长江Ⅰ级阶地某深基坑地下水控制分析

对于地处长江I级阶地的深基坑工程而言,由于其地层软弱、水文地质条件复杂、周边建筑密集等原因,地下水的有效控制成为基坑开挖成败的关键。本文以位于湖北荆州市繁华中心城区的地下商业城某深基坑工程为例,通过理论分析和经验判断,提出采用竖向隔水帷幕+深井降水的综合方案来控制深基坑地下水问题,即在弱透水层的潜水和承压水采用在支护桩之间施打高压旋喷桩形成竖向隔水帷幕,在强透水层的承压水采用井管降水的方法来控制基坑地下水,但降水井的深度要适当。经过工程实践验证表明,弱透水层的潜水、承压水的处置措施得当,可为富水复杂环境地质条件下的深基坑工程的设计与施工提供借鉴。     

深基坑多层承压含水层中混合井降水技术优化研究

对于多层承压含水层中的深基坑工程而言,水文地质条件复杂,基坑施工常因隔水层厚度不足或水力坡降过大导致坑底突涌,盲目地进行坑内降水又会造成基坑渗流场突变、基坑内外水位差过大等问题。因此,地下水的有效控制成为基坑开挖成败的关键。以某深基坑降水工程为实例,通过理论计算并结合数值模拟研究了不同承压非完整井的相关参数,包括滤管数量、位置和长度,揭示了相关参数对减压降水效果的影响,优化了隔、降组合降水措施。结果表明:采用混合井双滤管复合结构深井时降水成效显著,且第一、二承压含水层上、下分层滤管长度比接近1∶1时达到最优值,此时理论计算结果与数值模拟结果的相对误差最小,仅为6.81%,故对处于多层承压含水层等复杂水文地质条件下的深基坑工程可结合实际地层结构借鉴混合井分层滤管长度最优比值进行降水设计。     

环氧树脂封面层对球墨铸铁管生物膜的影响

以实际全比例非循环管道中试平台中水泥砂浆内衬球墨铸铁管为研究对象,通过分析生物膜的理化指标及微生物的群落结构来研究环氧树脂封面层对管道生物膜的影响.研究发现,相比于普通水泥砂浆内衬的球墨铸铁管,增加环氧树脂封面层后的管道不易吸附、沉积各种物质,对生物膜细菌丰度及群落结构均有影响,其管壁生物膜细菌总数为4.01×10⁴copies/cm²,可培养菌数量为1.40×10CFU/cm²,另外其物种丰度较高而多样性较低.因此增加环氧树脂封面层的水泥内衬球墨铸铁管是一种更为优良的管材.     

Application of a Modified Health Belief Model to the Pro‐Environmental Behavior of Private Well Water Testing

A social cognition model of health behavior, the health belief model, was applied to the pro‐environmental behavior of private well water testing. Conceptualizing environmental behaviors as health behaviors may provide new insight into pro‐environmental behavior change. A groundwater education program was provided to K‐12 children throughout New England. Both child participants and their parents completed surveys pertaining to private well water behavior. Results indicate that perceived barriers and socioeconomic status significantly influenced past well water testing of parent participants. Perceived barriers included: participants' concern related to the cost of treating their water, and how a well water problem would influence their property value. Parent participants also indicated that they would perform future well water testing if they received a reminder cue to action that might include: getting a discount or reminder in the mail, if a well testing program was available, and state or local requirement. Our findings reinforce the need for continued private well water research and parallels to additional environmental behaviors.     

西南岩溶山区分散供水水污染特征

西南岩溶山区分散供水在一定程度上缓解了人畜饮水矛盾,但分散供水水质都存在不同程度的污染。通过对西南岩溶山区三种主要的分散供水模式供水水质的调查、监测与分析,认为分散供水水质的污染由两部分组成：水源水污染与供水水污染;水源水污染源属于面状污染,供水水污染属于点状污染。分散供水水污染类型主要有生物型污染（肉眼可见物以及不可见微生物）、物理型污染（色度、浊度）以及化学型污染（pH值呈碱性以及生活垃圾、粪便引起的离子浓度异常）,并以生物污染为主。污染途径主要有降雨过程污染、径流过程污染（地表、地下径流以及引水过程）和储蓄利用过程污染。最后,针对岩溶山区分散供水特点,给出了相应的水处理方法。     

渤海某油田注水井筛管失效测试及原因分析

目的 对注水井防砂筛管失效进行原因分析,解决注水井防砂问题。方法 针对渤海某油田注水井的防砂筛管失效问题,打捞失效筛管,并对破损区取样,通过损伤部位宏观和微观形貌、关键区域EDS能谱成分测量及室内模拟测试与计算分析等手段,综合分析各部位的损伤特征及规律。结果 宏观和微观形貌分析结果表明,损伤区域呈现明显的冲蚀损坏特征,测试与计算结果得出损伤速率为1.299 mm/a,寿命预测约为0.35 a(4.2个月),与现场实际比较吻合。结论 地层砂在筛管外堆积,造成筛管堵塞,形成高压差,高速注入水冲击筛管外的堆积砂,形成含砂流体在筛管外表面附近区域的紊流,对筛管局部反向冲击形成含砂流体冲刷腐蚀,从而造成局部冲蚀破坏穿孔。为有效解决冲蚀损伤问题,建议后续采取砾石充填防砂方式。     

