预制自排水桩的抗挤土机理分析

基于抗挤土效应,提出了预制自排水桩的设计思想,采用土体固结理论,研究了预制沉桩过程中桩周土体超孔隙水压力的消散速度,分析了预制自排水桩的沉桩排水效果,并通过工程实例和现场测试进行比较分析和验证。结果表明,预制自排水桩具有较好的排水效果,可以起到消散桩周土超孔隙水压力的效果,从而抑制沉桩挤土效应。

潮州供水枢纽西溪厂房自排水减压井施工

潮州供水枢纽工程西溪厂房深基坑地质条件差,承压水头高,基坑开挖过程中成功地通过自排水减压井放水降低了基坑内的承压水头,确保了深基坑开挖的顺利进行。简要介绍了自排水减压井的施工技术要点,对同类工程中减压井施工有一定的参考价值。

深基坑厂房开挖自排水减压井施工质量控制

针对潮州供水枢纽西溪厂房基坑自排水减压井施工质量控制,简要介绍了目前国内外深基坑开挖采用甚少的自排水减压井施工技术要点。

真空预压工程自排水应用探讨

本文以某真空预压工程为实例,叙述自排水在真空预压过程中的创新应用。

预制自排水桩的试验研究

提出一种具有自排水概念的预制桩,通过室内和现场测试,对该种预制自排水桩的沉桩排水效果进行检验,并与普通预制桩进行桩身承载力和单桩竖向承载力的现场对比。结果表明:相比普通方桩,预制自排水桩具有良好的排水性能,桩侧砂槽尤其是"<"形侧槽可以起到竖向排水井的作用;同时,从桩身承载力及吊装安全性角度看,采用以侧槽和角点控制保护层的预制自排水桩可以较好满足使用要求,且作为摩擦型桩,预制自排水桩桩侧阻力有所增加,桩周土体固结速度又较快,使得预制自排水桩单桩竖向承载力稍高于普通方桩。

“荣勋砌块”及其生态挡墙技术在围垦中的应用

“荣勋砌块”及其生态挡墙技术,用于围垦建筑的挡土墙中,可以同时满足挡土排水、安全可靠和生态需要,其三维互通的超过20%孔洞率的特殊构造为水生物提供了良好的生息环境,并能以成本低和速度快的最优技术实现挡墙花园化,这种挡墙是全立面的,它自挡土、自排水,自卡锁、自定位,具有耐污保洁的柔性结构和“人性化”特性,有消浪效果。与传统挡墙相比,具有整体连锁、施工简便、减少占地、节省投资等许多优点。目前,该砌块及技术已在浙江、江苏等地推广应用。

试述单元式幕墙的设计要点

目前超高层建筑越来越多,各地超高层地标建筑一个比一个高。单元式幕墙是为超高层建筑而衍生出的新型幕墙形式,加强对单元式幕墙防水构造设计的研究,对促进幕墙技术的发展具有非常重要的作用。

石壕煤矿东翼区采空水治理方案研究

通过对东翼区水文地质情况的收集、整理、分析,查明东翼区采空水影响范围及变化规律,为东翼区水仓及瓦斯抽放等设备的撤除提供准确的资料,论证东翼区采空水治理方案的可行性,为矿节约人力、物力和财力。

Impacts of tourism development on the physical environment of Mussoorie,a hill station in the lower Himalayan range of India

Tourism in mountainous regions is a significant source of revenue generation. However, it has also been associated with many adverse environmental consequences. This study aims at assessing the negative impacts of the incessant upsurge in tourism development on the physical environment of Mussoorie, a well-known mountain tourist destination in India. The impact indicators for the region were identified and assessed by qualitative and quantitative analysis of field observations. The observations indicated the aggravation of traffic congestion, atmospheric pollution, undisposed solid waste, water scarcity and infrastructure unavailability as the prevalent issues, especially during the peak tourist months. The extent of the consequential damage to the environment was evaluated by conducting an assessment of tourism-induced human disturbance on the natural landscape of the town. Slope, slope aspect, vegetation cover, road network and drainage network were incorporated as thedetermining landscape attributes to prepare thematic maps of landscape quality(perceivable intrinsic properties) and landscape fragility(vulnerability to anthropogenic disturbances) using GIS technique. An absorption capacity map was finally prepared to characterize the study area into regions of different conservation needs. The results identified the need for planning appropriate preservation strategies for different tourist places in the town. The study can be used by the policy makers for implementing the regulatory measures against potential disturbances due to mass-tourism.

