A Comparative Visualization Strategy of Probabilistic Susceptibility Maps for Analyzing Different Types of Slope Failures

This paper presents a comparative visualization strategy of slope failure susceptibility maps for analyzing different types of simultaneous occurrences of slope failures. Through the SEM （structural equation modeling）, slope failure susceptibility maps are produced by using causal factors （i.e., geographical information, satellite remotely sensed data）. As for a conventional pair-wise comparative procedure, the differences between susceptibility maps are delineated on difference maps, that can be, however, applied for evaluating differences only between pairs of susceptibility maps. One of the strong requirements from specialists working on slope stability evaluation is a comparative and visualization strategy of susceptibility maps with respect to ＂different types of simultaneous slope failures＂, for which the discussion is insufficient in the previous research activities for constructing the quantitative models for slope failure hazard mapping. As a measure, a color composite map based on susceptibility maps has been produced. The combination of assigning susceptibility maps to RGB-color planes is determined based on an index of ＂NCCT （normalized correlated color temperature）＂ which represents the relationship between chromaticity and human visual perception. Through the cases examined, the result indicates that the proposed color composite map, as a heuristic visualization strategy, is useful for simultaneously evaluating the hazardous areas affected by ＂different types of slope failures＂.

浙江省山区输电线路塔位边坡变形破坏主要类型与防治建议

山区输电线路铁塔基础施工改变了塔位附近原始微地形、覆盖植被等环境地质条件,岩土体内部原有应力状态发生了变化,在各种自然营力作用下,每年在浙江省山区会发生一定数量塔位边坡的变形与破坏。根据影响因素、变形破坏机理分析,结合现场勘查及实际情况,划分为坍塌、滑坡、流坍等边坡变形破坏类型,经研究总结得出其主要发育特征,并提出了防治建议。

Sustainable land-use patterns for arid lands: A case study in the northern slope areas of the Tianshan Mountains

Sustainable land use patterns are ecological and economic prerequisites of regional sustainable development. This is especially true for arid lands, where the environment is wholly fragile thanks to extremely limited precipitation, and where human activities have greatly transformed natural desert system by clearing natural vegetation, expanding oases and even building dams on inland rivers. However, the current studies on land use patterns are still characterized by field investigations and case studies, with almost no solid scientific basis. This paper holds that land types and their combination patterns are the principal basis for designing sustainable land use patterns, and that GIS and RS-based large-scale land type mapping and the study of their spatial combination structures should be coordinated with the demand of social development. The existing environmental problems induced by irrational land use mostly result from their deviation from the natural properties of land types. Taking the northern slope of the Tianshan Mountains （NSTM） as an example and considering land type patterns as the basis of land use patterns, this paper improves the vertical oa- sis-and-mid-mountain two-belts development model and the sustainable mountain land use model for arid lands put forward in recent years; and in terms of oases patterns, it outlines oasis development models, including intensive land use pattern in alluvial-diluvial fans, moderate agricultural development pattern in alluvial plains, and ecological land use pattern in river-end oases.

Experimental Study of Runoff Coefficients for Different Hill Slope Soil Profiles

The estimation of peak discharge from a catchment due to intense rainfall is a difficult task that may occur in a return period. If cannot be estimated accurately, it may lead to serious problem in hydraulic structure design like bridge, culvert across a river and drainage system. The main parameter which affects the peak flow is runoff coefficient of the catchment which directly depends on the soil type, its slope and land use pattern with vegetation covers. For the purpose, this study was carried out to estimate maximum runoff coefficients for different land profiles and soil types in hill slope model developed in 10 degree with the horizontal to the rainfall simulator rig (Basic Hydrology system-S12) experimentally which can give more reliable value than the real field test method as it is easier than field test especially in hill slope. The soil slope preparation was made of sand, silt and clay separately and the experiments were carried out in a controlled system. The slope prepared represented a small catchment on a plot of 2.02 meter length, 1 meter wide and 0.15 m depth soil plots (at the slope of 10° to the horizontal plane). From the experiment in different soil plots, the rainfall runoff coefficients were observed as 0.428 - 0.53 for sand soil slope, 0.46 - 0.55 for silt soil slope and 0.42 - 0.51 for clay soil slope under uniform rainfall rate of 4 lpm to 13 lpm in each soil slope. Rainfall runoff correlation equation was found with the values of R above 90% in each soil slope. The value observed is within the range of rational value of 0.05 to 0.95 as standard which concluded that the performance of simulator was found good to deal with rational values. And the runoff coefficients for these soil types can be taken within the range obtained to estimate peak discharge in any small catchment area depending on the soil types.

