A study on seepage field in subgrade slope subjected to various rainfall patternsEI北大核心

Research purposes: Rainfall is one of the most important factors for subgrade slope failure, and rainfall patter is one of the most primary influence parameters. Based on the two-dimensional saturated-unsaturated seepage theory, numerical analyses are conducted to investigate the change rules of seepage field in subgrade slope subjected to rainfalls with four different patterns, i.e. delayed, uniform, central and advanced rainfall patterns. Research conclusions: (1) Both the maximum pore-water pressure umax and the maximum saturated depth Hsmax at shoulder are affected by rainfall intensity and rainfall duration observably. (2) There is a sensitive range of coefficient of permeability influencing on the maximum saturated depth, only within the sensitive range increasing coefficient of permeability could reduce Hsmax and subgrade surface pore-water pressure effectively. (3) Under central and advanced rainfall patterns, the most dangerous time stage of slope stability is obvious affected by coefficient of permeability, within the sensitive range and the less side outside the sensitive range, the starting point of the most dangerous time stage is not affected by coefficient of permeability, but the end time is advanced with coefficient of permeability increasing. (4) The stability of subgrade slope is the best under advanced rainfall pattern and the worst under delayed rainfall pattern. (5) The research results can provide basis and reference for slope protection and reinforcement design.     

富水软岩隧道施工中渗流对岩体变形影响的研究

以湖南省吉怀高速公路南山寨隧道为工程背景,建立流固耦合模型和普通对比模型,分别对考虑渗流场和不考虑渗流场的隧道开挖进行数值模拟与对比分析,以研究富水软岩隧道施工中渗流对岩体变形的影响态势和程度。     

隧道与地下工程防排水技术近年来的探索与改进

随着隧道、地铁等地下工程建设的迅速发展,防排水技术的发展也取得了令人瞩目的成就和进步。对当前地下工程混凝土结构防水和耐久性设计与施工、运营中的地下工程维护、检修以及相关病害的调查与治理等若干技术的应用及发展进行介绍与展望,以期针对显现的问题,从细节着手,进一步有效地优化防水及耐久性设计,改进施工工艺,提高工程防水质量,从而使地下工程防排水技术作为一个综合体系能得到进一步的完善和发展。     

限量排放下的隧道地下水渗流分析

以广东某在建高速公路隧道工程为例,通过地下水渗流计算分析,确定隧道富水段注浆后岩体渗透系数,最终实现地下水的限量排放。渗流计算采用连续介质模型,主要考虑泄水孔间距、隧道承压水头以及渗透系数的变化,分析孔隙水压力分布、地下水渗流路径,以及渗透系数与渗流量之间的关系,隧道富水段围岩注浆后,其渗透系数理论上不应超过2x10-5m／s控制指标的结论,可为隧道工程的安全施工提供较好的理论指导。     

Numerical evaluation of land subsidence induced by dewatering in deep foundation pit

To predict the behavior of land subsidence due to groundwater withdrawal, a 3D numerical model is established. The model takes the confined aquifer and soft deposit of Ningbo into account. According to the pumping test data, changing regulations of groundwater level, and land subsidence during dewatering are analyzed. Comparison between the calculated value and measured value shows that the 3D model simulates the measured value fairly well. The future behavior of land subsidence during dewatering period provides the scientific basis for the construction of deep foundation.     

渗井技术在高速公路排水工程中的应用

针对近几年来不少平原区高速公路项目中出现的"水淹地"、"水冲地"等排水不畅的问题,分析了平原区排水不畅的原因,指出了蒸发池、开挖排水沟等排水设施的弊端,并提出采用渗井技术来解决高速公路排水不畅的方案。     

橡胶粉改性沥青成套设备的研制

橡胶粉改性沥青生产设备的性能和作业工艺直接影响到改性沥青的路用性能优劣,基于JKXL15型橡胶沥青设备的研制,分析该类设备的结构设计要点和使用工艺的优化。     

地下水渗流对地基承载力的影响研究

地下水的定向流动会对土的骨架产生力的作用效果。借助经典土力学理论,对渗流作用下地基土的破坏模型进行修正,并由此推导出考虑地下水渗流作用时地基极限承载力公式。     

基于流-固耦合理论的病险土石坝渗流规律

土石坝病险问题主要是各种原因引起的渗漏。因此,研究病险土石坝加固技术首先必须分析土石坝渗流规律和渗透机理。基于多孔介质流-固耦合理论,在不考虑土体和水的压缩性以及孔隙率不变的假定下,利用FLAC3D数值分析软件,建立了土石坝二维模型,对2种病险土石坝模型的应力场、渗流场以及孔压进行了分析,总结得出了土石坝的渗流规律和土石坝渗漏机理,为土石坝加固技术提供了理论依据。     

地下结构抗浮设计讨论

近年来,大规模的地下空间开发使得抗浮设计越来越受到重视,其中抗浮措施的选择及浮力产生的机理是抗浮设计的关键。由于土体的复杂性,浮力产生的机理尚不明确,有待于进一步的研究。该文通过对浮力机理相关文献的评述,认为综合考虑不同含水层之间的渗流以最终确定浮力的计算原则是合理的。如此计算浮力更加准确,但需详尽的水力勘测资料。最后,以海八路隧道工程为例,确定抗浮措施并按照传统方法进行抗浮设计。