0，他引：1  

朱金华  冒我冬  白锦琳  李华 《物探与化探》2011,35(4)

在河南省平顶山地区小屯正断层上进行勘查,采用CSAMT法对落差较大断层的含、导水性进行了测量,结果表明该法不仅可以有效控制断层的空间位置,而且可以定性判断断层的富水性。说明CSAMT法的应用在断层含水性评价方面有积极的效果。  相似文献   

测高数据不准时的直升机航空瞬变电磁一维反演方法理论研究   总被引：1，自引：0，他引：1  

毛立峰  陈斌  吕东伟 《物探与化探》2011,35(3):402-405

航空电磁勘探中,高度计显示的发射线圈高度数据往往是不准确的,这可能会影响反演结果,出现假异常现象。针对这一情况,提出了一种高度计数据不准确条件下的航空瞬变电磁资料一维反演方法,在重构地电参数的同时也对发射线圈高度值进行校正。由于航空电磁反演问题是典型的病态问题,使用正则化反演方法,正则化因子由数据目标函数与模型目标函数之间的关系以自适应方式给出,使得反演迭代能稳定进行。以直升机航空瞬变电磁资料反演为例,用理论模型响应数据加入噪声进行反演,结果表明,无论初始高度值是高于真值还是低于真值,该反演方法均能够较好地重构地下介质参数和发射线圈高度值;作为反演初值的发射线圈高度测量值越准确时,反演迭代收敛速度就越快,反演效果也越好。  相似文献