隧道单层衬砌设计方法研究及应用

目前,在单层衬砌设计中应用较为广泛的是基于挪威法的Q系统支护设计法,但该方法涉及的参数有6个,在施工前及施工过程中测试这些参数经验性较强,准确性不高,而且费用较高;将Q法直接移植到中国的单层衬砌设计困难较大,不适合中国国情。在此背景下,提出以屈服接近度和围岩松动圈支护理论为基础的单层衬砌设计原则和方法,并结合合武铁路大别山隧道2号斜井进行了工程实践。首先通过地质勘查得到隧道所在地区的工程地质、水文地质特征以及围岩的物理力学指标,确定隧道围岩的屈服接近度,进而提出单层衬砌支护参数及喷射混凝土的力学控制指标,完成结构的预设计;根据隧道施工过程中实测的围岩松动圈范围,运用松动圈支护理论修正设计,从而形成一套完整的单层衬砌设计方法体系。实践表明,提出的单层衬砌设计方法经济适用、对施工干扰小,适合信息化施工,且施作完成的单层衬砌结构安全可靠,具有显著的经济效益和社会效益,有较大的推广前景。     

井底压力对岩石破碎的影响机制及应用研究

钻井液井底压力与地层孔隙压力是影响岩石破碎的重要因素,由于岩石具有一定的渗透率,在压力差的作用下钻井流体与地层流体之间会相互影响,导致靠近井底的地层孔隙压力发生变化。实际的地层孔隙压力随时间与距离变化的规律可以使用一维不稳定渗流模型来描述和计算。在此分析基础上,综合分析地应力、井底压力及钻头牙齿吃入地层产生的应力,计算出任意平面上所受的剪应力和正应力,然后使用摩尔–库仑准则来判定岩石的破坏。建立这样一个综合各种因素的井底岩石破碎模型,可以将各种因素尤其是实际井底压力差的作用清楚地表达出来。该模型可以较好地解释欠平衡钻井提高钻速的力学机制,并为随钻地层孔隙压力监测dc指数法的适用范围提供明确的计算方法     

黄土结构性力学特性研究与应用的探讨

大孔隙、高孔隙比、欠压密的非饱和黄土具有显著的结构性,结构性是影响土力学性质的关键因素。在讨论土结构性力学特性研究途径的基础上,从反映土的结构可稳性和可变性的综合结构势出发,阐述了反映力、水作用的黄土压缩变形结构性参数、应力结构性参数和应力比结构性参数,以及与土的物理性质指标对应的反映结构特征的构度。通过黄土的单轴抗压试验、非饱和直接剪切试验、三轴试验和真三轴试验,揭示了结构性参数和构度的变化规律,以及它们分别与强度指标之间的关系,提出了湿、剪变形过程等结构性临界状态的概念。将正常固结土视为结构性参数或构度等于1的无结构性土,在修正剑桥模型的基础上,考虑临界状态线和等向压缩曲线随结构性参数的变化,建立了结构性屈服面方程,为建立结构性弹塑性本构方程打下了基础。同时,阐述了黄土隧道围岩和黄土地基稳定性分析中应用结构性强度变化规律研究成果的途径,深化了黄土体稳定性分析的理论基础。     

MSCTE评价Crohn病活动度指数与Harvey-Bradshaw指数的相关性研究?

目的：探讨MSCTE评价克罗恩病（Crohn）活动指数（CDII）与Harvey-Bradshaw指数（HBI）的相关性。方法：选取2014年7月至2016年3月两家医院病理证实的30例CD患者为研究对象,HBI评分后行MSCTE检查并根据CD影像指数评分表评价Crohn病活动指数,比较CDII与HBI在CD活动度分级差异及相关性。结果：CDII与HBI在CD各分级中比较差异无统计学意义（P>0.05）。Spearman相关分析得出CDII和HBI在CD活动度各级中均有显著相关性。结论：CDII与HBI呈显著相关性,具有较高临床价值。     

