Longitudinal vibration characteristics of a tapered pipe pile considering the vertical support of surrounding soil and construction disturbance

This research is concentrated on the longitudinal vibration of a tapered pipe pile considering the vertical support of the surrounding soil and construction disturbance.First,the pile-soil system is partitioned into finite segments in the vertical direction and the Voigt model is applied to simulate the vertical support of the surrounding soil acting on the pile segment.The surrounding soil is divided into finite ring-shaped zones in the radial direction to consider the construction disturbance.Then,the shear complex stiffness at the pile-soil interface is derived by solving the dynamic equilibrium equation for the soil from the outermost to innermost zone.The displacement impedance at the top of an arbitrary pile segment is obtained by solving the dynamic equilibrium equation for the pile and is combined with the vertical support of the surrounding soil to derive the displacement impedance at the bottom of the upper adjacent segment.Further,the displacement impedance at the pile head is obtained based on the impedance function transfer technique.Finally,the reliability of the proposed solution is verified,followed by a sensitivity analysis concerning the coupling effect of the pile parameters,construction disturbance and the vertical support of the surrounding soil on the displacement impedance of the pile.

Long Run Relationships, Vertical Integration and International Competition： Can They Contribute to Explaining Regional Construction Cost Differences？

The existence of opportunistic behavior by contractors or sub-contractors in the bidding process encouraged by the governance structure of construction companies as well as the kind of relationship that exist between contractors and clients is thought to have some bearing on the rising construction cost observed in some regions of Sweden. Three hypotheses that are intended to test the impact that long run relationship between contractors and developers, vertically integrated firms, and the increase of international competition could have on the construction cost increase levels were tested on a predetermined number of projects from six cities in different regions. The semi-structured survey produces inconclusive results. Long run and collaborative relationship was prevalent in small region though respondents in this region did not draw strong connection between construction cost increase levels and the kind of observed relationship. In Stockholm region, short-term relationship was mostly prevalent. Vertical integration and foreign competition impacts on construction costs were not significant in either region.

Construction of Vertical Wind Profile from Satellite-Derived Winds for Objective Analysis of Wind Field

During summer Monex-79, a variety of observing systems viz. research ships, research aircrafts, constant pressure balloons and geostationary satellite etc. were deployed, besides the regular conventional observations. The purpose of these additional systems was to make the best possible data for the studies on various aspects of monsoon circulation. The present study is aimed at the construction of vertical wind profile using cloud motion vectors obtained from GOES (I-O) satellite and to examine whether the constructed wind profiles improves the representation of the monsoon system, flow pattern etc. in the objective analysis. For this purpose, climatological normals of the wind field are considered as the initial guess and the objective analyses of the wind field are made with, first using only data from conventional observations over land areas, subsequently including the constructed winds from cloud motion vectors. These analyses are then compared with the standard analyses of wind field obtained from Quick Look Atlas by T. N. Krishnamurti et al. (1979).It is inferred that satellite estimated mean wind profiles show good agreement with the mean wind profiles of the research ships with RMS errors less than 5 mps below 500 hPa and less than 8 mps above 500 hPa. It is further inferred that the inclusion of constructed winds shows a positive impact on the objective analysis and improvement is seen to be more marked in the data-sparse region of the Arabian sea. Analyses which include the constructed winds show better agreement with the standard analysis, than the analyses obtained using only conventional winds. Thus, results of our study suggest that the wind profiles constructed using cloud motion vectors are of potential use in objective analysis to depict the major circulation features over the Indian region.

Activities of Urease and Phosphatase in Integrated Vertical Flow Constructed Wetland and Purification Effect of Black and Malodorous River

[Objective]The activities of urease and phosphatase in integrated vertical flow constructed wetland and purification effect of black and malodorous river were studied.[Method]Honeycomb stone and soft filler were used as matrix,the biological grid integrated vertical flow constructed wetland system was built to strengthen treatment for black and malodorous river,and the activities of urease and phosphatase of two fillers in different functional areas of constructed wetland were tested to study the film formation property of two fillers in different functional areas.[Result]Both urease and phosphatase activities on biofilm of soft filler were significantly higher than on biofilm of honeycomb stone filler;indicating that choosing soft filler was more advantageous to the growth of biofilm;and urease activity had significant correlation with total nitrogen removal rate,while phosphatase activity had no significant correlation with total phosphorus removal rate.[Conclusion]This study provided evidences for utilizing the activities of urease and phosphatase to evaluate the purification effect of black and malodorous river and choose appropriate filler.

