On the probability of exceeding a given river flow threshold

ABSTRACT

To obtain estimates of the probability that a river flow will exceed a given threshold at time t + 1, given the flow value at time t, two stochastic models are considered: a filtered Poisson process and a diffusion process with jumps. Estimates derived from linear regression are also considered. The model parameters are assumed to depend on the flow value. An application to the Delaware River is presented.

Editor D. Koutsoyiannis; Associate editor S. Grimaldi     

煤矿底板突水防治研究进展与探讨

煤矿底板突水是矿井开发中一种严重的地质灾害现象,其受控于多因素影响且具有非常复杂的非线性动力特征。为了解决底板突水问题,从底板突水类型划分、煤矿水文地质条件综合研究、煤层底板突水预测预报方法、计算机成图技术及和数学方法及注浆堵水技术等方面系统总结煤矿底板突水的研究现状及存在问题,在此基础上从不同方面阐述了煤矿底板突水问题研究的发展前景和展望。     

禹登高速下伏铝土矿采空区注浆治理施工技术

对禹登高速公路下伏铝土矿采空区注浆治理施工中遇到的实际问题进行分析研究,采取有效的技术措施和组织措施,保证了采空区治理的效果。     

地下长距离废弃管道充填施工设计

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钢花管注浆加固在高速公路边坡挡墙病害防治中的应用研究

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Analyses of Seepage Problems in a Subsea Tunnel Considering Effects of Grouting and Lining Structure

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高压旋喷法在漂卵石冲洪积土软基处理中的应用

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地应力对油页岩地层劈裂注浆裂隙扩展的影响

地应力的差异性对劈裂注浆的裂缝扩展有着重要的影响。针对油页岩原位裂解区止水,本文提出定向射孔与劈裂注浆相结合的新方法,引导裂缝扩展。根据油页岩参数,利用RFPA软件,分析有无射孔对裂缝扩展的影响,并进一步分析地应力差异对有射孔时裂缝扩展的影响。结果表明,与无射孔注浆相比,有射孔注浆可定向劈裂并减小注浆压力;当x方向应力大于y方向应力时,射孔之间产生的大量裂缝将射孔连通形成帷幕;当x方向应力小于y方向应力时,随着应力差异的逐渐变大,裂缝扩展逐渐从x方向向y方向偏转,直到应力差异成为影响裂缝扩展的主要因素,射孔之间才未形成裂缝且不能连通。此研究成果可为油页岩原位裂解区止水工程提供借鉴。     

新密电厂翻车机室沉降处理设计及施工

针对新密电厂翻车机室的沉降,根据原地基处理情况,制定了压力注浆加固方案,通过试成孔确定了合理的施工设备及施工参数。针对砂砾石回填基础,采用套管跟进偏心钻头冲击钻进,很好地避免了钻进过程中的塌孔现象,保证了施工的顺利进行;间隔交叉注浆很好地保证了注浆效果。沉降观测结果显示,此次设计及施工方案是合理有效的,为类似工程的处理提供了较好的思路。     

Evaluation of liner responses due to non-uniform tail void grouting pressure

Tail void grouting initially does facilitate the action of ground loads around the lower half of the liner and no excess pressure being accumulated. However, at a later stage (almost at the completion of grouting), grout pressure becomes non-uniformly distributed around grout injection holes especially on the upper half of the liner. In the present study, the boundary and loading conditions were simulated by using a series of finite element analyses. It aimed to explore the effects of such temporary non-uniform loading conditions on development of the liner internal forces. The results obtained for tunnel with diameter of 6.0 m were presented. It was found that there were critical locations where application of non-uniform grouting pressure could result in large amounts of bending moment and deformation. Those critical locations; about ±30° to ±50° from crown of the tunnel, were about the locations where actual grouting was injected in the field. The stiffness of sub-soil beneath the tunnel invert had minor effect on the amount of induced structural forces. However, ground coverage was more important. The results, though cannot fully represent complicated tail grouting behaviours, provided a simple analytical procedure for exploring the effects of tail void grouting on the segmental liner.