DESIGN SLOPE牺牲阳极阴极保护设计方法

海洋工程领域常用的牺牲阳极阴极保护设计法可能存在过度设计的问题。针对此问题,文章介绍了适用于无涂层结构物的DESIGN SLOPE牺牲阳极阴极保护设计法。首先,简述了阴极保护下结构物表面生成钙镁沉积层的机理,分析了结构物表面极化特性在设计寿命期内的变化情况;然后,结合牺牲阳极阴极保护系统等效电路,引出DESIGN SLOPE的概念,说明该设计方法的基本理论;最后,应用DESIGN SLOPE设计法完成某平台牺牲阳极阴极保护设计工作。该法能够避免牺牲阳极阴极保护过度设计,从而提高设计方案的经济性。

A new slope optimization design based on limit curve method

A new method is proposed for slope optimization design based on the limit curve method, where the slope is in the limit equilibrium state when the limit slope curve determined by the slip-line field theory and the slope intersect at the toe of the slope. Compared with the strength reduction (SR) method, finite element limit analysis method, and the SR method based on Davis algorithm, the new method is suitable for determining the slope stability and limit slope angle (LSA). The optimal slope shape is determined based on a series of slope heights and LSA values, which increases the LSA by 2.45°-11.14° and reduces an invalid overburden amount of rocks by 9.15%, compared with the space mechanics theory. The proposed method gives the objective quantification index of instability criterion, and results in a significant engineering economy.

Optimum Design of Highway Excavation Slope Angle: Evidence from Dawu Section of Jingzhu Highway

The optimum design of the highway excavation slope angle is one of the most important problems to the highway construction and to the slope improvement. The Dawu Section of Jingzhu (Beijing Zhuhai) Highway is taken as an example to illustrate the study method for excavation slope angle design. The analysis of the engineering condition from different angles with different factors shows that the stability of the slope is calculated by using residual pushing force and the Sarma method. Then the sensitive analysis of the slope stability is conducted by using residual pushing force method. Finally, the optimum angle of design is presented on the precondition of ensuring the whole stability of slope and the economic reasonability. The study results show that the most sensitive factors are the shear strength parameter and the seismic force, and that the optimum excavation slope angle is 60°.

Comprehensive evaluation of high-steep slope stability and optimal high-steep slope design by 3D physical modeling

High-steep slope stability and its optimal excavation design in Shuichang open pit iron mine were analyzed based on a large 3D physical simulation technique. An optimal excavation scheme with a relatively steeper slope angle was successfully implemented at the northwest wall between Nos. 4 and 5 exploration lines of Shuichang Iron Mine, taking into account the 3D scale effect. The phys-ico-mechanical properties of rock materials were obtained by laboratory tests conducted on sample cores from exploration drilling directly from the iron mine. A porous rock-like composite material was formed for the model, and the mechanical parameters of the material were assessed experimentally;specifically, the effect of water on the sample was quantitatively determined. We adopted an experimental setup using stiff modular applied static loading to carry out a visual excavation of the slope at a random depth. The setup was equipped with acous-tic emission （AE） sensors, and the experiments were monitored by crack optical acquirement, ground penetrating radar, and close-field pho-togrammetry to investigate the mechanisms of rock-mass destabilization in the high-steep slope. For the complex study area, the model re-sults indicated a clear correlation between the model＇s destabilization resulting from slope excavation and the collected monitoring informa-tion. During the model simulation, the overall angle of the slope increased by 1-6 degrees in different sections. Dramatically, the modeled excavation scheme saved over 80 million tons of rock from extraction, generating enormous economic and ecological benefits.

A New Method of Construction of Robust Second Order Slope Rotatable Designs Using Pairwise Balanced Designs

The following article has been retracted due to the investigation of complaints received against it. Title: A New Method of Construction of Robust Second Order Slope Rotatable Designs Using Pairwise Balanced Designs. Authors: Bejjam Re. Victorbabu, Kottapalli Rajyalakshmi.The paper is a copy of Dr. Rabindra Nath Das’s former article, entitled “Slope rotatability with correlated errors (Vol. 54, pp. 57-70, 2003)” and “Robust second order rotatable designs (Part I)”. The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. This paper published in OJSVol.2 No.3, 319-327, 2012, has been removed from this site.

