肥槽回填土常见工程问题与处理方法

总结分析了建筑工程肥槽回填土质量不良引发的常见工程问题,以及肥槽回填土不易施工密实的几个主要原因,并总结提出了各种肥槽回填土处理方法,以及它们主要的适用条件。     

渠式切割水泥土连续墙（TRD工法）及其工程应用

渠式切割水泥土连续墙（简称TRD 工法）是近几年从国外引进的一种新型地下水泥土墙的施工方法。结合工程实例,对TRD工法的成墙原理、施工工艺、施工要点、适用范围等进行了介绍,并对TRD工法在实际应用中的优缺点进行了分析。工程实践证明,TRD工法在基坑工程挡土及隔渗止水方面具有明显的技术优势。     

南海南北陆缘中生代地层—构造特征及碰撞造山

为进一步深入了解南海地区中生代构造演化过程.本文对南海南北陆缘的中生代地层进行了分析对比,在此基础上挑选了南北陆缘处的两条地震测线07ns-6和97301进行了详细的解释分析.通过地震剖面的解释发现,南海北部和南部(礼乐地块)地震剖面中的中生代地层均显示有褶皱—冲断构造发育.据此推断,研究区在中生代先后经历了洋—陆俯冲活动、陆 陆碰撞造山运动及中生代晚期开始的造山带的塌陷.提出南海地区中生代晚期的“古双峰笔架碰撞造山带”概念.     

Effects of open trench siding on vibration-screening effectiveness using the two-dimensional boundary element method

The two-dimensional boundary element method in frequency domain is used to investigate the screening effectiveness of the open trench–wall barrier system on reducing vibration generated by a footing. Sheet piles or diaphragm walls are on both sides of the open trench as a vibration barrier in this study. The results showed that screening effectiveness of the open trench without siding is greater than that of the open trench–wall barrier system, which is essential for stabilizing the excavation surface in practice. The trench depth of the barrier system appears to govern the screening efficiency of the barrier, and increase in depth results in better vibration-screening effectiveness. The influence of the open trench width, the embedded length of the trench wall and the distance between the vibration source and the barrier are proven to be insignificant. The screening effectiveness of an open trench barrier with walls increases with the frequency of the vibration.     

公元512年山西省北部7.5级地震发震断层初探

根据野外断层露头,探槽及热释光年龄样数据,揭示了大同盆地内黄花梁－山自皂断层为公元５１２年强震的发震断层,这对确定该次地震宏观震中及研究大同盆地地震活动性具有重要意义。     

From incipient island arc to doubly‐vergent orogen: A review of geodynamic models and sedimentary basin‐fills of southern Central America

Southern Central America is a Late Mesozoic/Cenozoic island arc that evolved in response to the subduction of the Farallón Plate beneath the Caribbean Plate in the Late Cretaceous and, from the Oligocene, the Cocos and Nazca Plates. Southern Central America is one of the best studied convergent margins in the world. The aim of this paper is to review the sedimentary and structural evolution of arc‐related sedimentary basins in southern Central America, and to show how the arc developed from a pre‐extensional intra‐oceanic island arc into a doubly‐vergent, subduction orogen. The Cenozoic sedimentary history of southern Central America is placed into the plate tectonic context of existing Caribbean Plate models. From regional basin analysis, the evolution of the southern Central American island arc is subdivided into three phases: (i) non‐extensional stage during the Campanian; (ii) extensional phase during the Maastrichtian‐Oligocene with rapid basin subsidence and deposition of arc‐related, clastic sediments; and (iii) doubly‐vergent, compressional arc phase along the 280 km long southern Costa Rican arc segment related to either oblique subduction of the Nazca plate, west‐to‐east passage of the Nazca–Cocos–Caribbean triple junction, or the subduction of rough oceanic crust of the Cocos Plate. The Pleistocene subduction of the Cocos Ridge contributed to the contraction but was not the primary driver. The architecture of the arc‐related sedimentary basin‐fills has been controlled by four factors: (i) subsidence caused by tectonic mechanisms, linked to the angle and morphology of the incoming plate, as shown by the fact that subduction of aseismic ridges and slab segments with rough crust were important drivers for subduction erosion, controlling the shape of forearc and trench‐slope basins, the lifespan of sedimentary basins, and the subsidence and uplift patterns; (ii) subsidence caused by slab rollback and resulting trench retreat; (iii) eustatic sea‐level changes; and (iv) sediment dispersal systems.     