The costs of avoiding environmental impacts from shale‐gas surface infrastructure

Growing energy demand has increased the need to manage conflicts between energy production and the environment. As an example, shale‐gas extraction requires substantial surface infrastructure, which fragments habitats, erodes soils, degrades freshwater systems, and displaces rare species. Strategic planning of shale‐gas infrastructure can reduce trade‐offs between economic and environmental objectives, but the specific nature of these trade‐offs is not known. We estimated the cost of avoiding impacts from land‐use change on forests, wetlands, rare species, and streams from shale‐energy development within leaseholds. We created software for optimally siting shale‐gas surface infrastructure to minimize its environmental impacts at reasonable construction cost. We visually assessed sites before infrastructure optimization to test whether such inspection could be used to predict whether impacts could be avoided at the site. On average, up to 38% of aggregate environmental impacts of infrastructure could be avoided for 20% greater development costs by spatially optimizing infrastructure. However, we found trade‐offs between environmental impacts and costs among sites. In visual inspections, we often distinguished between sites that could be developed to avoid impacts at relatively low cost (29%) and those that could not (20%). Reductions in a metric of aggregate environmental impact could be largely attributed to potential displacement of rare species, sedimentation, and forest fragmentation. Planners and regulators can estimate and use heterogeneous trade‐offs among development sites to create industry‐wide improvements in environmental performance and do so at reasonable costs by, for example, leveraging low‐cost avoidance of impacts at some sites to offset others. This could require substantial effort, but the results and software we provide can facilitate the process.     

Transient design of landfill liquid addition systems

This study presents the development of design charts that can be used to estimate lateral and vertical spacing of liquids addition devices (e.g., vertical well, horizontal trenches) and the operating duration needed for transient operating conditions (conditions until steady-state operating conditions are achieved). These design charts should be used in conjunction with steady-state design charts published earlier by Jain et al., 2010a, Jain et al., 2010b. The data suggest that the liquids addition system operating time can be significantly reduced by utilizing moderately closer spacing between liquids addition devices than the spacing needed for steady-state conditions. These design charts can be used by designers to readily estimate achievable flow rate and lateral and vertical extents of the zone of impact from liquid addition devices, and analyze the sensitivity of various input variables (e.g., hydraulic conductivity, anisotropy, well radius, screen length) to the design. The applicability of the design charts, which are developed based on simulations of a continuously operated system, was also evaluated for the design of a system that would be operated intermittently (e.g., systems only operated during facility operating hours). The design charts somewhat underestimates the flow rate achieved and overestimates the lateral extent of the zone of impact over an operating duration for an intermittently operated system. The associated estimation errors would be smaller than the margin of errors associated with measurement of other key design inputs such as waste properties (e.g., hydraulic conductivity) and wider variation of these properties at a given site due to heterogeneous nature of waste.     

上坝村井水中重金属的污染状况和分布特征分析

调查了上坝村重污染区的上樟组、群樟组和群联组共29个井水中的pH、Eh和重金属.结果表明,上坝村井水的Cu、Pb含量不超标,但Zn、Cd和Mn浓度均值分别是国家生活饮用水卫生标准的1.24倍、1.96倍和10.8倍;Zn、Cd、Mn的浓度和Eh值随着水井离横石河越远而越低,即呈现上樟组群樟组群联组的关系;当Eh小于300mV或上樟组pH值大于5.5、群樟组pH值大于4、群联组pH值介于5.1—5.4时,随着Eh的降低或pH值升高,井水中Zn、Cd、Mn的浓度急剧下降且趋向零.     

Prevalence of organochlorine pesticide residues in groundwaters of Kasargod District,India

The Kasargod District is the northernmost district of Kerala State and is bound between the north latitudes 12°02′27″ and 12°47′35″ and east longitudes 74°51′54″ and 75°25′25″. The present study highlights the contamination levels of organochlorine pesticides in open wells of the Kasargod District from 2010 to 2011. Maximum contamination of organochlorine pesticides (OCP's) was observed for endosulfan followed by hexachlorobenzene (BHC). Contamination levels of α-endosulfan were higher at Panathur (58?µg?L^?1) and next to Periya (37?µg?L^?1) in the postmonsoon season of 2010. During premonsoon 2011, the residue levels of α-endosulfan were higher at Panathady (56?µg?L^?1) followed by Rajapuram (40?µg?L^?1). Contamination levels of the BHC isomers exhibit the order of γ-BHC?>?α-BHC?>?β‐BHC, showing that γ-BHC represents 62% of the total OCP residues in premonsoon 2010. Among the studied OCP's, concentration levels of DDT were below detection limit. Maximum concentrations of the sum of all OCP residues were observed at Mulleria and Cheemeni (premonsoon 2010), followed by Panathur and Periya (postmonsoon 2010), and lowest in Panathady and Rajapuram (premonsoon 2011). Residues of OCP's were lowest in Paettikundu and Cheravatur in all the three seasons.