A comparative study of pseudo-static slope stability analysis using different design codes

Many researchers have developed new calculation methods to analyze seismic slope stability problems, but the conventional pseudo-static method is still widely used in engineering design due to its simplicity. Based on the Technical Code for Building Slope Engineering（GB 50330-2013） of China and the Guidelines for Evaluating and Mitigating Seismic Hazards in California（SP117）, a comparative study on the pseudo-static method was performed. The results indicate that the largest difference between these two design codes lies in determination of the seismic equivalence reduction factor( f;). The GB 50330-2013 code specifies a single value for f;of 0.25. In SP117, numerous factors,such as magnitude and distance, are considered in determining f;. Two case studies show that the types of slope stability status evaluated by SP117 are in agreement with those evaluated by the seismic time-history stability analysis and Newmark displacement analysis. The factors of safety evaluated by SP117 can be used in practice for safe design. However, the factors of safety evaluated by GB 50330-2013 are risky for slope seismic design.

Geotechnical Approach for Slope Design and Management Strategy for Nchanga Open Pit,Zambia

Rock slope stability is a very important research area for many geo-engineers concerned with civil or mining works.Slope stability of pits,roads,tailings dams and other embankments is very cardinal as it directly impacts on the working or utilization of these facilities.After a spate slope failures at the Nchanga Open Pits,a challenge arose to investigate the design parameters that have been in use.This research

Reliability Design for Longitudinal Slope Length of Expressway

The significance and the strategies of applying the reliability design method of longitudinal slope length in expressway engineering were explored in this study.The objective is to offer insights that can be beneficial for designing longitudinal slope lengths in contemporary expressway projects,with a focus on enhancing their reliability and safety.

滑坡治理方案的计算机辅助设计系统(Slope-CAD)的开发与研究

本文简要地介绍了“滑坡治理方案的计算机辅助设计系统 (Slope- CAD version 1.0 )”总体框架、基本思路、基本操作步骤以及其主要功能。滑坡治理方案的计算机辅助设计系统 (Slope- CAD)采用面向对象的程序设计语言和交互式图形处理技术开发。该系统具有交互式建立滑坡体地质模型、对滑坡体进行自动条分、自动采集各条块稳定性计算时所需参数以及智能化配筋等特点。利用 Slope- CAD,可以轻易地完成从滑坡体地质模型的建立→滑坡体稳定性计算→治理方案设计整个工作流程。通过对多个滑坡实例检验结果表明 ,Slope- CAD具有建模简单 ,操作方便 ,集成化程度高 ,自动化和智能化程度高 ,分析计算结果可靠 ,输出设计图纸方便快捷等优点 ,具有较大的推广应用价值。

公路边坡风险评估软件RASlope的研发与应用

模糊层次分析法在公路边坡风险评估中的运用日渐成熟,为规避该方法步骤多、计算繁杂等欠缺,提高评估效率,本文基于模糊层次分析法原理及步骤,基于MATLAB语言环境,通过需求分析、界面设计、代码编写、功能模块设计等流程研发出公路边坡风险评估软件RASlope。该软件遵循易用性、稳定性、高效性及可拓展性设计原则,由RASlope主界面、权重向量计算界面、隶属度分配界面及评估结果查看界面4个界面集成,可快速完成所有评估步骤,并提供对过程及结果数据另存、读取、分享功能。针对双永高速公路梨子岭隧道进口滑坡典型工程地质特征,设定4类12个风险评估指标体系,应用该软件进行快速风险评估,评估结果契合实际,合理地解释了滑坡诱发关键因素及工程治理的针对性和有效性,取得较好的应用效果,充分验证了该软件的应用价值。

Influence of rock property correlation on reliability analysis of rock slope stability: From property characterization to reliability analysis

