Two-dimensional landslide dynamic simulation based on a velocity-weakening friction law

Surprisingly, hypermobility (high velocity and long run-out) is a remarkable feature of large landslides and is still poorly understood. In this paper, a velocity-weakening friction law is incorporated into a depth-averaged landslide model for explaining the higher mobility mechanism of landslides. In order to improve the precision of the calculation, a coupled numerical method based on the finite volume method is proposed to solve the model equations. Finally, several numerical tests are performed to verify the stability of the algorithm and reliability of the model. The comparison between numerical results and experimental data indicates that the presented model can predict the movement of landslide accurately. Considering the effect of velocity-weakening friction law, the presented model can better reflect the hypermobility of landslide than the conventional Mohr–Coulomb friction model. This work shows that the application of a universal velocity-weakening friction law is effective in describing the hypermobility of landslide and predicting the extent of landslides.     

The August 27, 2014, rock avalanche and related impulse water waves in Fuquan,Guizhou, China

At about 8:30 p.m. on 27 August 2014, a catastrophic rock avalanche suddenly occurred in Fuquan, Yunnan, southwestern China. This landslide and related impulse water waves destroyed two villages and killed 23 persons. The impulse waves occurred after initiation of the landslide, caused by the main part of the slide mass rapidly plunging into a water-filled quarry below the source area. The wave, comprising muddy water and rock debris, impacted the opposite slope of the quarry on the western side of the runout path and washed away three homes in Xinwan village. Part of the displaced material traveled a horizontal distance of about 40 m from its source and destroyed the village of Xiaoba. To provide information for potential landslide hazard zonation in this area, a combined landslide–wave simulation was undertaken. A dynamic landslide analysis (DAN-W) model is used to simulate the landslide propagation before entering the quarry, while Fluent (Ansys Inc., USA) is used to simulate the impulse wave generation and propagation. Output data from the DAN-W simulation are used as input parameters for wave modeling, and there is good agreement between the observed and simulated results of the landslide propagation. Notably, the locations affected by recordable waves according to the simulation correspond to those recorded by field investigation.     

全球气候变化背景下深圳海域海洋环境响应及对策

全球气候变化对人类社会和经济建设产生了广泛而深刻的影响。伴随着近期明显的全球气候变化趋势,在过去30年的短暂时间里,沿海城市深圳从一个小渔村迅速发展成中国的第四大城市,也由此伴生出现了诸多海洋相关的环境和经济问题。文章对全球气候变化以及人类活动影响下深圳周边海域的气候与环境的变迁及其风险进行了探讨,并提出了相应的对策,包括建设海洋观测网络、宣传教育、将气候变化纳入环境评估体系、主动干预等。海洋环境的可持续性是保障深圳市经济健康发展的关键条件之一,相关的结论也为全球关键城市气候变化的风险评估和管理提供了借鉴。     

硫酸镁对仿刺参幼参麻醉效果的研究

本研究以硫酸镁作为麻醉剂,比较了在不同水温条件下硫酸镁对仿刺参幼参的麻醉效果,分析了不同浓度硫酸镁对仿刺参幼参的麻醉效果。实验水温设置11℃、13℃、15℃、17℃、19℃和21℃六个温度梯度,实验用仿刺参幼参规格分为大规格(L)40.26±1.84g、中规格(M)21.83±1.72g、小规格(S)11.03±1.63g。实验结果显示:1.在硫酸镁麻醉剂浓度相同时,仿刺参规格越大麻醉所需时间越长,复苏时间却越短;随着麻醉剂浓度增加,对仿刺参幼参麻醉时间相应缩短,但复苏时间呈现逐渐延长。不同浓度硫酸镁麻醉剂对不同规格仿刺参的麻醉效果具有显著差异(P0.05)。2.在水温11℃~20℃范围内,随着水温的升高,对仿刺参幼参的麻醉时间从26.13±17.78min缩短到21.47±3.52min,但复苏时间从26.13±17.78min增加到71.05±12.32min,不同水温条件下硫酸镁对仿刺参幼参麻醉效果影响显著(P0.05)。研究表明,仿刺参体重在20g以下的适宜麻醉浓度为0.1~0.25mol·L-1,体重在20g以上的适宜麻醉浓度为0.25~0.35mol·L~(-1)。     

