In borehole monitoring for deep displacement, the abrupt characteristics of inclinometer curves are the key basis for identifying the sliding surface. Previous studies have summarized several types of inclinometer curve patterns that exhibit significant sliding surface signals, including "B," "D," and "r" types. For "D" type inclinometer curves, the convex point of the curve is typically used as the position of the sliding surface. However, this method is susceptible to the influence of observation points spacing and coordinate observation scales, which can result in an unclear definition of the sliding surface position and uncertain numerical values. To overcome these drawbacks and improve the accuracy of sliding surface identification in inclinometer curves, a generalized model of landslides composed of “sliding body”, “sliding interval,” and “immovable body” was developed based on the variation characteristics of the "D" type inclinometer curve. A mechanical strut model subjected to external loads was established based on the different flexural rigidity of the three members, and the deformation characteristics of soil at different depths during landslide movement were analyzed in depth. The study found that the sliding surface of "D" curve does not entirely penetrate, leading to continuous soil deformation along the depth direction without abrupt change. The demarcation point of the positive and negative bending moments in the mechanical model is a location where the horizontal displacement of deformation curve is the largest, which can reflect the real deformation characteristics of the landslide and the position of the sliding surface. By converted the accumulated soil displacement into relative displacement, the "D" type inclinometer curve is transformed into "S" type relative displacement-depth curve, and the inflection point of the "S" type curve is close to the position of the sliding surface. By extracting the average relative displacement of soil at different depths during the monitoring period and calculating the depth value of the inflection point in the "S" type segment by using the cubic spline interpolation method, the position of the sliding surface can be determined more accurately, which can greatly improve the reliability and accuracy of deep displacement monitoring and has significant practical value.
断层泥被公认是记录断层滑动和活动时间的重要信息来源.观测沂沭断裂沿线石英微形貌特征推断断层活动期次及活动方式.沂沭断裂是郯庐断裂向北的延伸,断层泥较为发育.在野外调查的基础上,在沂沭断裂北段的安丘-莒县断裂、昌邑-大店断裂选取了 4 个剖面,对石英颗粒进行了扫描电镜观察及光释光测年分析.结果表明,石英以中度溶蚀Ⅱ类和Ⅰb+Ⅰc型微形貌为主,也出现了Ⅲ型、Ⅳ型、Ⅰa型和Ru型,说明沂沭断裂北段具有多期活动的特征,最近一次较强的运动发生在早-中更新世,晚更新世以来活动过,但不强烈.由断层泥中石英的撞擦特征、破裂特征和形态特征等统计得出,该断裂晚更新世以来以蠕滑及过渡型为主,黏滑较弱.研究结果可为监测研究区的断层活动提供有力支持.
随着我国煤矿相继进入深部开采,三高一扰动复杂应力环境使深部煤岩体结构趋于破碎为块体,煤岩块体界面多为含倾角结构面.冲击扰动作用下,煤岩块体易沿煤岩界面产生失稳滑移,诱发超低摩擦型冲击地压.利用有限差分软件,建立砂岩-煤-砂岩组合块体,以工作块体水平位移、加速度幅值作为块体超低摩擦效应表征参数,模拟不同倾角的煤岩组合块体受扰动冲击作用时,工作块体超低摩擦效应特征参数的变化情况.考虑倾角大小、加载方式、冲击幅值和水平冲击延迟时间等因素影响,得到含倾角煤岩组合块体超低摩擦效应影响规律.研究结果表明:动载扰动下含倾角煤岩组合块体,煤岩块体倾角越大,加速度峰值越大,位移错动越明显,超低摩擦效应越显著.随垂直扰动幅值的增加,工作块体加速度振荡越剧烈,趋于平衡收敛时间延长,垂直扰动始终是诱发超低摩擦效应的主要因素.垂直扰动与水平冲击共同作用下,模型底部、中部、顶部监测点超低摩擦效应强度依次增加,随着倾角的增加,位移差值不断扩大.工作块体位移振荡剧烈程度随水平冲击延迟周期增加而增大,在同一位移振荡周期内,波峰点水平冲击比均值点与波谷点水平冲击更易发生超低摩擦效应.
地铁隧道等长线性工程结构因功能需要,不可避免地跨越活动断层,一旦断层错动将可能产生严重后果.断层错动引发的地表位移可作为近地表长线性工程结构抗断设计的输入依据.其中,覆盖土层对地表位错量的影响不可忽略.鉴于此,采用有限元数值模拟方法,基于试验校准模型,研究了基岩断层错动下上覆土层厚度和土体性质等因素对地表位移的影响,提出了考虑倾滑断层上覆土层影响的地表位移概率地震危险性分析方法.研究结果可为跨断层近地表长线性工程结构抗断设计提供支撑.
供水管网是城市生命线工程的重要组成部分,大区域城市供水管网地震灾害风险评估是进行区域地震灾害风险区划及对策制定的重要基础性工作之一.目前,国内学者针对我国供水管网给出了不同材质管道的地震易损性模型,但尚未对不同区域城市的供水管网整体进行分区分类的地震易损性研究,限制了大区域供水管网地震灾害风险评估工作的顺利实施.基于这一研究现状,利用东北地区部分城市管网结构组成及规模基础资料,结合不同材质管道的地震易损性,对东北地区城市管网综合抗震能力进行分类,建立了 5 个不同抗震能力类别城市供水管网的地震易损性模型,为缺少基础数据支持城市的供水管网地震灾害风险评估提供了参考地震易损性模型.