Cohesion(c) and friction angle(φ) of rock are important parameters required for reliability analysis of rock slope stability. There is correlation between c and φ which affects results of reliability analysis of rock slope stability. However, the characterization of joint probability distribution of c and φ through which their correlation can be estimated requires a large amount of rock property data, which are often not available for most rock engineering projects. As a result, the correlation between c and φ is often ignored or simply assumed during reliability studies, which may lead to bias estimation of failure probability. In probabilistic rock slope stability analysis, the influence of ignoring or simply assuming the correlation of the rock strength parameters(i.e., c and φ) on the reliability of rock slopes has not been fully investigated. In this study, a Bayesian approach is developed to characterize the correlation between c and φ, and an expanded reliability-based design(RBD) approach is developed to assess the influence of correlation between c and φ on reliability of a rock slope. The Bayesian approach characterizes the sitespecific joint probability distribution of c and φ, and quantifies the correlation between c and φ using available limited data pairs of c and φ from a rock project. The expanded RBD approach uses the joint probability distribution of c and φ obtained through the Bayesian approach as inputs, to determine the reliability of a rock slope. The approach gives insight into the propagation of the correlation between c and φ through their joint probability into the reliability analysis, and their influence on the calculated reliability of the rock slope. The approaches may be applied in practice with little additional effort from a conventional analysis. The proposed approaches are illustrated using real c and φ data pairs obtained from laboratory tests of fractured rock at Forsmark, Sweden.

Probabilistic assessment of rock slopes stability using the response surface approach——A case study

This paper examines the stability condition of a jointed rock slope in the south western region of Saudi Arabia using deterministic and probabilistic approaches,under both dry and wet conditions.The study area is characterized by complex geology in rugged terrains.The stability analysis is carried out using the code FLAC3D to generate a 3-dimensional,ubiquitous joint model,to determine the influence of the dominant,unfavourable discontinuity orientation with respect to the slope face.The deterministic analysis is first implemented using the mean values of the selected random variables,namely the dip,dip direction and friction angle of the dominant discontinuity set,and the stability condition is assessed with a factor of safety based on the classical frictional joint constitutive model.A Box-Behnken design(BBD)approach is then adopted to create the surface response function as a second order polynomial for the factor of safety.To do so,fifteen FLAC3D models are generated in accordance with the BBD.Based on this,10,000 simulations of different slope realizations are carried out using Monte-Carlo simulation technique,and the probability of unsatisfactory of performance of the rock slope is assessed.It is shown that the probabilistic approach provides more insight and confidence in the stability condition of the rock slope,both under dry and steady state heavy rainfall conditions.A discussion is presented on the significance of accepting lower safety factors when heavy rainfall conditions are encountered.

Newly-simplified method for hydrauli design of micro-irrigation laterals based on emission uniformity

An analytical approach was developed to design a single uniformly sloping lateral in the micro-irrigation systems.Emission uniformity was used as the water application uniformity criterion.Energy relations based on the energy-gradient-line approach were revamped to account for the spatial variance of emitter outflow and the emitter connections local energy losses.Four pressure head grade line profiles were distinguished:uphill,horizontal,gentle downhill and steep downhill.Analytical expressions of emission uniformity by hydraulic variation for each pressure profile were developed based on the design variables:length and diameter of lateral,emitter spacing,emitter flow equation parameters,equivalent length characterizing local losses and ground slope.The design conditions for selecting emitter type,the number of emitters per plant and designing the diameter of the uphill and steep downhill laterals were also developed.The nonlinear equations for determining lateral diameter and lateral length were solved iteratively by using the built-in root-finding function of(Tools>Goal Seek…)in the calculation spreadsheet of Microsoft Excel.The procedures also provide the options to fix the design lateral diameter with the commercial standard size or fix the design lateral length based on the field size.The operating inlet pressure and maximum amplitude of the pressure head throughout the lateral could also be determined easily by the procedure.Two numerical applications with various slope combinations indicate that the proposed analytical approach produces results close to the accurate stepwise numerical solutions.In comparison with Keller method,the proposed approach could produce more appropriate designs.

