A new anchor-siphon drainage combined method used for slope stabilization

A new anchor-siphon drainage combined method used for slope stabilization is proposed in this paper.It includes an anchoring section and a siphon drainage section.The novelty of the anchor-siphon drainage combined method is the realization of the drainage and anchoring in the one inclined borehole.The engineering cost of drilling and the resulting disturbance to the slope is reduced.To validate the feasibility of the proposed method,a numerical method that combines the pore water pressure distribution after siphon drainage and the anchoring force of the anchoring section is used to evaluate the safety of the slope with the anchor-siphon drainage method.The proposed method was illustrated and validated with the Hongpu Village landslide,in Tonglu County,Zhejiang Province,in China.Compared with the common anchor bar with the same length in the anchoring section,the factor of safety(FOS)for Hongpu Village slope with anchorsiphon drainage is increased by 0.085.The calculation method of the optimal length ratio between the drainage section and the anchoring section and its influencing factors were studied.For the different design parameters,there is always an optimal length ratio of the drainage section.Compared with the siphon drainage and full-length anchor bar with the same borehole length,the anchor-siphon drainage combined method shows better landslide prevention ability.Moreover,when the optimized parameters with a bond strength of 560kPa,a borehole inclination of 35°,and no reduction in length are used,the calculated safety factor is 1.316,which is significantly higher than the FOS of 1.131 for the slope with siphon drainage.

大型Petri网模型最小trap(siphon)集合的快速求解算法

为了快速确定大型Petri网模型中的trap(siphon)逻辑结构,提出一种由Petri网关联矩阵寻找最小trap和siphon集合的有效算法。通过分析Petri网中trap和siphon集合对应的库所子集在关联矩阵中的特征,根据变迁的输入输出库所组合规则和目的,提出一种二元操作算子,由此构造计算最小trap和siphon集合的矩阵求解算法,以实例详细阐述了算法的具体步骤。通过与已有求解方法的比较,进一步验证了该算法在求解大型Petri网系统最小trap(siphon)集合上的计算速度优势。

虹吸排水法处理软土地基的水位与沉降计算模型

软土具有渗透性差、承载力低等特性,软土地基的处理一直是岩土工程中的一大难题。利用虹吸免动力排水的特点,可将虹吸排水法应用于软土地基处理中,达到改善土体性质的目的。本文针对虹吸排水法独特的定降深降水模式,先基于离散化的Theis井流模型以及非线性的分层总和法,构建了以孔隙率为核心、渗透系数与压缩模量随固结情况改变的水位与沉降动态计算模型,并与数值模拟结果对比,然后从土体渗透系数、排水板间距以及场地大小3个方面对虹吸排水法处理软土地基的效果进行了分析。结果表明:数值模拟结果验证了计算模型的可靠性,对于浙江沿海不同渗透系数的土体,虹吸排水法均可起到良好的排水固结作用;调整排水板间距可对排水固结时间以及地下水位线起到显著控制作用;排水带来的附加应力随着场地面积的增大向土体深处延伸,对于面积50 m×50 m大小的场地,有效影响深度可达到地表以下27.31 m,远远超出虹吸扬程的极限。在实际的大面积软土地基处理中,虹吸排水法可发挥更好的作用。

核电厂虹吸井三维数值模拟研究

针对滨海核电厂的虹吸井排水泡沫问题,利用CFD计算软件基于VOF模型进行了数值模拟分析。对核电项目普遍采用的WES实用堰虹吸井内部流场进行了三维数值模拟,计算得到了不同水位下虹吸井内的气、液两相流的分布情况,分析了虹吸井内跌水和水跃掺气现象,为核电厂的虹吸井设计提供参考。

An improved siphon drainage method for slope stabilization

The siphon drainage is an effective measure for the slope groundwater control. However,for the traditional siphon drainage, limitations such as siphon lift restriction and poor reliability in longterm service prevent it from being widely used. In this study, an improved siphon drainage method with inclined borehole penetrating the deep part of the slope is proposed to overcome the limitations suffered by the traditional method. Through experimental research, theoretical analysis and engineering practice,the reliability and capability of the proposed method are investigated. The results demonstrate that with the inclined pipe the height difference between the control point of the groundwater level and the orifice can be controlled to be less than the height of the water column corresponding to the local atmospheric pressure. As a result, deep drainage can be achieved.In addition, by controlling the diameter of siphon drainage pipe not larger than 4 mm, a plug flow can be formed in the siphon pipe, which can prevent air accumulation in the siphon process and a continuous and effective siphon drainage is achieved. Through a practical project running smoothly since September 2013, it is found that the proposed method can effectively drain the groundwater deep in the slope and the maximum drawdown of groundwater level in boreholes can reach 8.5 m with an average drainage flow of 5.5 m3/d. The practical results also illustrate that 4 mm siphon pipe can be used to realize deep slope drainage and restart siphon automatically.