Geochemical characteristics and oil family classi-fication of crude oils from the Markit Slope in the southwest of the Tarim Basin, Northwest China

Based on the chromatograms of oils and saturated hydrocarbons, biomarkers and stable carbon isotope analyses, the geochemical characteristics and oil family Classification of crude oils from the Markit Slope in the southwest of the Tarim Basin were investigated. The results showed that crude oils from the Markit Slope are divided into two oil family Classification. Oils collected from the Bashituo oilfield in the western part of the Markit Slope are characterized by high contents of tricyclic terpanes, pregnane, and homopregnane, low contents of garmmacerane (G/H<0.20), dibenzofuran, and methyl cyclohexane, and light stable carbon isotopic values (the δ13C values of satu-rated hydrocarbons and aromatic components are less than -34‰ and -32‰, respectively), with the distribution type of steranes being C27>>C28<C29. Condensate oils collected from the Hetian River gasfield in the eastern part of the Markit Slope are characterized by low contents of tricyclic terpanes, pregnane, and homopregnane, high contents of garmmacerane (0.20<G/H<0.36), dibenzofuran, and methyl cyclohexane, and relatively heavy carbon isotopic values (δ13C of saturated hydrocarbons and aromatic components (> -32‰ and -30.6‰, respectively), with the distribution type of steranes being C27>C28<<C29. In addition, oils from Well Qu 1 have some characteristics similar to those of the above oils, with some special characteristics including high contents of β-carotenes and special distribution of steranes (C27<C28 <C29).

曲面滑坡条件下h型抗滑桩受力性状模型试验研究

依托公路大型滑坡治理工程,设计物理模型试验装置,设置同一滑面和桩体锚固深度,进行6组h型抗滑桩室内模型试验,分析不同连梁长度及后排桩悬臂段高度(连梁高度)时桩顶位移变化规律、桩身弯矩和桩后土压力分布特征,研究曲面滑坡条件下h型抗滑桩受力性状及其内在机制,并给出桩后滑坡推力抛物线型分布的一般函数表达式。试验结果表明:h型抗滑桩受力过程桩顶水平位移变化表现出较为明显的三阶段特征,桩身弯矩分布呈现正、负交变现象,后排桩桩顶水平位移及桩身弯矩明显大于前排桩;降低后排桩悬臂段高度不影响桩身弯矩分布特征,但对于桩顶水平位移及桩身弯矩量值,后排桩明显减小,前排桩有所增大;增减连梁长度对前、后排桩之间荷载传递与协同受力特性影响显著,使得前、后排桩水平变形及桩身弯矩随之产生变化;连梁正、负弯矩极值均处于连梁端部,相比于连梁长度,连梁弯矩的大小及分布形态受后排桩悬臂段长度的影响更为明显;随着连梁长度的减小或后排桩悬臂段长度的增加,后排桩桩后土压力表现出抛物线型、重心偏下的抛物线型及近似梯形的分布形态。此外,给出的滑坡推力函数表达式能较好的表征其抛物线型分布特征,通过调整合力作用点参数,亦可对滑坡推力近似梯形的分布类型进行描述。