A New Treatment of Depression for Drainage Network Extraction Based on DEM

Depressions in landscapes function as buffers for water and sediment. A landscape with depressions has less runoff, less erosion and more sedimentation than that without depressions. Sinks in digital elevation models （DEMs） can be considered the real features that represent depressions in actual landscapes or spurious features that result from errors in DEM creation. In many hydrological and erosion models, all sinks are considered as spurious features and, as a result, these models do not deal with the sinks that represent real depressions. Consequently, the surface runoff and erosion are overestimated due to removing the depressions. Aiming at this problem, this paper presents a new method, which deal with the sinks that represent real depressions. The drainage network is extracted without changing the original DEM. The method includes four steps： detecting pits, detecting depressions, merging depressions, and extracting drainage network. Because the elevations of grid cells are not changed, the method can also avoid producing new fiat areas, which are always produced by the conventional filling methods. The proposed method was applied to the Xihanshui River basin, the upper reach of the Jialingjiang River basin, China, to automatically extract the drainage network based on DEM. The extracted drainage network agrees well with the reality and can be used for further hydrologic analysis and erosion estimation.

Numerical comparison of coal spontaneous combustion danger influenced by different methane drainage patterns in gob area

The influence of gas drainage on float coal spontaneous combustion in the work face with ＂U＂ style ventilation was studied. Numerical simulation was used to compare the mutative law of steady flow and density field in the gob area under different drainage conditions by solving the equation set, including mass, momentum, and component transition. Consequently, the sequence of drainage effect and safety was obtained. The result manifests that the more effective the drainage pattern is, the easier float coal spontaneous combustion is caused due to air being guided into the depth of the gob area when the drainage position is arranged in the gas accumulation area. If the widened scope of oxidation zone exceeds the upper limit of the work face advancing speed, nitrogen injection should be applied to decrease the probability of spontaneous combustion. Then, the pipe laying drainage in the upper angle is most economical and safe compared with other drainage patterns when only the situation of gas accumulation is controlled in the upper angle. Finally, drainage pressure must not be too great. Otherwise the drainage density will decrease even if hazard is caused by back flow possibly happening in the return outlet when the drainage position is arranged near the work face.

Recovery of Astaxanthin from Discharged Wastewater During the Production of Chitin

In this paper, studies were carried out to extract astaxanthin from discharged wastewater during the production of chitin and to reveal the scavenging effect of the obtained pigment on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical. Different ratios of dichloromethane/methanol (V/V) were used to extract astaxanthin. When the ratio of dichloromethane/methanol was 2:8 and the ratio between the mixed organic solvent (dichloromethane/methanol, 2:8, V/V) and wastewater was 1:1, the highest yield of pigment was obtained (8.4 mg/ 50 mL). The concentration of free astaxanthin in the obtained pigment analyzed by HPLC was 30.02%. The obtained pigment possessed strong scavenging ability on DPPH radical and IC50 was 0.84mg/ml.

CFD modelling of Iongwall goaf gas flow to improve gas capture and prevent goaf self-heating

CFD models have been developed to investigate the Iongwall goaf gas flow patternsunder different mining and geological control conditions.The Iongwall goaf wastreated as porous regions and gas flow was modelled as a momentum sink added to themomentum equation.Gas desorption from the caved goaf and destressed coal seamswithin the mining disturbed area was modelled as additional mass sources in the continuityequation.These CFD models were developed according to specific Iongwall layoutsand calibrated against field monitoring data.Two case studies were presented demonstratingthe application of CFD modelling of goaf gas flow characteristics for improved goafgas capture and the reduction of oxygen ingress into the goaf areas for self-heating prevention.Results from the case studies indicate that the optimum goaf drainage strategywould be a combination of shallow (near the face) and deep holes to improve the overalldrainage efficiency and gas purity.For gassy Iongwall faces retreating against the seam dip,it is recommended to conduct cross-measure roof hole drainage targeting the fracturedzones overlying the return corner,rather than high capacity surface goaf drainage deep inthe goaf.