Effects of Hydraulic Loading of Vertical Flow Constructed Wetland Clogging

[Objective] The aim was to al eviate the constructed wetland clogging problems and to explore to the effects of hydraulic loading on wetland clogging. [Method] The experiment, through artificial soil columns, simulated vertical flow arti-ficial wetland, set four hydraulic load level at 50, 100, 150 and 200 cm/d, to identify the impact of hydraulic loading on wetland clogging and to explore the factors run-ning threshold. [Result] The results show that the different levels of hydraulic loading have greater impact; in the constructed wetland clogging process under high hy-draulic loading of 200 cm/d, the effective life was only six months, and the single factor can be speculated that the threshold of the hydraulic load should be at 100-150 cm/d; system can last for six months at low hydraulic loading and last for three months at medium hydraulic load. [Conclusion] The research provides references for wetland clogging experiments in future.

Treatment and utilization of septic tank effluent using vertical-flow constructed wetlands and vegetable hydroponics

Vertical flow constructed wetlands is a typical ecological sanitation system for sewage treatment. The removal rates for COD, BOD 5, SS, TN, and TP were 60%, 80%, 74%, 49% and 79%, respectively, when septic tank effluent was treated by vertical flow filter. So the concentration of COD and BOD\-5 in the treated effluent could meet the quality standard for irrigation water. After that the treated effluent was used for hydroponic cultivation of water spinach and romaine lettuce, the removal efficiencies of the whole system for COD, BOD\-5, SS, TN and TP were 71 4%, 97 5%, 96 9%, 86 3%, and 87 4%, respectively. And it could meet the integrated wastewater discharge standard for secondary biological treatment plant. It was found that using treated effluent for hydroponic cultivation of vegetables could reduce the nitrate content in vegetables. The removal rates for total bacteria and coliform index by using vertical flow bed system with cinder substrate were 80%—90% and 85%—96%, respectively.

Application of High-efficient Vertical Flow Constructed Wetland in Treatment of Domestic Sewage in Residential Community

With the increase of requirement for ecological function of environment,for quality of water environment,for sewage treatment cost and for comprehensive utilization of water resources,it was bound to introduce a new type of ecological technology for pollution treatment which was low in cost,convenient in management and stable in operation.High-efficient vertical flow constructed wetland developed by Shenzhen Academy of Environmental Science was characterized by good landscape effect and high efficiency of pollutants removal,and it had been widely applied in sewa-ge treatment and recycling and in lake water circulation purification.A lot of practical results showed that this technology could achieve high removal efficiency of SS,COD,BOD5,NH4-N and TP and the removal rate had arrived at more than 80% when hydraulic loading was 0.33-0.50 m/d.Effluent quality had met the water quality standard for recycling of urban sewage.

Enhancing treatment efficiency of swine wastewater by effluent recirculation in vertical-flow constructed wetland

Livestock wastewater has been a major contributor to Chinese cultural eutrophication of surface waters. Constructed wetlands are under study as a best management practice to treat wastewater from dairy and swine operations, but the removal efficiency of pollutants is relatively low. Enhancing the treatment efficiency of livestock wastewater by effluent recirculation was investigated in a pilot-scale vertical-flow constructed wetland. The wetland system was composed of downflow and upflow stages, on which narrow-leaf Phragmites communis and common reed Phragraites Typhia are planted, respectively; each stage has a dimension of 4 m^2 （2 m × 2 m）. Wastewater from facultative pond was fed into the system intermittently at a flow rate of 0.4 m^3/d. Recirculation rates of 0, 25%, 50%, 100% and 150% were adopted to evaluate the effect of the recirculation rate on pollutants removal. It shows that with effluent recirculation the average removal efficiencies of NH4-N, biological oxygen demand （BOD5） and suspended solids（SS） obviously increase to 61.7%, 81.3%, and 77.1%, respectively, in comparison with the values of 35.6%, 50.2%, and 49.3% without effluent recirculation. But the improvement of TP removal is slight, only from 42.3% to 48.9%. The variations of NH4-N, dissolved oxygen（DO） and oxidation-reduction potential（ORP） of inflow and outflow reveal that the adoption of effluent recirculation is benefi- cial to the formation of oxide environment in wetland. The exponential relationships with excellent correlation coefficients （R2 〉0.93） are found between the removal rates of NH4-N and BOD5 and the recirculation rates. With recirculation the pH value of the outflow decreases as the alkalinity is consumed by gradually enhanced nitrification process. When recirculation rate is kept constant 100%, the ambient temperature appears to affect NH4-N removal, but does not have significant influence on BOD5 removal.

