Analysis of debris flow control effect and hazard assessment in Xinqiao Gully,Wenchuan M_(s)8.0 earthquake area based on numerical simulation

Xinqiao Gully is located in the area of the 2008 Wenchuan M_(s)8.0 earthquake in Sichuan province,China.Based on the investigation of the 2023"6-26"Xinqiao Gully debris flow event,this study assessed the effectiveness of the debris flow control project and evaluated the debris flow hazards.Through field investigation and numerical simulation methods,the indicators of flow intensity reduction rate and storage capacity fullness were proposed to quantify the effectiveness of the engineering measures in the debris flow event.The simulation results show that the debris flow control project reduced the flow intensity by41.05%to 64.61%.The storage capacity of the dam decreases gradually from upstream to the mouth of the gully,thus effectively intercepting and controlling the debris flow.By evaluating the debris flow of different recurrence intervals,further measures are recommended for managing debris flow events.

Dynamic simulation insights into friction weakening effect on rapid long-runout landslides:A case study of the Yigong landslide in the Tibetan Plateau,China

This study proposed a novel friction law dependent on velocity,displacement and normal stress for kinematic analysis of runout process of rapid landslides.The well-known Yigong landslide occurring in the Tibetan Plateau of China was employed as the case,and the derived dynamic friction formula was included into the numerical simulation based on Particle Flow Code.Results showed that the friction decreased quickly from 0.64(the peak)to 0.1(the stead value)during the 5s-period after the sliding initiation,which explained the behavior of rapid movement of the landslide.The monitored balls set at different sections of the mass showed similar variation characteritics regarding the velocity,namely evident increase at the initial phase of the movement,followed by a fluctuation phase and then a stopping one.The peak velocity was more than 100 m/s and most particles had low velocities at 300s after the landslide initiation.The spreading distance of the landslide was calculated at the two-dimension(profile)and three-dimension scale,respectively.Compared with the simulation result without considering friction weakening effect,our results indicated a max distance of about 10 km from the initial unstable position,which fit better with the actual situation.

Investigation and numerical simulation of summer sedimentation in Jiaozhou Bay, China

In recent years,development activities have had a significant impact on the environment of the Jiaozhou Bay,China.To ensure the sustainable economic and social development of the Jiaozhou Bay area,it is necessary to strengthen corresponding control measures.The important prerequisite is to properly understand the environmental conditions laws of natural change,especially the dynamic processes of sediment and the characteristics of landform evolution.Based on the data of continuous observation at 6 stations in Jiaozhou Bay for 25 hours,the Hydrodynamic Eutrophication Model(HEM-3D)was used to simulate the sediment erosion and deposition.The results show that the maximum suspended sediment concentration in the sea area of Jiaozhou Bay is about 40 mg/L,which appears in the northwestern area of the bay top and the Cangkou watercourse area,and the low concentration is located in the area of the central Jiaozhou Bay towards the bay mouth.The suspended sediment is 6?10 mg/L.Affected by a decrease in seawater material,the direction of the prevailing current in the Jiaozhou Bay area is different from that of the sediment transport.The velocity of the flood current is higher than that of the ebb current.However,during flood tide,the flux of resuspended seafloor sediment outside and at the mouth of the bay is limited and cannot contribute significantly to the suspended sediment in the bay.During ebb tide,the resuspended sediment at the shallow-water bay head and the east and west sides spreads toward the bay mouth with the ebb current,although it extends beyond the bay through the bay mouth.The research results can provide scientific support for the Jiaozhou Bay project construction and environmental protection.

Strength softening models of soil and its application in rainfall-induced landslide simulation

In this study, strength softening models are developed for exploring rainfall-induced landslide mechanism based on Mohr Coulomb strength theory with both saturation degree and temporal evolution into consideration. According to the ratio of two time scales available, the model can be classified into three categories, i.e., instant softening model, delay softening model, and coupling softening model. Corresponding evolution functions are specified to represent these kinds of softening processes and then applied to simulate landslide of homogeneous slopes triggered by rainfall, therefrom, useful conclusions can be drawn in the end.