Co-benefits of Local Air Pollutants and Greenhouse Gas Reduction Achieved by Hydropower Development in Xizang(Tibet) Autonomous Region, China

Hydropower development in Xizang(Tibet) Autonomous Region plays a vital role in co-control of local air pollutants and greenhouse gas(GHG) in China. According to emission factors of local air pollutants and GHG of coal-fired power industry in different hydropower service regions, we estimate the effect and synergy of local air pollutants and GHG reduction achieved by hydropower development in Tibet, examine the main factors constraining the effect and synergy, using correlation analysis and multiple regression analysis. The results show that: 1) During the period from 2006 to 2012, the effect of local air pollutants and GHG reduction achieved by hydropower development in Tibet decreased as a whole, while the synergy increased first and decreased afterwards. 2) The effect and synergy of local air pollutants and GHG reduction achieved by hydropower development in Tibet vary significantly across different hydropower service regions. The effect based on emission levels of Central China power grid(CCPG) and Northwest China power grid(NCPG) was more significant than that based on emission level of national power grid(NPG) from 2006 to 2012, and the synergy based on emission levels of CCPG and NCPG was also more significant than that based on emission level of NPG from 2010 to 2012. 3) The main factors constraining the effect and synergy based on emission levels of NCPG and CCPG included SO2 removal rate and NOx removal rate, the effect and synergy based on emission level of NPG was mainly influenced by net coal consumption rate. 4) Transferring hydropower from Tibet to NCPG and CCPG, and substituting local coal-fired power with hydropower can greatly help to co-control local air pollutants and GHG, transform the emission reduction pattern of the power industry and optimize energy structure.

浅析地下工程排水系统设计

本文针对地下工程的建设特点和不同类型，介绍了地下人防工程的排水形式与排水系统的设计。着重对地下车库的排水系统设计进行了阐述，希望为地下工程排水系统的设计提供一些思考。

对建筑给排水规范的一些看法

《规范》存水弯、水封术语解释欠妥，有关强制性条文似混淆了存水弯和水封概念，唯存水弯技术独尊，导致中国式的存水弯地漏没有适用性。自排水密闭地漏能排水，又可避免排水管气体对环境的污染，也能防止甲流等传播和蟑螂等动物进入室内，并可简化通气管系统。建议《规范》在修订时，给出地漏的术语，纳入行之有效的自排水密闭技术。

A new variational inequality formulation for unconfined seepage flow through fracture networks

Darcy's law only applying to the flow domain is extended to the entire fracture network domain including the dry domain.The partial differential equation(PDE) formulation for unconfined seepage flow problems for discrete fracture network is established,in which a boundary condition of Signorini's type is prescribed over the potential seepage surfaces.In order to reduce the difficulty in selecting trial functions,a new variational inequality formulation is presented and mathematically proved to be equivalent to the PDE formulation.The numerical procedure based on the VI formulation is proposed and the corresponding algorithm has been developed.Since a continuous penalized Heaviside function is introduced to replace a jump function in finite element analysis,oscillation of numerical integration for facture elements cut by the free surface is eliminated and stability of numerical solution is assured.The numerical results from two typical examples demonstrate,on the one hand the effectiveness and robustness of the proposed method,and on the other hand the capability of predicting main seepage pathways in fractured rocks and flow rates out of the drainage system,which is very important for performance assessments and design optimization of complex drainage system.

Applications of different criteria in structural damage identification based on natural frequency and static displacement

This paper presents a damage identification method that consists of a fusion sensitivity matrix that contains information on dynamic and static responses. Based on natural frequency and static displacement, the study defines and considers damage criteria such as 1D and 2D single and fusion load cases. To overcome the lack of sufficient information on damage identification in large-scale structures, the authors consider multiple responses to and objective descriptions of uncertainties and various criteria.According to the finite element model and the structural responses described and measured, the fusion methods and damage criteria treat uncertainty as non-probability intervals. As long as we know the bounds of uncertain parameters, the intervals of the elemental stiffness parameters in undamaged and damaged models can be obtained by interval technology. Two numerical examples—a damage-criteria numerical example and a 5-span with 25-bar truss structure in a space solar power station—are proposed. Both examples indicate the veracity of the interval method.