南海东部现时地壳运动、震源机制及晚中新世以来的板块相互作用

南海东部的板块汇聚带是了解南海和菲律宾海晚中新世以来构造演化的一个重要窗口.针对这一区域地壳运动的研究,获得了该区内微块体的现时地壳运动特征及其动力机制,在此基础上结合俯冲板片形态和震源机制资料提出了该区晚中新世以来的板块汇聚作用特征.研究发现:晚中新世晚期,菲律宾海板块西缘在南、北部的西向运动均受到限制的情况下,位于中间区域的吕宋岛北部则由于其西侧相对自由而继续往NW方向运动.该过程中,菲律宾大断裂等汇聚带内部的走滑断裂对于协调不同块体之间的地壳运动速度差异有着重要作用.受南、北阻挡的影响,中间部分的西向运动速率呈现出中间大(吕宋岛北部)两端小的特征.因而北吕宋西侧的马尼拉海沟也以相对于南部更快的速率不断向NW迁移.然而俯冲的南海岩石圈受其下方SE向地幔流的影响,未能发生相应的俯冲板片后撤,而是在两板块之间的直接接触面形成强烈推挤并发生反向弯曲.结合这一板块作用特征认为,马尼拉海沟现今的构造形迹是在上述背景下北段多次向NW方向变迁形成的,而双火山弧的形成则主要是由菲律宾海板块在吕宋岛弧南、北部的西向运动速率差异引起的.     

太山龙泉寺舍利塔边坡地震稳定性研究

为了研究太原市太山龙泉寺拟建舍利塔边坡稳定性,对所在场地及外围地形地貌、地层、地质构造、水文条件进行了调查。结合7个探井,确定了塔址所在场地的土质边坡体可能失稳的模式,进行了边坡稳定性分析、计算。结果表明,场地在自然状态下边坡稳定系数为1.37,在烈度为Ⅷ、Ⅸ度地震影响下边坡稳定系数分别为1.24、1.15。根据《建筑边坡工程技术规范》（GB50330-2013）,塔址所在边坡是稳定的,不必对边坡进行处理;其次结合3个探槽揭露,发现场地北侧基岩边坡曾发生过滑动,据其滑动面倾角、滑动量及错断地层特征,认为是一种特殊边坡变形破坏-岩体错落,为崩塌与滑坡之间的中间类型,从现存的地形地貌特征分析,现阶段错落体已趋于基本稳定状态,稳定性较好;最后给出了预防边坡滑动的建议和措施,研究结果可为其他类似边坡场地地震稳定性研究提供参考借鉴。     

高分辨率遥感数据处理及其铀矿地质应用

高光谱和高空间分辨率遥感技术在铀矿地质勘查中具有重要作用,遥感数据挖掘与知识发现、新方法研究则是各种铀成矿要素光谱信息和空间特征识别的关键技术手段。本文基于曲波变换技术,开发了卫星高光谱数据（Hyperion）和高空间分辨率（SPOT5）的影像融合方法,融合影像在数据噪声消除、信息增强与信息提取方面应用效果显著;利用离散小波变换技术,高精度提取了主要铀成矿要素的光谱参数,建立了典型四价和六价铀矿物的光谱识别谱系。另外,通过钻孔岩心和探槽工程的高光谱编录、地质编录和物探编录,建立了典型蚀变带的物谱关系模型,重点分析了赤铁矿化蚀变（Fe3＋）光谱特征与铀含量之间的相关关系。上述遥感数据处理新技术新方法在桃山地区铀矿地质勘查中取得了理想效果。     

利用现代地形资料鉴定断层活动性

本文述及场地断层活动性与地震地质背景的问题。工程场地内存在若干条印支—燕山期逆断层。对探槽揭露的断层分析表明,这些断层自晚更新世以来未发生新活动。同时对场地及附近地区层状的夷平面、喀斯特溶洞及河谷侵蚀一堆积阶地等现代地形,进行地貌调查、第四纪地层分析和相应的计算,进而认为,这些断层自晚中更新世以来未发生新活动。因此,就断层活动性而论,该场地是适于工程建设的。 现代地形资料可资鉴定断层活动性