装配式管廊接缝渗水监测技术研究

管廊接缝是装配式地下综合管廊最容易发生渗漏的部位,管廊日常运营维护需对接缝渗漏水情况进行实时监控,以保证内部管线安全.本文根据装配式管廊结构特征设计了接缝渗漏水监测技术方案,并进行了室内模型试验和现场渗漏模拟测试验证.模型试验结果表明,渗漏检测系统定位精度可达±0.1m,现场测试渗水位置与实际渗水位置基本一致,设计的管廊接缝渗漏水监测技术能够及时、准确发现接缝渗水情况,且监测成本不高,可推广应用于装配式地下管廊接缝工作状况长期监测.     

湿法回收钒高氨氮废水处理工程实例

湿法提钒回收处理过程中的废水具有高硬度、高含盐、高氨氮等特征,采用预处理+负压亚沸碱析脱氨及微负压氨回收工艺,可使出水水质稳定氨氮达到15 mg/L以下,同时超级吸氨器以及两级氨水吸收罐可制得浓度为18％～25％的氨水作为产品,降低项目整体运行费用.     

Advances in statistical mechanics of rock masses and its engineering applications

To efficiently link the continuum mechanics for rocks with the structural statistics of rock masses,a theoretical and methodological system called the statistical mechanics of rock masses(SMRM)was developed in the past three decades.In SMRM,equivalent continuum models of stressestrain relationship,strength and failure probability for jointed rock masses were established,which were based on the geometric probability models characterising the rock mass structure.This follows the statistical physics,the continuum mechanics,the fracture mechanics and the weakest link hypothesis.A general constitutive model and complete stressestrain models under compressive and shear conditions were also developed as the derivatives of the SMRM theory.An SMRM calculation system was then developed to provide fast and precise solutions for parameter estimations of rock masses,such as full-direction rock quality designation(RQD),elastic modulus,Coulomb compressive strength,rock mass quality rating,and Poisson’s ratio and shear strength.The constitutive equations involved in SMRM were integrated into a FLAC3D based numerical module to apply for engineering rock masses.It is also capable of analysing the complete deformation of rock masses and active reinforcement of engineering rock masses.Examples of engineering applications of SMRM were presented,including a rock mass at QBT hydropower station in northwestern China,a dam slope of Zongo II hydropower station in D.R.Congo,an open-pit mine in Dexing,China,an underground powerhouse of Jinping I hydropower station in southwestern China,and a typical circular tunnel in Lanzhou-Chongqing railway,China.These applications verified the reliability of the SMRM and demonstrated its applicability to broad engineering issues associated with jointed rock masses.     

新发展阶段中国水资源安全保障战略对策

进入新发展阶段，中国水资源安全保障需要以“节水优先、空间均衡、系统治理、两手发力”治水思路为指导，厘清问题、研判趋势、优化对策，支撑新阶段水利高质量发展。本文在全面分析我国水资源安全保障存在的突出问题与面临形势基础上，阐述了新发展阶段中国水资源安全保障的基本思路与战略路径，从保证资源安全、构建国家水网、强化供水保障、建设美丽河湖、改善水环境质量等方面提出了战略对策和需要进一步回答的重大问题，以期为完善新发展阶段中国水资源安全保障战略，全面提高国家水资源安全保障能力提供有力支撑。     

湿热地区城市乔木冠层能量平衡观测及显热计算模型优化

植被冠层能量分配是认识和把握植被对城市气候调节作用的关键,显热是植被冠层能量的重要组成部分,直接作用于近地气温与人体舒适性.根据能量平衡原理(净辐射=显热+潜热+蓄热),通过植被、液流和微气候等参数在秋冬少雨季的连续、系统性观测,考察湿热地区典型城市乔木(杧果树,树高9.38 m,胸径0.621 m,冠幅8.60 m)的冠层能量分配及显热计算模型.乔木冠层各能量项均随太阳辐射而变:净辐射、显热、蓄热呈“单峰单谷型”日变化,潜热呈“单峰型”日变化,蓄热峰谷出现最早(8:30,16:30),说明植被随外界条件变化快速调整叶片及冠层温度,潜热较大值出现早(11:00)且持续时间长(5 h),说明植被持续有效地通过叶孔蒸腾散热.植被冠层日间获得的太阳辐射能量主要向周边空气散失,引起空气温升和加湿,二者作用的强弱随时间和天气条件而变,上午和晴天、多云天温升作用明显,而下午和阴天加湿作用显著.叶孔蒸腾消耗乔木冠层40％(晴天)～60％(多云天)的日总能量,并在阴天持续发挥作用使得植被净吸收周边空气的热量.冠层显热由叶片与空气温差和冠层空气动力学阻抗决定,以0.11 m/s为界区分自由和受迫对流,预测结果能较好表现乔木冠层的显热变化特征(RMSE=74.54 W/m2,R2=0.86,d=0.96).研究结果为认识和把握典型植被的城市气候调节效应提供基础数据和参考,为提升风景园林设计的环境效益和生态水平奠定科学基础.     

Lactobacillus Gasseri LGZ 1029 in yogurt: rheological behaviour and volatile compound composition

Yogurt preserves and enhances nutritional value of milk. In this study, we have compared several strains to determine the physicochemical, sensory, rheological and aroma characteristics of different yogurts. We used Lactobacillus gasseri LGZ 1029 (LG), commercial probiotic L. rhamnosus (LGG) and traditional fermentation strains Streptococcus thermophilus and L. bulgaricus (SL). Results showed that the flavour and texture characteristics of mixed-strain yogurts were obviously better than in single-strain yogurts. Addition of LG increased pseudoplastic behaviour, as shown by Herschel–Bulkley model analysis of rheological behaviour. The LG + SL group also had both the highest viscosity consistency index and thickening ability. In addition, a total of 57 volatile compounds were detected in yogurts and the fermentation with the addition of LG was mainly affected by ketones. Our study suggested that a yogurt with new attributes can be produced by using LGZ 1029.     

无黏结预应力框架结构的拆改加固设计

连续多跨的二层无粘结预应力混凝土框架结构按照改造需要拆成单跨框架结构,且增加一层。某一方向的预应力钢筋将全部切断。通过对多种改造加固方案的比选,最终确定了无粘结预应力钢绞线应力释放和重张拉法。通过与专业施工单位的共同配合,顺利完成了该工程预应力拆除改造关键技术,施工监测表明,通过施工监测表明整个拆改过程变形合理可控。本项目取得了较好的经济效应,且是改造项目中的绿色工程。     

斜拉索倾角对振动法测索力的精度影响

现有的基于振动的索力测试方法在推导过程中,多以水平索为模型,未考虑斜拉索倾角对索力识别精度的影响。为了分析倾角对振动法测索力的精度影响,以两端固支索为例,采用有限差分法求解索的模态参数,并由迭代法识别索力,研究倾角对索的模态参数和索力识别精度的影响。结果表明,采用第1阶频率识别小垂度索的索力,与采用第1阶或第2阶频率识别大垂度索的索力时,不考虑倾角的影响,索力识别的误差很大。     

荔浦市岩质崩塌形成条件及失稳运动特征

通过对荔浦市境内碳酸盐岩区岩质崩塌及该区域地质环境条件的调查,总结了岩质崩塌的规模、发育高度、控制结构面等发育特征,分析了岩质崩塌形成条件,并判断岩质崩塌的失稳运动特征。本文以一处危岩为例,用无人机进行三维扫描并分析其形成原因及预测其失稳运动特征。