隆起对砂岩型铀矿成矿的控制及找矿启示

沉积盆地古隆起对油气成藏起到明显控制作用,对砂岩型铀矿成矿的制约也不可忽视。砂岩型铀矿通常就位于盆地边缘构造斜坡带和盆地内部隆起附近。隆起对砂岩型铀矿成矿的控制具体体现在:控制地下水补-径-排体系、控制层间氧化作用、控制沉积相带发育、伴生断裂促进物质输运以及为成矿供给铀等。中国北方沉积盆地中新生代以来经历复杂的构造活动,盆地域内非均衡发展而多形成隆起,因此我国铀矿找矿尤其需要重视隆起对铀成矿的控制。其中,盆地内部找矿应重点关注被大幅抬升的隆起,而盆地边缘构造斜坡带上找矿需重视微隆起以及基底上覆地层的褶皱。将隆起作为关键控矿要素,优选适用的攻深找盲方法,精细刻画盆地基底隆升形成的背斜、褶皱及伴生断裂,可有效提高铀矿找矿效率并拓展铀矿找矿空间。

气体地球化学勘查在巴—麦地区砂岩型铀矿找矿中的应用

塔里木盆地内部砂岩型铀矿找矿十分迫切。针对该盆地地质构造相对复杂、沉积地层厚度大、勘查手段受到沙漠-荒漠地貌的限制、勘查程度较低和地表成矿信息弱的特点,在巴楚隆起—麦盖提斜坡带地区(巴—麦地区)开展能指示深部地层环境的H_(2)S、CH_(4)、H_(2)、CO_(2)和4He气体地球化学区域测量研究。结果表明,几种土壤气体浓度能够较为清晰地显示各自异常分布范围,并指示盆地地层中可能的铀异常信息,气体地球化学测量方法是一种相对高效的盆地区域地表勘查方法。在综合测区断裂分布、油气藏、水文等地质条件和气体化学反应性质的基础上,分析气体浓度异常成因及分布综合特征,测区东北部、东南部及色力布亚断裂和巴什托断裂所夹持部分地段具有几种气体组份浓度异常叠加,地层中可能发育氧化-还原地球化学障,是有利的找矿预测区,为该地区砂岩型铀矿勘查提供参考依据。

Origin and migration model of natural gas in L gas field, eastern slope of Yinggehai Sag, China

Based on the chemical and stable carbon isotopic composition of natural gas and light hydrocarbons, along with regional geological data, the genetic type, origin and migration of natural gases in the L lithologic gas field, the eastern slope of Yinggehai Sag were investigated. The results show that these gases have a considerable variation in chemical composition, with 33.6%–91.5% hydrocarbon, 0.5%-62.2% CO2, and dryness coefficients ranging from 0.94 to 0.99. The alkane gases are characterized by δ13C1 values of -40.71‰--27.40‰,δ13C2 values of –27.27‰– –20.26‰, and the isoparaffin contents accounting for 55%–73% of the total C5–C7 light hydrocarbons. These data indicate that the natural gases belong to the coal-type gas and are mainly derived from the Miocene terrigenous organic-rich source rocks. When the CO2 contents are greater than 10%, the δ13CCO2 values are –9.04‰ to – 0.95‰ and the associated helium has a 3He/4He value of 7.78×10^–8, suggesting that the CO2 here is crustal origin and inorganic and mainly sourced from the thermal decomposition of calcareous mudstone and carbonate in deep strata. The gas migrated in three ways, i.e., migration of gas from the Miocene source rock to the reservoirs nearby;vertical migration of highly mature gas from deeper Meishan and Sanya Formations source rock through concealed faults;and lateral migration along permeable sandbodies. The relatively large pressure difference between the “source” and “reservoir” is the key driving force for the vertical and lateral migration of gas. Short-distance migration and effective “source - reservoir” match control the gas distribution.