Development and Application of a Shaft-type Tubular Pumping System with a Siphon Discharge Passage

Based on the characteristics of large flow rate , low head , short annual operation time , and high reliability of the city flood-control pumping stations , a new-type shaft tubular pumping system featuring a shaft suction box and a siphon-type discharge passage with a vacuum breaker as the cutoff device was developed , which possesses such advantages as simple structure , reliable cutoff , and high energy performance.Taking some pumping stations as the case studies , in the light of the specified operation conditions , the hydraulic optimal design of the shaft-type tubular pumping system was determined and the optimized shape of the system was recommended.The performance prediction based on the computational fluid dynamics methodology was determined and the model test verification was conducted.The results show that the predicted data agree with the experimental head and efficiency so that both methods can be used to determine the performance of a real pumping station.Finally , the in-situ measurements of a pumping station during the commissioning period further verified that the shaft-type tubular pumping station with a siphon discharge passage is of higher efficiency , more reliable and stable.

Computation of an Emptiable Minimal Siphon in a Subclass of Petri Nets Using Mixed-Integer Programming

Deadlock resolution strategies based on siphon control are widely investigated.Their computational efficiency largely depends on siphon computation.Mixed-integer programming(MIP)can be utilized for the computation of an emptiable siphon in a Petri net(PN).Based on it,deadlock resolution strategies can be designed without requiring complete siphon enumeration that has exponential complexity.Due to this reason,various MIP methods are proposed for various subclasses of PNs.This work proposes an innovative MIP method to compute an emptiable minimal siphon(EMS)for a subclass of PNs named S^(4)PR.In particular,many particular structural characteristics of EMS in S4 PR are formalized as constraints,which greatly reduces the solution space.Experimental results show that the proposed MIP method has higher computational efficiency.Furthermore,the proposed method allows one to determine the liveness of an ordinary S^(4)PR.

Computation of Minimal Siphons in Petri Nets Using Problem Partitioning Approaches

A large amount of research has shown the vitality of siphon enumeration in the analysis and control of deadlocks in various resource-allocation systems modeled by Petri nets(PNs).In this paper,we propose an algorithm for the enumeration of minimal siphons in PN based on problem decomposition.The proposed algorithm is an improved version of the global partitioning minimal-siphon enumeration(GPMSE)proposed by Cordone et al.(2005)in IEEE Transactions on Systems,Man,and Cybernetics-Part A:Systems and Humans,which is widely used in the literature to compute minimal siphons.The experimental results show that the proposed algorithm consumes lower computational time and memory compared with GPMSE,which becomes more evident when the size of the handled net grows.

Siphon-Specific Expression of an Actin Encoding Gene Is Regulated by Six1/2 in Ciona savignyi

Actin is a ubiquitous protein and plays essential roles on cellular structure maintenance and cellular motility in both muscle and non-muscle tissues.Multiple genes encoding muscle actin have been identified from the ascidians,including those expressed in the larval tail muscle,the adult body-wall muscle,and adult heart muscle.In this study,a novel striated non-tail muscle actin gene was identified from the RNA-seq data of Ciona savignyi embryos.Phylogenetic analysis,alignment of the N-terminal amino acid sequences and comparation of diagnostic residues provided evidence that it had high similarity with vertebrate cardiac and skeletal muscle actin.In situ hybridization and promoter-driven GFP reporter assay revealed that it was specifically expressed in the primordia of the oral and atrial siphon.We hereby defined it as siphon-specific muscle actin coding gene(Cs-SMA).A 201 bp(−1350 bp to−1150 bp)sequence containing T-box and Six1/2 binding motif within the upstream region of Cs-SMA confined the expression of GFP in the siphons of electroporated embryos.Six1/2 binding motif was experimentally confirmed to play indispensable role in controlling the siphon-specific expression of Cs-SMA.The tissue-specific expression of Cs-SMA in the siphon primordia indicated its potential crucial roles in Ciona embryogenesis and organogenesis.