GEOMORPHIC FEATURES OF THE SHULE RIVER DRAINAGE BASIN IN QILIANSHAN AND ITS INSIGHT INTO TECTONIC IMPLICATIONS

Because of the strong uplift of the Qilian Shan since late Cenozoic,the drainage basins that are derived from the mountains have undergone strong tectonic deformation.So the typical geomorphology characteristics of these drainage basins may indicate the strong tectonic movement in the region.For example,the Shule River drainage basin,which originates from the western part of the Qilian Shan owns unique geomorphology characteristics which may indicate the neotectonic movement. Stream networks of the Shule drainage basin extracted from the DEM data based on GIS spatial analysis technology are graded into five levels using Strahler classification method.Four sub-catchments,numbered 1,2,3 and 4 are chosen for detailed analysis.Furthermore,the four sub-catchments,the hypsometric integral curves,Hack profiles,SL index and average slope of the Shule drainage basin are determined by GIS tools.In addition,we analyzed the slope spectrum of the Shule drainage basin. The average elevation of the Shule drainage basin is very high,however,the slope of the drainage basin is very low,the gentle slope occupies so large area proportion that the slope spectrum shows a unimodal pattern and a peak value is in low slope region (0°~5°),so tectonic movement has a strong influence on the drainage basin.Under the intensive impact of the tectonic movement of the active fault and regional uplift,the hypsometric integral curve is sigmoid,revealing that the Shule drainage basin is in the mature stage.The Hack profile is on a convex,the longitudinal profile is best fitted by linear fitting and the abnormal data of the SL index of the Shule River has a good fit with the section through which the active fault traverses,that means the tectonic movement of the active fault has strong influence on the river's SL index.It is worth noting that lithologic factors also have great impact on the river geomorphology in some sections. According to the above analysis,we recognize that in the interior of active orogen,the evolution of river geomorphology usually is influenced by tectonic movement and reveals the regional neotectonics in turn.     

Graphical methods of river profile analysis to unravel drainage area change,uplift and erodibility contrasts in the Central Range of Taiwan

To reveal river channel steepness patterns and variance in settings with significant variation in rock uplift rate, rock erodibility and moving water divides, we present a series of graphical methods to interpret channel profiles. To complement Cartesian χ plots, longitudinal profiles and mapping methods, we introduce a new method based on a radial coordinate system. We map each basin onto polar coordinates in which the radial dimension is χ and the azimuthal coordinate, ?, is calculated with an increment (Δ?) scaled to the distance to neighboring channel heads. The elevation is contoured on this mapping. Average channel steepness is estimated by fitting a conical surface to the elevation. The graph simplifies the comparison of χ and elevation between channels that share a divide, and helps identify spatial changes in drainage area and patterns of erodibility. We apply this approach to derive the uplift pattern in the eastern and southern Central Range of Taiwan, where the high tectonic convergence and uplift rates combined with sub‐tropical climate and frequent typhoons results in high exhumation rate, and well‐developed, detachment‐limited river networks. Additionally, the tectonic activity leads to drainage basin reorganization. We identify examples of divide migration, discrete river capture as well as anomalous steepness that we attribute to local variability in rock erodibility. Estimated basin‐average steepness values show the highest and a near constant value from Hsinwulu basin to Liwu basin in the center of the Island. To the north and south of this region, the values gradually decrease. These estimates show good correlation with the topography of the Central Range and erosion rates derived from in situ ¹⁰Be concentrations in river‐borne quartz. We conclude that the basin steepness reflects systematic differences in rock uplift rate and erosion rate. Copyright © 2016 John Wiley & Sons, Ltd.     