高原高铁特长和超长隧道单列车通过时空气阻力变化规律研究

为研究列车通过高原高铁隧道时隧道长度、坡型、坡度、海拔和列车速度对列车平均空气阻力、最大空气阻力以及隧道平均空气阻力因子、最大空气阻力因子4个空气阻力指标的影响规律,基于一维可压缩非定常不等熵流动模型特征线模拟隧道压力波,将列车空气阻力分解为头尾车端部的压差阻力、车厢摩擦阻力、全列车压差阻力和列车周围空气重力沿列车运行方向的分量阻力(简称空气重力分量阻力),建立反映坡度的单面坡隧道空气阻力计算模型。研究结果表明:1)单列车通过有坡度隧道时,空气阻力变化规律与车外压力波和空气重力分量阻力有关,受到压缩波和膨胀波的作用增大或减小;单列车通过不同隧道长度的单面上坡/下坡、人字坡和平直隧道时,存在基于平均空气阻力的最不利坡型和临界隧道长度。单列车通过长10 km的单面上坡隧道时平均空气阻力最大,为47.05 kN。2)单列车通过单面上坡隧道时,平均空气阻力和最大空气阻力随着坡度和列车速度的增大而增大,随着海拔的升高而减小。3)通过对平均空气阻力与列车速度拟合得出,列车通过单面上坡、下坡隧道时,平均空气阻力分别与列车速度的1.92次方和2.14次方成正比。

伊犁河谷不同雨型下自然与人工植被的水土流失特征

【目的】为科学防控西北干旱区草地水土流失以及比较不同雨型下植被的径流调控效果。【方法】2021—2022年雨季在伊宁市铁厂沟水土保持径流场,采用K均值方法将研究区13场侵蚀性降雨划分为3类,并监测5种自然植被(霸王、驼绒藜、伊犁绢蒿、骆驼刺、苦豆子)和3种人工植被(榆树、紫穗槐、狗牙根)的产流产沙特征,探讨不同雨型下各植被的产流产沙规律,采用灰色关联度分析雨型和植被小区对产流产沙的影响。【结果】①伊犁河谷土壤侵蚀的主导雨型是B雨型(中雨量、短历时、中雨强),对坡面产流产沙的贡献程度达到53.5%。A雨型(低雨量、长历时、低雨强)和C雨型(高雨量、长历时、高雨强)贡献率较低;②自然植被的减流减沙效益高于人工植被,自然植被在A雨型下减流减沙效益最好(87.3%~95.2%),人工植被在C雨型下减流减沙效益最差(39.2%~52.7%);③降雨量和平均雨强显著影响径流深和土壤流失量(P<0.05),灰色关联度从大到小排序为伊犁绢蒿>苦豆子>霸王>紫穗槐>骆驼刺>狗牙根>榆树>驼绒藜。【结论】伊犁河谷进行植被恢复可有效减少水土流失,不同雨型下自然植被的减流减沙效益优于人工植被,单一植被的减流减沙效益与其覆盖度有关。研究结果可为西北干旱区国土绿化、土地荒漠化和水土流失防治提供理论基础。

h型桩板墙在高速铁路陡坡路基中的应用

以杭黄高速铁路某陡坡路基工点为背景,受地形和周边环境影响,支挡结构悬臂段>13 m,故提出一种h型桩板墙的支挡设计方案,并选择代表性断面开展现场试验研究,测试结构所受土压力、钢筋应力、水平位移,研究结构内力分布规律。研究表明:(1)根据主桩实测土压力分布曲线,横梁上部土压力明显大于下部,说明横梁上设置承载板有显著的卸荷作用;(2)结构各测试部位钢筋应力均远小于设计强度;(3)根据实测钢筋应力反算锚固面位置,当锚固段地层为基岩强风化时,主桩锚固面位置宜在桩前覆盖层2~3 m;(4)各测试断面测试期间主桩桩顶水平位移为2~6 mm,表明结构具有较强的横向刚度。