基于动态极值理论和Copula函数的极端海平面高度预测建模

全球气候变化背景下,海平面上升是一个潜在的重大风险,为防范气候灾害,应对极端气象海洋事件,需客观、定量地对未来极端海平面变化进行科学预测。为此,基于Copula函数和动态极值分析理论,综合考虑平均海平面变化(包括垂直陆地运动和基准的局地变化)与潮、涌、浪等其他气候变化的增水对极端海平面高度的影响,采用DREAM方法改进Bayes推断对动态极值模型的参数空间估计问题,提出一种新的模型对未来极端海平面高度变化进行预测,旨在改进传统模型存在的不确定性问题,并运用该模型对气候变化背景下厦门地区未来35年的海平面变化情景进行了模型应用和实验模拟。     

Snow disaster characteristics in Palongzangbu River Basin and mitigation countermeasures for road engineering

The Palongzangbu River Basin contains the highest number of maritime province glaciers in China.There are 130 glacial lakes,64 snow avalanche sites and 28 glacial debris flow gullies distributed within the basin.Snow disasters play a controlling role in the Sichuan-Tibet Highway construction,due to the terrain's special characteristics of high altitude and large height differential.Segmentation mitigation countermeasures for the Sichuan-Tibet Highway are presented based on snow disaster severity level and damage mode of the road.In the Ranwu to Midui section,snow avalanches are regional disasters, so the line should be placed in sunny slopes.In the Midui Gully to Yupu section,the line should be placed in shady slopes and at higher elevations to reduce the risk of glacial lake outburst.In the Yupu to Guxiang section,all three snow disasters are minimal.In the Guxiang to Tongmai section,glacier debris flows are the major threat,thus the road should be placed in shady slopes.     

Experimental study of motion characteristics of rock slopes with weak intercalation under seismic excitation

In order to investigate the effect of a weak intercalation on slope stability, a large-scale shaking table model test was conducted to study the dynamic response of rock slope models with weak intercalation. The dynamic response of the prototype slopes were studied in laboratory with the consideration of law of similitude. The initiation failure was observed in the rock slope model with a counter-tilt thin-weak intercalation firstly, not in the slope model with a horizontal thin-weak intercalation. Furthermore, it was interesting that the fracture site is shifted from crest top to the slope surface near the weak intercalation, which is different with the location of failure position in a normal layered slope. We also discussed the effect of the dip angle and the thickness of weak intercalation on the failure mechanism and instability mode of the layered rock slope. From the experimental result, it was noted that the stability of the slope with a counter-tilt weak intercalation could be worse than that of the other slopes under seismic excitation. The findings showed the difference of failure in slopes with a horizontal and counter weak intercalation, and implicated the further evaluation of failure of layered slopes caused by seismic loads.     

山东海阳姜家白垩纪水南组化石的发现及保护

姜家位于山东省烟台海阳市北部。在进行烟台地区古生物化石调查的过程中,发现了姜家这一白垩纪水南组良好的露头剖面,在其页岩中赋存丰富的动植物化石,计有玉门延吉叶肢介、长壳延吉叶肢介、中华狼鳍鱼、松柏纲和银杏纲植物化石及昆虫化石。根据前人化石保护评价方法,结合化石的赋存层位、赋存条件、化石类型及保护现状,计算了海阳姜家质量综合指数,认为其属于重点保护区级别;最后根据当地自然情况及工程影响,圈定了保护区范围,并制定了相应的保护措施。     

招平断裂带留仙庄空白区成矿远景预测

留仙庄空白区位于招(远)-平(度)断裂带中南段,道北庄子金矿东侧。招平带中南段已发现大、中型金矿3处,由南向北依次为夏甸、姜家窑、道北庄子金矿。通过收集分析已知金矿床最新矿床地质特征及成矿规律,总结招平断裂带中南段矿体控矿围岩、控矿构造、矿体赋存的基本规律,对留仙庄空白区进行远景预测,认为该区找矿潜力巨大。