Significance of Primary Treatment Selection in the Efficiency of Wastewater Treatment in Constructed Wetlands (CWs)

This research explores strategies to enhance the efficiency of secondary treatment in Vertical Flow Constructed Wetlands (CW) in Montenegro. The focus is on selecting appropriate primary treatment methods alongside three distinct substrate types to improve wastewater treatment efficacy. The study examines the combination of two primary treatments with different substrate types in constructed wetlands (CW1, CW2, and CW3). The primary treatments include the existing wastewater treatment plant (WWTP) in Podgorica, involving coarse material removal through screens, inert material separation in aerated sand traps, and sediment and suspended matter removal in primary sedimentation tanks. The Extreme Separator (ExSep) was employed to evaluate its efficacy as a primary treatment method. The research demonstrates that the efficiency of CW can be significantly enhanced by selecting suitable primary treatment methods and substrates in Podgorica’s conditions. The most promising results were achieved by combining ExSep as a primary treatment with secondary treatment in CW-3. The removal efficiencies after CW3 for COD, BOD, and TSS exceeded 89%, 93%, and 91%, respectively. The outcomes underscore the significance of primary treatment in mitigating pollutant loads before discharge into the constructed wetlands, emphasizing potential areas for further optimization in wastewater treatment practices to enhance environmental sustainability and water quality management.

Effects of Cd^(2+) and Pb^(2+) on the substrate biofilms in the integrated vertical-flow constructed wetland

The effects of single Cd^(2+)and Pb^(2+),and combined Cd^(2+)and Pb^(2+)on dehydrogenase activity and polysaccharide content of the substrate biofilms in the integrated vertical-flow constructed wetland(IVCW)were studied.Dehydrogenase activities decreased linearly with the increasing concentrations of Cd^(2+)and Pb^(2+)at different times(6,24,72,and 120 h).The activities at both 6 and 24 h were significantly higher than that at 72 and 120 h in the case of single and combined treatments.The single Cd^(2+)and...

Phosphorus and Nitrogen Removal by Saturated Vertical-Flow Constructed Wetlands (SVCWs) Type Micro-Pilot Using Shale from Ivory Coast as a Substrate

This study evaluates the performance of shale from Ivory Coast used as substrate in vertical-flow constructed wetlands in removal of phosphates and nitrogen. The pilot-scale artificial wetland has been duplicated: filter planted with Panicum maximun and unplanted. They were set up outdoors, and fed with a municipal wastewater. The wetlands have been fed with three batches per week (intermittent) over a period of 3 months. During the operation period, the hydraulic residence time (HRT) 52 h was used, while wastewater temperatures varied from about ~33°C. The removal performance of the constructed wetland units was very good, since it reached on an average 98%, 89.4%, 89.4%, 84%, 80%, 84.8% and 92% for TSS, DOC, BOD5, , TKN, TP and respectively. In addition, the vegetation did not demonstrate superior performance to unplanted controls. Therefore, this study focuses on the role of shale in the phosphorus and nitrogen removal from wastewater by constructed wetland.

Significance of Substrate Selection in the Efficiency of Wastewater Treatment in Constructed Wetlands (CWs)

Constructed wetlands (CWs) can achieve a high-quality wastewater treatment and a quality that meets the prescribed standard, defined by legislation on wastewater discharge. A limitation in the application of constructed wetlands (CWs) is the large area requirement, which limits their application. The subject matter of this research is to check the possibility of improving the efficiency of wastewater treatment and reducing the required area for constructed wetlands (CWs) by using an adequate substrate under the conditions found in Montenegro. In the described experiment, the constructed wetlands (CW) have a vertical flow system and play the role of a secondary wastewater treatment, receiving water from the existing WWTP in Podgorica after the primary treatment. These vertical flow systems reflect experience with the use of similar systems in Slovenija, Austria and Italy. Measurements to date show that the substrate plays an important role and that wastewater treatment efficacy varies significantly with respect to the type of substrate when used under the conditions available in Montenegro.