斜坡—沉积源岩型氦气富集模式——以鄂尔多斯盆地神木气田为例

鄂尔多斯盆地氦气资源丰富,已在伊盟隆起、伊陕斜坡南部等地区发现高含氦、富氦天然气田,这些气田的氦气富集多与断裂发育密切相关。然而,盆地内的构造背景较为复杂,为研究盆地内不同地质背景下氦气的富集特征及控制因素,对鄂尔多斯盆地伊陕斜坡东北部开展天然气组分分析测试,并结合研究区基础地质资料及前人研究成果,对鄂尔多斯盆地神木气田上古生界的氦气分布特征及其地质影响因素进行探究。神木气田上古生界氦气含量达0.017%~0.116%,平均氦气含量为0.05%,达到含氦气田标准;氦气含量在平面上呈“西低东高”的整体分布格局,东部部分地区的氦气含量大于0.1%;氦气含量与氮气含量呈明显正相关关系,表明天然气藏中的氦气和氮气在成因和溶解—脱溶机制上可能存在必然联系。神木气田氦气的富集受多种地质因素共同影响:上古生界广泛分布的煤系烃源岩提供了充足的氦气;地壳抬升和构造反转控制了氦气的运移方向,且促进了溶解氦的脱溶和聚集;适量的载体气有助于氦气的富集。结合研究区构造背景和氦气成藏地质因素,提出了一种新的氦气富集模式,即斜坡—沉积源岩型含氦天然气富集模式,这为氦气勘探和开发工作提供了重要的理论支持。

生态混凝土制备及植生试验研究

传统河道边坡防护通常采用硬性材料硬化边坡以达到加固效果,然而这种作法对河道周边的生态环境造成了巨大的破坏。为此,本试验引入了生态混凝土的概念,将其作为基础材料进行深入研究。以水泥掺量和骨料掺量为影响因素,设计了单因素影响试验,对生态混凝土初期强度进行了详细的分析,并展开了植生试验,以期在实现加固效果的同时最大限度地保护生态环境。结果表明,对生态混凝土强度影响显著性为:水泥掺量>骨料掺量,黑麦草适宜在生态混凝土中生长。

盐渍土地区路基边坡冲刷破坏影响因素

了解水流特征、边坡结构和土质条件对边坡冲刷的影响及其破坏形式,是为盐渍土地区工程设计和施工防护提供科学依据的前提。结合室内试验方法,对盐渍土路基边坡冲刷工程进行模拟。结果表明:水流的冲刷致使路基边坡发生明显的变化,边坡坡脚首先受到水流的影响,其动态过程表征为水流浸泡冲刷—形成淘空槽—边坡上部土体掉落—冲刷深度范围扩大;随着流速、水深增加,坡脚冲刷程度增大,而坡比的影响恰恰相反;此外冲刷角的变化改变了最大冲刷深度出现的位置;相比于NaCl盐渍土路基边坡,Na 2SO 4盐渍土盐量的增加,坡脚处冲刷范围和最大冲刷深度出现呈现相反的减少趋势。

膨胀性裂土病害产生机理及综合防治措施研究

膨胀土是指吸水后显著膨胀、失水后显著收缩的高塑性黏土,随着膨胀土问题的日渐加剧,膨胀土对施工环境的影响已成为当今岩土工程中亟待解决的全球性技术难题之一。在文献调研、资料收集及成果汇总的基础上,对膨胀土的基本性质、胀缩机理进行了总结,从病害产生部位、形态特征、成因及破坏速度等角度系统划分了膨胀土“四类”破坏类型;通过堑坡深度、垂直方向、坡顶及坡底水平方向变形量提出了膨胀土堑坡“四个”活动层面;结合膨胀土地区路基、边坡、建筑物及其他各类病害特点,总结了相对应的技术措施,研究成果对于膨胀土地区在建和拟建工程有参考意义。