Study on the Bioengineering Protection Technique for Rock Slopes in Railway

Ecological protection technique of rock slope is a new slope protection technique,and it is used widely in some supporting engineering of rock slope at railway and highway.But it is always an important research in the field of geotechnical engineering, because the study is related to many subjects and is not systemic and idiographic enough.The paper takes the rock slope of Luozhan(from Luoyang to Zhanjiang)

Overtopping Discharge of Wind-Waves on Simple Slope Dikes

An empirical formula for estimating the overtopping discharge of wind-waves on a smooth-impermeable-simple slope dyke is derived through model tests in this paper, it can be adopted by related design departments in the determination of the crest elevation of the dyke.

Dynamic response of a slope reinforced by double-row antisliding piles and pre-stressed anchor cables

Large-scale shaking table tests were conducted to study the dynamic response of a slope reinforced by double-row anti-sliding piles and prestressed anchor cables. The test results show that the reinforcement suppressed the acceleration amplification effectively. The axial force time histories are decomposed into a baseline part and a vibration part in this study. The baseline part of axial force well revealed the seismic slope stability, the peak vibration values of axial force of the anchor cables changed significantly in different area of the slope under seismic excitations. The peak lateral earth pressure acting on the back of the anti-sliding pile located at the slope toe was much larger than that acting on the back of the anti-sliding pile located at the slope waist. The test results indicate an obvious load sharing ratio difference between these two anti-slide piles, the load sharing ratio between the two anti-sliding piles located at the slope toe and the slope waist varied mainly in a range of 2-5. The anti-slide pile at the slope waist suppressed the horizontal displacement of the slope surface.

边坡支护工程设计和施工阶段关键技术分析

工程项目在进行建设过程中,不可避免地会出现开挖情况,对于地质较差的地方,为减小开挖工作量,常设置相关边坡防护措施进行及时防护。而边坡的防护形式和措施较多,其应用条件和经济性均不一致,若不进行相关现场分析和评估,盲目采用过大的防护,容易造成经济浪费,因此如何根据设计过程中的数据采用贴合的边坡防护是施工所希望达到的目的。本文以娄底市某边坡工程开挖为例,结合当地场地条件,分别从设计和施工角度对其在项目进行中的关键性技术进行分析,从而提出相关解决方案,达到经济适用性目的。最终结果证明,在施工完成后,该边坡情况良好。拟为相关类似工程提供参考。

建宁县某水厂边坡支护与排水设计

依托于建宁县某新建水厂边坡支护工程,采用动态设计法对场地的填方段边坡和挖方段边坡进行支护和排水设计,通过对安全性、施工难度、经济性、稳定性、效果等对比分析,最终选择挖方段边坡采用框架锚杆支护,而填方段边坡采用抗滑桩+锚索和挡土墙联合支护方案以及采用地表集水明排+坡体软式透水管或泄水管泄水的排水设计,采用极限平衡法验证了支护后的边坡稳定性。

巢湖市青苔山镁矿(冶镁白云岩)及冶金用白云岩矿矿山地质环境特征及治理建议

巢湖市青苔山镁矿(冶镁白云岩)及冶金用白云岩矿矿山生产造成地形地貌、生态景观破坏等一系列问题,急需进行生态修复工作。本文以现状调查为基础,以针对性解决矿山地质现状地质环境问题为重点,为矿山生态修复的治理提供更科学合理的治理设计方案。

长水机场隧道大坡度斜井反坡排水设计与施工技术研究

基于长水机场隧道,对其大坡度斜井反坡排水设计与施工进行了研究,根据现场抽排水需要,分阶段安装一级或多级泵站,以满足作业面排水。在1号、2号斜井开挖施工期间,采用集水坑接力抽排水方式;进入正洞后采用二级泵站抽排水,斜井中部缓坡位置水仓为二级泵站、正洞集水坑为一级泵站。斜井及正洞掌子面均设置临时集水坑及移动水箱。出口工作面施工段暗挖段里程为DK709+355~DK709+770,由大里程向小里程方向施工,顺坡排水,钻爆施工。实践证明,排水方案安全、合理、有效、可靠,没有因排水不及时或不能排水,对后续工程施工产生影响,提高了在大坡度斜井大流量反坡条件下隧道排水的施工水平。