Study on the deformation and failure modes of filling slope in loess filling engineering: a case study at a loess mountain airport

Lvliang airport is a typical loess filling engineering located in 20.5 km north of Lvliang City in Shanxi Province, China. By the end of March 2012, 14 fissures extending more than 7.5 m were observed in a loess-filled slope, of which the longest fissure is up to 82 m. Field monitoring and laboratory tests have been performed to investigate the slope failure modes. The test program includes wetting tests on unsaturated compacted samples and stress path tests on saturated samples. Field monitoring and observations show that differential settlement caused by non-homogeneity in compacted loess density might lead to the formation of fissures in the loess-filled slope. It was founded that the wetting deformation contributed to the development of differential settlement. Fissures are the essential factor for the loess-filled slope failure. Four deformation stages exhibit in the loess-filled slope prior final failure including development of the fissures, softening of the compacted loess, creeping of the slope leading edge and fissuring of the trailing edge and formation of the through-sliding surface. Development of the sliding surface mainly includes upward and downward expansion of the fissures. Upward expansion is a wetting failure process in loading condition, while downward expansion is a load-off wetting process. In addition, development of the sliding surface is accelerated by softening of the compacted soils as a result of water infiltration. Therefore, the key for taking countermeasures against filling landslides is to monitor and control the development of differential settlement and fissures in the slope shoulders. Digging out and extra-filling the fissures are an effective way for preventing these landslides.     

基于土壤侵蚀遥感调查的河流输沙量的计算

河流泥沙来量的计算是工程水文计算的一个重要组成部分。有水文站观测资料的地方,输潲星的计算比较容易。而对于没有水文站分布或观测资料不足的边远地区,用常规无法计算出输沙星。     

Reservoir characteristics and main controlling factors of oil sand in Houba area,northwestern Sichuan Basin,China

Houba oil sand in frontier Longmenshan Mountain is one of the most typically important unconventional resources. The basic reservoir characteristics of oil sand and the main factors affecting reservoir quality were examined in this article based on porosity, permeability, and mercury porosimetry measurements; thin section analyses; SEM observation; and X-ray diffraction analysis. This study shows that the oil-bearing sandstone reservoir is mainly medium?coarse-grained sublitharenite and litharenite. The main pore type is intergranular pores, including residual primary intergranular pores, dissolved intergranular pores, and dissolved intragranular pores; fractures are common in this study area. The quality of sandstone reservoir is of high porosity and high permeability with a high oil saturation of 89.84 %. It is indicated that the main controlling factors of the reservoir in the study area include deposition, diagenesis, and tectonism. Deposition laid a foundation to porosity evolution, and channel sand is the most favorable depositional facies for the reservoir. Diagenetic alterations are the keys to reservoir evolution; dissolution and chlorite coatings cementation play an effective role in the generation and preservation of pores. Compaction, carbonate cementation, and quartz overgrowth cause many damages to the reservoir porosity. Fractures caused by structural breakages can improve the reservoir permeability and they also can provide fluid migration pathways to the late corrosion, which formed a lot of corroded fissures as reservoir and percolation spaces.     

宜章县梅田的晚二叠世地层不宜采用“泡水组”之名

泡水组系杨逢清、殷鸿福1987年新建的岩石地层名称,命名地点在广西来宾县泡水,层位与长兴组相当,时代属晚二叠世晚期。杨逢清,殷鸿福将泡水组引用到湖南宜章梅田长兴阶的地层。根据岩性特征,笔者认为宜章梅田长兴阶的地层不能冠用泡水组,只能沿用梅田组、九陂组和麻田组。     

塔里木盆地玉北地区奥陶系储层成因研究

玉北地区奥陶系碳酸盐岩经历了加里东期和海西期构造作用的改造,东部断褶带和西部斜坡区断层发育,中部平台区断层不发育,导致勘探目的层鹰山组上部与鹰山组下部和蓬莱坝组储层发育特征的不同。鹰山组上部的储层主要受控于加里东期构造活动所造成的地层抬升暴露剥蚀,形成了以大气淡水溶蚀为主的储集空间类型;而鹰山组下部和蓬莱坝组储层则主要受到埋藏白云石化作用、硅化作用以及伴随着断层的形成而发育的裂缝和热液的改造作用的控制。氧碳同位素和⁸⁷Sr/⁸⁶Sr比值的分布特征也进一步证明了两种不同储层类型的主控因素。鹰山组上部洞穴中方解石的氧碳同位素值（δ¹⁸O_VPDB：-12～-4‰VPDB,δ¹³C：-3～1‰VPDB）比海水沉淀的方解石（δ¹⁸O_VPDB：-9.5～-7.5‰VPDB,δ¹³C：-1.5～0.5‰VPDB）在数值上明显偏负,说明洞穴中充填的方解石属于淡水成因。在鹰山组下部和蓬莱坝组白云岩储层中发育的鞍形白云石具有较低的氧同位素值（δ¹⁸O_VPDB：-10.7～-5.9‰VPDB）和高于海水的⁸⁷Sr/⁸⁶Sr值（均大于0.7094）,因而被解释为热液成因,进一步说明这些地层中的溶蚀孔洞可能与热液改造有关。     