Risk assessment of coastal flooding disaster by storm surge based on Elevation-Area method and hydrodynamic models:Taking Bohai Bay as an example

The future inundation by storm surge on coastal areas are currently ill-defined.With increasing global sealevel due to climate change,the coastal flooding by storm surge is more and more frequently,especially in coastal lowland with land subsidence.Therefore,the risk assessment of such inundation for these areas is of great significance for the sustainable socio-economic development.In this paper,the authors use Elevation-Area method and Regional Ocean Model System(ROMS)model to assess the risk of the inundation of Bohai Bay by storm surge.The simulation results of Elevation-Area method show that either a 50-year or 100-year storm surge can inundate coastal areas exceeding 8000 km^(2);the numerical simulation results based on hydrodynamics,considering ground friction and duration of the storm surge high water,show that a 50-year or 100-year storm surge can only inundate an area of over 2000 km^(2),which is far less than 8000 km^(2);while,when taking into account the land subsidence and sea level rise,the very inundation range will rapidly increase by 2050 and 2100.The storm surge will greatly impact the coastal area within about 10-30 km of the Bohai Bay,in where almost all major coastal projects are located.The prompt response to flood disaster due to storm surge is urgently needed,for which five suggestions have been proposed based on the geological background of Bohai Bay.This study may offer insight into the development of the response and adaptive plans for flooding disasters caused by storm surge.

Exploring mechanism of hidden,steep obliquely inclined bedding landslides using a 3DEC model:A case study of the Shanyang landslide in Shaanxi Province,China

Catastrophic geological disasters frequently occur on slopes with obliquely inclined bedding structures(also referred to as obliquely inclined bedding slopes),where the apparent dip sliding is not readily visible.This phenomenon has become a focal point in landslide research.Yet,there is a lack of studies on the failure modes and mechanisms of hidden,steep obliquely inclined bedding slopes.This study investigated the Shanyang landslide in Shaanxi Province,China.Using field investigations,laboratory tests of geotechnical parameters,and the 3DEC software,this study developed a numerical model of the landslide to analyze the failure process of such slopes.The findings indicate that the Shanyang landslide primarily crept along a weak interlayer under the action of gravity.The landslide,initially following a dip angle with the support of a stable inclined rock mass,shifted direction under the influence of argillization in the weak interlayer,moving towards the apparent dip angle.The slide resistance effect of the karstic dissolution zone was increasingly significant during this process,with lateral friction being the primary resistance force.A reduction in the lateral friction due to karstic dissolution made the apparent dip sliding characteristics of the Shanyang landslide more pronounced.Notably,deformations such as bending and uplift at the slope’s foot suggest that the main slide resistance shifts from lateral friction within the karstic dissolution zone to the slope foot’s resistance force,leading to the eventual buckling failure of the landslide.This study unveils a novel failure mode of apparent dip creep-buckling in the Shanyang landslide,highlighting the critical role of lateral friction from the karstic dissolution zone in its failure mechanism.These insights offer a valuable reference for mitigating risks and preventing disasters related to obliquely inclined bedding landslides.

碳酸盐岩缝洞型油藏注水井储量损失原因及治理对策——以塔河油田A区为例

注水替油为塔河油田缝洞型油藏稳产的重要方式之一,近年来,注水替油失效井占比逐年提升,注水井储量损失问题日益凸显。根据单井生产特征和地质特征,通过能量指示曲线、注水指示曲线定量化分析各阶段储量变化,动静态结合并融合数模、建模一体化技术,分析了储量损失的本质原因,并针对不同储量损失类型提出不同的治理对策,恢复失控储量,提高产能。储量损失主要分为远端储量损失和体内储量损失两大类,其中,针对远端储量损失以恢复远端供液为目标,针对体内储量损失以扩大井周动用为目标。实际治理效果与数模预测方案吻合,治理效果显著。

托普台南区块断溶体油藏栅状断片结构数值模拟

塔河油田托普台南区块断溶体油藏开发初期产量高,后期暴性水淹和快速见水井多,产量递减快,针对此类特征,目前尚未建立较好的模拟方法。结合断溶体油藏岩溶特征、地震特征、实钻井井储关系以及三带结构提出断溶体油藏栅状断片结构,根据此认识,通过融合断层自动提取技术和蚂蚁体属性,得到断裂指示因子,用以刻画栅状断片储集体,利用张量属性刻画溶蚀孔洞型储集体,建立双重介质组分模型,开展数值模拟研究。结果表明:栅状断片结构是断溶体油藏的主要导流通道;断裂指示因子比断层自动提取技术和最大似然更适合表征栅状断片结构,并在通水源处与张量属性匹配度高,在其他区域匹配性差;与单重介质模型相比,基于栅状断片结构的双重介质模型拟合精度更高,更能反映断溶体油藏生产动态特征。