“两纵一横”科技创新培养模式培育大学生核心素养的实践探索

通过创建“两纵一横”模式即以纵向科技项目立项和横向科技竞赛、大学生科技活动节和科技沙龙为激励,以双师双能型教师为保障,以双创能力为培养目标的新模式。提出构建“三个体系”和搭建“两个平台”模式,鼓励学生参与国家级和省市级别的纵向项目科技立项和开发与参加国家级、省市级横向科技竞赛相结合的方式,来实现大学生科技创新能力的提升和创新精神的培养。此外,通过建立“三库+三制度”保障体系,坚持以赛促学、以赛促教和以赛促改,实现赛教全方位融合,形成师生优势互补的新态势,培养一大批实践能力强、理论知识广的应用技能型工程师,最终实现应用型本科院校培养模式从“学历提升型人才”向“职业技能型工程师”的转变。该成果在校内和校外三年来的推广与应用证明“两纵一横”创新培养模式具有可操作性和可复制性,在应用型大学建设过程中取得显著效果,发挥引领示范作用。

超高层建筑施工过程竖向变形差控制技术研究

随着超高层建筑的不断发展,超高层建筑尤其是混凝土核心筒-外框钢结构超高层在施工过程中的竖向变形产生的相关问题引起各方关注。超高层建筑施工过程中的竖向变形差控制是难点之一,若处理不当,会影响施工安装、引起结构附加内力等问题。首先对超高层建筑竖向变形差的概念进行阐述,并进行了超高层建筑施工过程中竖向变形的理论推导。之后,对超高层结构施工过程竖向变形有限元分析方法进行介绍。在此基础上,对控制超高层建筑竖向变形差的措施进行分类,并对典型工程施工过程竖向变形控制进行分析,提出经济合理的控制方法。

垂直潜流人工湿地净化水中镉、氮、磷效果及机理

矿山区域因降雨形成含镉(Cd)、氮(N)和磷(P)混合废水,对生态和人类构成威胁,本文探求一种高效人工湿地净化装置并进行机理研究。设置“生物炭(BC)+土壤+菖蒲”试验装置(CWSPB),选择“土壤+菖蒲”(CWSP)与“BC+土壤”(CWSB)装置对照。结果表明,CWSPB对Cd、NH_(4)^(+)-N和TP去除效果最好,平均去除率分别为98.65%±1.90%、72.77%±19.35%和74.46%±16.06%。CaCl_(2)和Tessier提取法表明CWSPB土壤中Cd稳定性最好。FTIR和XPS分析表明,BC表面官能团-COOH、-OH和-C=O以及离子HPO_(4)^(2-)、PO_(4)^(3-)、OH^(-)、CO_(3)^(2-)参与Cd去除。微生物群落分析表明门水平细菌变形菌、拟杆菌、厚壁菌和真菌担子菌、毛霉菌及属水平细菌普雷沃氏菌、不动杆菌和真菌青霉菌、曲霉菌、木霉菌、紫球菌相对丰度增加明显。研究显示由BC、土壤和菖蒲组成的人工湿地在处理Cd、N、P废水有较好效果与潜力。