基于Copula函数的CFG桩复合地基载荷-变形曲线的概率分析

CFG桩(cement-fly ash-gravel pile)复合地基是一种重要的地基处理形式,在日益增加的大面积住宅和商业开发中作用越来越突出,然而该种桩型的加卸荷-沉降变形特性仍然需深入研究,尤其在概率评估方面。根据北京星光影视股份有限公司生产科研基地项目工地中的21根CFG桩单桩静载试验和32个复合地基静载试验的原位加卸载测试成果,采用两参数的双曲线或幂曲线回归拟合了每一条加荷-变形曲线。由于土体的内在各向异性和其强度的变异性,评估整个场地的加荷-变形曲线时,其回归参数表现出了较大的离散性。将一个场地的多组回归参数组成一个随机向量,其加载-位移曲线的不确定性可由简单的两变量随机向量体现,引入双变量联结函数（Copula）描述随机回归参数间的相依性。最后,考虑正常使用极限状态,采用基于Copula函数的模拟模型计算了CFG桩复合地基的可靠度指标。研究结果有助于改进CFG桩复合地基的概率设计与评估。     

高原湖相泥炭土渗透特性研究及机制分析

为明确高原湖相泥炭土渗透特性并建立渗透模型,采用固结-渗透联合试验装置对取自6个场地20余组土样天然状态及一维压缩过程中渗透系数进行测定,并分析了加载时长、应力水平以及烧失量、残余纤维含量等因素对其渗透性的影响。试验结果表明：分别加载条件下,泥炭土渗透系数 随加载时长T增大而减小并趋于稳定,稳定时长在10 d左右;分级加载条件下, 随固结应力 的增大呈非线性减小, - 关系曲线为反S型;高原湖相泥炭土渗透模型可用e- 表示,其渗透指数 与初始孔隙比 满足关系式 0.25 ;初始渗透系数 和烧失量 、残余纤维含量 及 关系较为离散, 和 、 及初始含水率 有一定的正相关性。通过电镜扫描试验,从土中孔隙特征角度探讨了高原湖相泥炭土渗透特性的机制。     

截齿破岩机制及截线间距优化试验研究

根据截齿侵入岩石的断裂特征和相关试验数据,分析了破岩机制及不同截线间距对破岩效果的影响。在单刀旋转截割试验平台上,以不同切削深度和截线间距进行组合试验,并结合比能耗、粗度指数及截割载荷3个评价指标,对截线间距进行优化,研究截割该类型砂岩时截线间距与切削深度的最佳比值。试验结果表明,岩石在单齿旋转截割作用下的破碎过程大致可以分为初始压碎区细粒岩屑生成、密实核形成并储能、各向裂纹的扩展与连通、断裂体崩落、二次压碎区细粒岩屑生成5个阶段,且岩屑的断裂是以拉伸为主并伴随着挤压和剪切的共同作用;在最佳截割条件下,粗度指数较高,岩屑成块率增加,且比能耗低。通过分析岩石破碎过程及对截线间距的优化,可为掘进机破岩机制研究及截齿布置提供参考。     

基于多源遥感数据的高山峡谷区岩性信息提取研究——以新疆乌什县北山1:50000填图试点为例

新疆乌什县北山1:50000填图试点项目位于塔里木盆地西北边缘和西南天山交接部位,海拔较高,地形切割较深,属于典型的高山峡谷区。利用ASTER、SPOT6、GF-2等多源遥感数据,基于典型岩性光谱吸收特征,进行岩性差异信息增强与提取研究,总结出一套基于多源遥感数据进行岩性单元边界划分的方法。以ASTER数据、ASTER与SPOT6协同数据、ASTER与GF-2协同数据等为基础影像数据,并选择最佳波段组合进行RGB彩色合成,从而增强影像差异,结合已有研究区地质资料,初步圈定不同影像单元边界;继而利用矿物丰度指数、SMACC端元丰度提取等方法识别研究区内主要岩性的分布位置和范围;最后结合野外实际调查数据,依据实际地质背景和影像质量进行筛选,获得最终的岩性单元解译图。研究结果为该区进一步进行地层优化划分及对比提供了参考资料。