火山岩气藏勘探开发理论技术与实践——以松南断陷白垩系火山岩为例

近20年来,中国石化东北油气分公司在松辽盆地南部的勘探进一步证明,盆地火山岩是寻找油气藏的新靶区,具有广阔的前景。东北油气分公司根据盆地勘探实践,总结了以主成藏期为关键点的“生烃灶-成藏期古构造-断盖保存-有效储层”联动演化的断陷层四元耦合控藏模式,推动了松南地区长岭断陷火石岭组大规模火山岩气藏的发现。火山岩勘探方向从营城组拓展到更深层的火石岭组,勘探目标从酸性火山岩拓展到中基性火山岩,从水上喷发到水下喷发。采用气藏精细描述技术,建模数模一体化及地质工程一体化技术,在松南断陷多口井取得产能突破,实现火山岩气藏高效开发和规模上产。

基于地质概化的坚硬厚基岩覆岩裂隙场演变特征研究

精准掌握采动覆岩导水裂隙带演化特征是防止工作面突水灾害发生的重要基础,尤其对于西部矿井高强开采条件尤为重要。以榆树湾煤矿201西翼盘区为背景,以各砂岩层单轴抗压强度、RQD、砂岩层厚度作为系统聚类分析指标提出了厚基岩地质概化方法,系统研究了不同基岩层厚度对导水裂隙带发育高度、裂隙角度、频次、节理应变能演变规律的影响,确定了导水裂隙带高度与节理总应变能的量化关系。研究结果表明:基于地质概化方法模拟所得导水裂隙带发育高度随基岩厚度增大呈现对数正相关增大趋势,且增加速率逐渐减小,该规律通过与邻近矿井实测结果对比分析,验证了其准确性;随着基岩厚度的增大,导水裂隙带内垂直裂隙发育频次显著增大,水平裂隙反之,这表明基岩厚度的增大对导水裂隙带内水平裂纹的萌生与扩展具有一定抑制作用;导水裂隙带发育高度与覆岩能量释放程度密切相关,随节理最大应变能和总应变能的增加呈指数增加特点,且增加速率逐渐增大。

正安地区页岩气三维地质建模及数值模拟应用浅析

本文以贵州正安地区A区块页岩气储层为研究对象,结合地震解释、钻井资料、测井数据等资料,运用petrel三维建模软件,建立正安地区A区块页岩气储层三维构造模型、三维地质力学模型及天然裂缝模型,对储层构造形态及天然裂缝的几何分布特点进行表征;在模型基础上,考虑应力阴影、天然裂缝分布特征、支撑剂沉降及运移,结合实际施工情况进行正安地区A区块人工裂缝扩展数值模拟并开展压后产能数值模拟研究,总体模型拟合率较高;该类页岩气藏模型的构建方法和实际应用,可为同类气藏的开发提供借鉴。

Runout prediction of potential landslides based on the multi-source data collaboration analysis on historical cases

Long runout landslides involve a massive amount of energy and can be extremely hazardous owing to their long movement distance,high mobility and strong destructive power.Numerical methods have been widely used to predict the landslide runout but a fundamental problem remained is how to determine the reliable numerical parameters.This study proposes a framework to predict the runout of potential landslides through multi-source data collaboration and numerical analysis of historical landslide events.Specifically,for the historical landslide cases,the landslide-induced seismic signal,geophysical surveys,and possible in-situ drone/phone videos(multi-source data collaboration)can validate the numerical results in terms of landslide dynamics and deposit features and help calibrate the numerical(rheological)parameters.Subsequently,the calibrated numerical parameters can be used to numerically predict the runout of potential landslides in the region with a similar geological setting to the recorded events.Application of the runout prediction approach to the 2020 Jiashanying landslide in Guizhou,China gives reasonable results in comparison to the field observations.The numerical parameters are determined from the multi-source data collaboration analysis of a historical case in the region(2019 Shuicheng landslide).The proposed framework for landslide runout prediction can be of great utility for landslide risk assessment and disaster reduction in mountainous regions worldwide.