塔里木盆地巴楚—麦盖提地区石炭系混合沉积研究*

通过岩心、薄片观察,从岩石学特征入手,结合测井资料,对塔里木盆地巴楚—麦盖提地区石炭系的陆源碎屑—碳酸盐混积岩和混积层系进行了研究。根据混积强度将混积岩划分为混积型碎屑岩、混积型碳酸盐岩和高度混积岩。巴楚组下泥岩段和中泥岩段发育混积型碎屑岩,巴楚组生屑灰岩段、中泥岩段和小海子组发育混积型碳酸盐岩,卡拉沙依组上泥岩段、巴楚组下泥岩段及巴什托局部地区的中泥岩段发育高度混积岩。高度混积岩出现在海退期沉积的碎屑岩段,代表了陆源碎屑—碳酸盐强烈混合的过渡性沉积环境。研究区石炭系可识别出4个三级层序,混积层系主要发育在海侵体系域早期和高位体系域晚期,以间断混合和相缘混合为主。研究认为混积强度是评价混合沉积环境性质的主要参数,并将其划分为4级。下泥岩段存在混积强度达3级以上的混积界面,能用于地层对比。最后,结合混合沉积特征讨论了构造运动和海平面变化对研究区石炭系层序组以上的混合沉积的控制作用。     

塔中地区顺9井区柯坪塔格组黏土膜成因及其油气地质意义

为寻觅致密砂岩储层中发育的优质储层提供理论依据,分析铸体薄片鉴定、扫描电镜资料、结合压汞及物性资料.结果表明:塔里木盆地塔中顺9井区志留系柯坪塔格组沥青砂岩中发育的黏土矿物薄膜形成于成岩早期(同生成岩期),以自生式为主,含少量原生式黏土膜;黏土膜的发育与分布受到沉积作用、成岩环境及成岩温压系统的共同控制,早成岩期(同生期)发育的黏土膜在中—低压实强度下对储层的孔隙保护具有一定的建设性作用,因其占据一定的孔喉空间,又降低储层的渗透率,随着埋深增大,黏土膜矿物成分也逐渐向伊利石转化并分布在孔隙中,伊利石赋存状态也由蜂窝状变为毛发状、丝网状及搭桥状,分割甚至堵塞孔隙,使得储层砂体渗透率大幅度降低;沉积环境中的沉积微相对黏土膜发育与分布的控制体现在中—下临滨微相中黏土膜较为常见,而在上临滨—前临滨微相中,因水体的淘洗降低储层砂体中的泥质含量,黏土膜不发育,储层砂体中的黏土膜含量制约储层质量,发育黏土膜的井段储层孔隙度大于不发育黏土膜的井段,黏土膜含量在0.5%～5.0%井段的储层孔隙度要好于黏土膜含量超过5.0%井段的.     

鄂尔多斯盆地古生代中央古隆起形成演化与油气勘探

鄂尔多斯盆地古生代中央古隆起形成演化对该地区构造格局和油气勘探具有重要意义.通过对古生代构造背景、地层体残余厚度、奥陶系顶面构造演化等特征分析,刻画中央古隆起在不同沉积期构造演化特点,大体分为3个演化阶段:初始演化阶段:相对独立的中央古隆起形成于中晚寒武世:发育阶段:中央古隆起在早奥陶世马家沟期反映最为明显,为隆升剥蚀...     

海南岛泥盆纪地层研究进展

海南岛是否存在泥岔系?是该岛及华南地区长期悬而未决的重大基础地质问题之一。由于没有直接的古生物依据,以往多数研究者认为该地区不存在泥盆纪沉积。但亦有学者根据早石炭世早期化石的存在,推测其下伏地层可能为中—晚泥盆世。这一地质时期记录的长期不确定,极大地影响到对该岛和华南地区区域地质发展史和大地构造性质以及构造演化等问题的正确理解,也影响到冈瓦那大陆离散和亚洲大陆增生等地质理论的科学阐述。近年来,我们采获较丰富的牙形刺化石,从而肯定海南岛确实存在泥盆纪地层。标志着对这一疑难地层问题的研究取得了突破性进展。     

鄂尔多斯盆地北部下奥陶统储集岩的分类评价

本文以毛管压力测试得到的岩样微观孔隙结构特征参数作为分类评价的基本定量指标，采用Ｑ型聚类法将所测试的岩样分作了５个类别；结合每一类别的地质、物性及生产特点，将鄂尔多斯盆地北部下奥陶统储集岩分成五类，并分别对各类储集岩的储集性能作出评价。