Investigation of a Flow Modulation System for Siphonic Roof Drainage Systems

Siphonic roof drainage systems (SRDS’s) have been widespread used now for approximately 40 years and are an efficient method of removing rainwater rapidly from roofs. SRDS’s are designed to run full-bore, resulting in sub-atmospheric system pressures with high hydraulic driving heads and higher system flow velocities than conventionally guttered systems. Hence, SRDS’s normally require far fewer downpipes, and the depressurised conditions also mean that much of the collection pipework can be routed at a high level, thus reducing the extent of any underground pipework. But, they work properly at only one roof run-off rate and therefore suffer from sizing and operational problems including noise and vibration which limit their performance and adoption rate. Climate change is creating situations where normal ranges of rainfall intensity are being frequently exceeded, so the typical:storm ratios (rTS) are large increasing. Current SRDS’s typically operate within a small rTS range of 2. This may have an impact on the future uptake of SRDS’s. This paper describes the development of a novel SRDS which includes a small mobile cap at the roof of outlet appears to offer benefits and avoids sizing problems associated with current SRDS’s. The cap has the potential to avoid noise associated with making and breaking siphonic action through flow modulation. Laboratory scale tests demonstrate the basic feasibility of the cap system and indicate that the cap functions reliably. This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Basic on sizing and design optimiza-tion factors are suggested. The rTS range is increased from approximately 2 to approximately 6.

Imageology of internal carotid artery siphon in nonarteritic anterior ischaemic optic neuropathy

AIM:To evaluate whether narrowing of internal carotid artery siphon(ICAS)may increase the risk of developing non-arteritic anterior ischaemic optic neuropathy(NAION).METHODS:Totally 30 consecutive patients who had unilateral NAION and 30 gender-matched control subjects were recruited in the present study.The diameter of ICAS of all the participants were measured using head-and-neck computed tomographic angiography(CTA).Color doppler flow imaging(CDI)was used to measure the haemodynamics parameters of ICAS and short posterior ciliary arteries(SPCAs)in all subjects.Comparison of parameters between the NAION patients and controls as well as between the two sides within the patients were performed.The correlation between the diameter of ICAS and NAION was analyzed.RESULTS:A comparison of parameters between the affected side of the NAION patients and the controls,including the diameter of ICAS,the resistance index(RI)of ICAS,the blood flow velocities of SPCAs and RI of SPCAs,showed significantly difference(P<0.01),while there was no significant difference in terms of the mean blood flow velocity(Vm)of ICAS;Similar results were found while comparing all the measurements of the affected and unaffected side of patients(P for RI of SPCAs<0.05).No marked difference was detected in nearly all parameters except for RI of ICAS and SPCAs between the unaffected side of the NAION patients and the controls(P<0.05).The diameter of ICAS were significantly positive correlated with both peak systolic velocity(PSV)of SPCAs and end diastolic velocity(EDV)of SPCAs in patients with NAION(r=0.514,P<0.01 and r=0.418,P<0.05,respectively).CONCLUSION:Narrowing of ICAS may increase the risk of developing NAION.

Elementary Siphons of Petri Nets and Deadlock Control in FMS

For responsiveness, in the Petri nets theory framework deadlock prevention policies based elementary siphons control are often utilized to deal with deadlocks caused by the sharing of resources in flexible manufacturing system (FMS) which is developing the theory of efficient strict minimal siphons of an S3PR. Analyzer of Petri net models and their P-invariant analysis, and deadlock control are presented as tools for modelling, efficiency structure analysis, control, and investigation of the FMSs when different policies can be implemented for the deadlock prevention. We are to show an effective deadlock prevention policy of a special class of Petri nets namely elementary siphons. As well, both structural analysis and reachability graph analysis and simulation are used for analysis and control of Petri nets. This work is successfully applied Petri nets to deadlock analysis using the concept of elementary siphons, for design of supervisors of some supervisory control problems of FMS and simulation of Petri net tool with MATLAB.