浑源抽水蓄能电站泄洪排沙洞出口工程地质研究

浑源抽水蓄能电站泄洪排沙洞出口区围岩岩体单薄,发育有断层,隧洞施工难度大,风险高,运用工程地质分析原理与有限元数值模拟相结合的方法进行研究、分析,围岩类别为Ⅳ类,岩体较破碎,围岩不稳定,不同进洞点工程地质条件相同,边坡及隧洞开挖导致隧洞围岩塑性变化、位移、应力变化大小及规律基本相同,单纯变更进洞点位置的施工方案是不能降低隧洞施工难度的,也不能避免隧洞的施工风险。研究为泄洪排沙洞出口方案确定指明了方向。

基于ANSYS的浅层顺层岩质滑坡破坏模式分析——以大方县理化乡7.01滑坡为例

在判断浅层顺层岩质滑坡破坏模式时,往往受滑坡剪出口处人为工程切坡因素影响,对其牵引式或推移式难以确定,甚至判断错误。本文在收集滑坡区背景资料和滑坡地质灾害测绘的基础上,采用Auto-CAD软件,重建大方县理化7.01滑坡三维地质模型,利用有限元软件ANSYS Workbench的Static Structural模块,分别模拟滑坡发生前的岩土自重条件和1/2饱水条件下的岩土应力应变分布等值线。结果显示,应力集中于滑坡中后部,呈长条状分布,与发生滑坡前后地貌变形情况基本吻合,由此验证了模拟模型的有效性和可行性,判断了斜坡由中后部启动滑移,推移中下部岩土体,沿着灰岩顺层面形成推移式滑坡。本次模拟分析为今后识别类似地质灾害及判断其破坏模式提供参考,有助于指导类似地质灾害的防治。

大庆油田深层直井同井换热优化设计研究

为了有效开发利用油田深层的岩热型地热藏,提高地热能的开发效率,采用了直井井筒换热技术进行开发,通过地质建模与数值模拟方法,根据井身结构,对换热管柱型号、组合方式进行了优化,并调整注入水的入口温度和流量,以达到最佳的换热效果。实际结果表明,优化后地热能的开发效率得到了显著提高,达到了有效开发利用的目的,为同类型地热藏的开发利用提供了实际参考。这一研究成果对于提高地热资源利用率具有重要意义,也为相关领域的研究提供了有益的借鉴。

基于GMS的矿井涌水量预测

矿井涌水是矿山安全开采中难以解决又必须面对的问题。GMS(groundwater modeling system)具有强大的前、后处理功能,实现了地质模型、水文地质参数等的可视化,提供的自检功能为调试模型提供了极大方便。以宁夏某矿为例,应用GMS对其水文地质条件进行概化,建立水文地质结构模型和水文地质概化模型,通过MODFLOW模块对其涌水量进行预测。结果表明:三维地质模型具有很好地可视性,研究区地层能够更加直观的得以展示,模拟所得水位与实测水位拟合效果在置信区间内,模拟区首采面的涌水量的预测值为1450 m~3/h。为矿山开采、工程建设中涌水量预测的研究提供了更为直观、更为便捷的方法。

沉积数值模拟研究现状及实例

沉积数值模拟是开展沉积学定量研究的重要手段,在油气地质学、水利工程等领域中发挥着重要作用。本文基于大量国内外文献调研,结合实际研究工作,系统概述了沉积数值模拟的发展历程及模型分类;归纳了几何规则、水动力方程、扩散方程、元胞自动机和模糊逻辑5种沉积数值模拟方法;对比了不同方法的基本原理、优、缺点以及与其相对应的代表性模拟软件的特点;总结了沉积数值模拟在层序地层学,沉积过程及沉积机理,“源-汇”系统和油气地质学4个研究领域中的应用现状及独特优势;并结合东营凹陷北部陡坡带断层控制背景下两种湖相重力流沉积数值模拟研究实例,进一步说明了沉积数值模拟在沉积学研究中的有效性与重要性,探索不同沉积机制数值模拟新方法。多地质过程耦合数值模拟与地质建模一体化、基于人工智能驱动的沉积过程反演数值模拟以及在非常规油气资源勘探开发中的深入应用是该领域未来的发展方向。