边坡修复中边坡类型及绿化植物对目标群落有效性的研究

【目的】研究绿化植物和受损边坡对生态修复的有效性,探索重建目标植物群落的主要依据。【方法】用AHP方法分析绿化植物和受损边坡在边坡修复中的有效性,按有效性排序选择先锋和建群种植物构建目标植物群落。【结果】受损高速公路边坡体量大,且主要分布于经济发达和人口密集区域,对环境和社会经济影响大,因此修复受损高速公路边坡见效快,且对总体目标贡献率高达50.24%;不同种及不同生活型的植物有效性差别很大,可有多种组合搭配模式,但针对目标群落应首选对修复类型最有效的植物作为绿化植物。【结论】拟以灌草型、乔灌草型和藤草型植物群落分别作为山区高速公路边坡、废弃矿山堆积坡和采石场石质边坡修复重建的目标植物群落。

植物根系对鄂尔多斯矿区排土场边坡产流产沙特征的影响

为探讨鄂尔多斯矿区排土场边坡不同植物根系对产流产沙特征的影响,采用原位放水冲刷试验研究不同植物根系(须根系、直根系、须根系—直根系混合)排土场边坡面的细沟侵蚀水动力学特征和产流产沙特征。结果表明:1)冲刷过程中不同植物根系小区的径流流速、阻力系数、径流剪切力和径流功率呈现不同的变化趋势,须根系和直根系均使坡面径流流速、径流剪切力和径流功率降低,须根系使阻力系数增大,直根系则相反。2)须根系小区的平均产流率最小;不同植物根系均使坡面产沙率降低,各小区平均产沙率减少51.28%~69.40%。3)根系有效降低土壤剥蚀率,须根系小区的最大减蚀率达71.1%。4)各小区临界径流剪切力和临界径流功率分别为0.04~1.28 N/(m·s)和0.02~0.25 Pa,2组临界值从大到小排序均为须根系小区、直根系—须根系混合小区、直根系小区和裸地小区。研究结果可为该区排土场边坡水土流失防治提供依据。

斜坡上混凝土多层框架结构隔震与装配式设计与难点分析

以7度区建于斜坡上的某重点设防类混凝土多层框架为例,对设计中同时采用隔震与装配式技术的结构设计进行了论述,对建筑周围地面有坡度时隔震沟的设置、隔震沟盖板顶标高不同时的建筑边缘和角部特殊节点构造、外绕柱式隔震沟节点构造、预制框架柱的选取、预制柱与建筑外墙保温节能一体化施工节点构造等难点进行了详细分析,可作为类似工程的参考。

穿坡油气管道的框架桩防护结构分析方法

针对沿山坡走向铺设的埋地油气管道存在的抗震防护问题,提出了一种新型的框架型抗滑桩式管道防护结构。在采用拟静力法确定作用于结构地震滑坡推力的基础上,将位于滑面以上的结构受荷段作为底端固定的平面框架结构,采用超静定平面刚架结构模型分析;而位于滑面以下的嵌固段则为埋置于稳定地层的两单桩结构,采用侧向受荷的弹性地基梁模型分析,由此建立了框架型抗滑桩的内力及位移计算方法。实例分析表明:框架桩前、后桩及上、下横梁弯矩与剪力的理论计算值与数值模拟结果误差均在±20%以内,理论结果偏于保守;水平地震影响系数对结构内力影响显著,结构内力最大值随水平地震影响系数增加近似呈线性增大,而竖向地震影响系数影响较弱;结构最大内力与土体重度呈线性正相关性,与黏聚力和内摩擦角呈非线性负相关性,且随着土体抗剪强度参数的增大,前、后桩以及上、下横梁的内力分别趋于接近;前、后排桩与上、下横梁的最大内力分别与桩体抗弯刚度呈非线性正相关性与负相关性,而分别与桩体嵌固深度近似呈线性正相关性与负相关性;框架桩间距对结构内力影响显著,而前后桩排间距则对结构内力影响较小。