生物转盘耦合垂直流人工湿地对生活污水的净化效果及其微生物群落结构特征

为提高垂直流人工湿地对农村生活污水的净化效率,构建生物转盘耦合垂直流人工湿地系统。以实际生活污水为对象,研究耦合系统对生活污水的净化效果,并采用高通量测序分析其微生物群落结构特征,揭示微生物群落结构与污染物处理效率之间的关系。结果表明:系统对化学需氧量(COD)、氨氮(NH_(4)^(+)-N)和总磷(TP)的去除率分别为64.97%、86.84%和79.18%,出水平均质量浓度分别为71.70、3.21和0.67 mg·L^(-1);新型湿地系统适于处理COD、ρ(NH_(4)^(+)-N)和ρ(TP)分别为<250、30~50和<2 mg·L^(-1)的生活污水,且24 h为系统最佳运行时间;2个系统中不同填料区微生物种类无较大差别,相对丰度差别较大,共有的优势菌门、优势菌纲和优势菌目分别有5、8和10类,系统中除氮微生物主要为氢噬胞菌属(Hydrogenophaga)、假单胞菌属(Pseudomonas)等,除磷功能微生物主要有假单胞菌属、脱氯单胞菌(Dechloromonas)、不动杆菌属(Acinetobacter)、红球菌属(Rhodococcus)等;细菌群落影响污染物的去除,NH_(4)^(+)-N、TP和COD去除率与变形菌门和蓝细菌门呈显著正相关,TP浓度与绿弯菌门、COD与绿菌门呈显著正相关(P<0.05);各污染物主要在火山石区、沸石区被去除。研究结果明确了生物转盘耦合垂直流人工湿地微生物群落结构特征及其与污染物去除之间的关系,可为进一步提高人工湿地的处理效率提供科学参考。

煤矿矿井建设技术与装备70余年创新发展及推广实践

比较全面地总结了新中国成立70余年来,我国煤矿矿井建设技术从引进吸收、自主发展到再创新的历程,以及在基础研究、工艺创新、技术突破、装备研制和成果转化方面取得的重要成果,涉及钻爆法、冻结法、注浆法、钻井法、沉井法等凿井技术以及煤矿岩巷掘进技术。目前,以钻爆破岩为主的凿井配套装备机械化、自动化水平显著提高,煤矿千米级深井短段掘砌综合凿井技术趋于成熟,竖井凿井最大深度达到1 341.6 m。冻结法、注浆法等凿井地质保障技术水平显著提升,逐步代替了帷幕法、板桩法和降水法等凿井技术,竖井最大冻结深度达990 m,斜井最大冻结段斜长达681 m,采用工作面注浆建成煤矿最长斜井为5 875 m,竖井地面预注浆加固深度达1 355 m。机械破岩井巷掘进技术取得突破性进展,反井钻机最大钻井直径达6 m,最大钻井深度达562 m;竖井钻机钻井法实现了最大钻井直径10.8 m,最大钻井深度660 m,且应用范围逐步扩大;竖井掘进机钻井法实现了零的突破,为煤矿竖井智能化凿井奠定了基础;煤矿岩巷机掘法作业线已经形成,岩巷全断面掘进机平均成巷速度超400 m/月。综上,70余年来我国煤矿矿井建设技术与装备创新发展,显著提升了煤矿井巷掘进作业环境、施工效率和安全水平,实现了井巷掘进工作面无人化、自动化、全机械化作业,解决了我国煤炭开发各阶段井巷建设的难题,保障了煤矿基础建设及开采接续建设。同时,从煤矿矿井建设发展起来的技术装备和取得的成功经验,在水力发电、市政轨道交通、山岭交通隧道、引水隧道等地下工程领域得到了推广实践,为国家重点工程建设和国民经济发展做出了贡献。

BIM技术在1000MW大型火力发电工程中的应用

随着我国电力建设技术的快速发展,目前1000MW机组工程成为了主流,为保证工程顺利施工,需要借助数字化手段,赋能过程管理。本文介绍了将BIM技术应用于火力发电项目建设过程,辅助进行方案交底,特别是解决重大技术方案不直观、交底不透彻的问题,提升技术交底质量,从而减少返工和成本,产生良好的经济效益。重点介绍一种采用井字架吊具转换吊装高加设备的方法,在吊装施工前进行施工模拟重点技术工艺分析,开展建模内容分析和建模软件选择,进而建模和开展施工模拟,并以其中3个具有代表性的技术工艺模拟优化过程为例,阐述了BIM技术在项目立式高加安装中的应用。通过经济性分析,该施工方案经济效益明显,证明BIM技术的三维化、优化性、模拟性等优点,对于保障危重大施工方案的安全、顺利实施可以发挥十分重要的作用。

反井钻井技术在硬岩条件下矿山竖向开拓中的应用

该文以印度竖井工程建设为工程背景,分析硬岩地质条件下反井钻井的施工工艺、施工方案、故障分析及应对措施,结合近30条不同功能的反井施工经验,总结反井钻井技术在硬岩条件下竖向开拓中的应用效果。在矿山竖向开拓中采用反井钻井技术,能够减少工程成本,改善施工条件,提高施工效率,可以为类似工程施工提供参考。