河流相致密砂岩气藏剩余气精细表征及挖潜对策——以苏里格气田中区SSF井区为例

苏里格河流相致密砂岩气藏自投入开发以来,由于不同层位、不同位置地层压力的不均匀下降造成了储量动用不均衡,井间及层间存在大量剩余气资源。为提高气藏储量动用程度和天然气采收率,开展了精细储层构型表征、高精度三维地质建模和气藏数值模拟一体化研究,剖析了河流相致密砂岩储层剩余气形成机制及控制因素,建立了剩余气赋存模式,提出了针对性的挖潜对策。研究结果表明:(1)在单一辫流带/曲流带识别基础上,利用直井、定向井资料,定量刻画单砂体内部构型特征,研究区心滩平均宽度450 m,平均长度1040 m;点坝平均跨度950 m,平均宽度1100 m;落淤层平均宽度340 m,平均长度620 m,厚度0.2~0.8 m,倾角0.07°~0.37°;侧积层厚度0.2~0.8 m,倾角3°~7°。(2)分析了河流相致密砂岩储层中3类阻流单元及其对天然气渗流的阻流作用,并将研究区剩余气富集模式划分为:阻流型、井网未控制型、射孔未采出型、未射孔型4种。(3)针对阻流型剩余气采用重复压裂、钻加密井挖潜,针对井网未控制型采用老井侧钻、钻加密井挖潜,针对射孔未采出型采用气井精细化管理、排水采气挖潜,针对未射孔型采用查层补孔挖潜。(4)基于剩余气精细综合表征结果优化部署直井2口,水平井8口,完钻2口水平井测试地层压力平均为28.2 MPa,验证了井网未控制型剩余气的存在。结论认为,所提出的河流相致密砂岩气藏剩余气精细表征方法和挖潜对策,有助于提升气田天然气储量动用程度和采收率,为气藏的经济高效开发提供了技术支撑。

地下采矿引起地表塌陷离散元PFC^(2D)数值模拟研究

采用离散元PFC^(2D)建立了地质剖面颗粒流模型,研究了矿体开采过程中上覆岩层裂缝形成与发展过程,揭示上覆岩层逐渐垮塌崩落的机理。结果表明,随着矿体的开采,裂隙不断向上发展,裂隙数增加。开采矿体后形成的采空区造成了上覆岩层的拉裂⁃剪裂破坏,岩层中不断有新生裂缝产生。上覆岩层主要以拉裂缝发展为主,在拉裂缝发展区域两端产生部分剪破坏裂缝,在空区两端已经出现向上发展的裂缝集聚,是空区顶板逐渐垮塌崩落的征兆。开采第3分层和第4分层矿体后,出现了局部顶板垮塌现象,且垮塌崩落逐渐发展为整个采空区顶板垮塌,最终垮塌崩落至地表,在地表初步形成一个小塌陷坑。塌陷坑发展过程依据裂隙数可细分为平稳发展时期、缓慢发展时期、快速发展时期和结束发展时期,揭示了井下矿体开采致使上覆岩层拉裂⁃空区两端剪裂⁃整体垮塌崩落的形成机理。

深部硬岩巷道围岩变形特征及其控制技术

为探究深部硬岩巷道在复杂地质条件下的变形特性,本文以纱岭金矿-1465 m深部主巷为工程背景,通过现场工程地质调查获取了围岩的结构面信息,并计算岩体中的优势节理组和RQD值,对其地质环境和岩体条件进行概述。采用振弦式微应变传感器对调查点巷道的围岩进行监测,提取巷道顶板和两帮距离揭露面不同深度围岩随时间的变形数据,总结和分析深部硬岩巷道在高应力和复杂地质条件下围岩的变形特征。基于岩体条件和围岩变形规律提出该巷道宜采用“树脂锚杆+金属网+喷射混凝土”支护,并应用有限元数值模拟软件Phase 2对该支护方式进行有效性检验,结果表明,采用该支护方式可有效降低围岩的变形量。