α-Siphons of a Suboptimal Control Model of a Subclass of Petri Nets

It has been a hot research topic to synthesize maximally permissive controllers with fewest monitors. So far, all maximally permissive control models for a well-known benchmark are generalized Petri net, which com-plicates the system. In addition, they all relied on time-consuming reachability analysis. Uzam and Zhou ap-ply First-met-bad-marking (FBM) method to the benchmark to achieve a near maximal permissive control policy with the advantage of no weighted control (WC) arcs. To improve the state of the art, it is interesting to synthesize optimal controller with as few weighted arcs as possible since it is unclear how to optimize the control for siphon involving WC arcs, This paper explores the condition to achieve optimal controller with-out WC and defining a new type of siphon, called α-siphon. If the condition is not met, one can apply the technique by Piroddi et al. to synthesize optimal controllers with WC.

Controllability of Strongly and Weakly Dependent Siphons under Disturbanceless Control

Li and Zhou propose to add monitors Vs to elementary siphons S only while controlling the rest of dependent siphons - important for large systems but far from being maximally permissive. The control policy for weakly dependent siphons (WDS) is rather conservative due to some negative terms in the controllability. We show that this is no longer true as can be shown that it has the same controllability as that for strongly dependent siphons.

双层立交结构连接井在引水、调水工程中的应用

我国水资源匮乏,且分布不均,为满足各地区经济发展需要及人民对生活环境改善的需求,各种引水、调水工程逐年增加。现浇钢筋混凝土箱涵是这类工程中应用较为广泛的一种输水形式。在分析传统多孔箱涵控制性构筑物(连接井)存在问题的基础上,以独流减河倒虹吸工程连接井设计为实例,引用立体交通概念,介绍了一种新的连接井设计形式。

滨海火/核电厂排水消泡技术综合分析

本文对滨海火/核电厂排水泡沫产生机理进行了分析研究。在总结分析工业废水以及现有电厂排水消泡措施经验和存在问题的基础上,提出了消除或大幅减少电厂排水泡沫环境影响的基本方法,对指导电厂排水虹吸井出流设计以及开展消能、消泡方法研究具有一定指导意义,同时也可为其他类似工业流程中的消泡设计提供参考。

虹吸管与辐射井相结合的尾矿坝排渗系统排渗效果分析

尾矿坝浸润面的位置直接影响坝体的稳定性。为快速有效地降低尾矿坝浸润面,提出了一种虹吸管与辐射井相结合的尾矿坝排渗系统,该系统利用自流式虹吸管代替排渗井中的抽水泵,以减少维护和运行费用、降低施工难度。进而以某尾矿坝工程为例,首先采用数学解析法计算了排渗井的渗透流量和虹吸管所需管径,初步确定了该系统的可行性;然后根据该工程尾矿料特性,建立了三维有限元渗流分析模型,利用子结构有限元法,对比分析了排渗井的排渗效果。结果表明,该排渗系统具有良好的排渗效果,并且虹吸管管径可满足工程施工要求。

沧州地区虹吸水平井开采浅层弱渗透微咸水技术研究

研究沧州地区虹吸水平井开采浅层弱渗透微咸水技术。在沧州地区成功施工一眼虹吸水平井,它巧妙地利用虹吸作用将浅部弱渗透地层中微咸水低能耗抽出。经长时间抽水试验得出:虹吸水平井水量足、开采成本低,可以作为新型供水水源用于农业灌溉;虹吸水平井长期抽取浅层微咸水水中含盐量逐渐降低,可以改良地下水质;虹吸水平井抽取浅层微咸水影响范围广,有利于大气降雨及地表淡水体的入渗及盐碱地的改良。

虹吸井和排水口泄流三维数值模拟及堰型优化

采用k-ε湍流模型封闭Reynods方程及VOF法追踪自由水面,对南迪普火电厂虹吸井和排水口的排水过程进行了三维数值模拟,其结果与模型试验结果吻合良好,表明三维数学模型用于虹吸井和排水口泄流模拟是可行的。在此基础上,针对原设计方案虹吸井溢流堰泄流偏于一侧、流速分布不均匀等缺点,分析了迷宫堰取代原方案折型堰后的流态,经三维数值模拟验证,迷宫堰堰上过流量及堰后流速分布基本均匀对称,是一种较为理想的堰型。

发电厂直流冷却水系统虹吸井布置方案设计和优化

虹吸井在发电厂直流冷却水系统中起着重要的作用,其设计方案的合理性对系统运行的安全性具有较大影响。在发生水力过渡过程的极端条件下,结合YH电厂的工程实例,分析了虹吸井布置方案对系统运行安全的影响,提出了布置方案的改进措施,总结了虹吸井布置方案设计的一般原则。