Problems of soil and groundwater pollution in the disposal of “marble” slurries in NW Sicily

This work deals with disposal of slurries generated during the cutting and polishing processes of slabs of decorative sedimentary carbonate rocks in the north western Sicily. At present, they are used as fillers of dismantled quarries near the sawmills and, as a final step of reclamation, are covered with earth layers. In spite of such inexpensive solution, there is lack of knowledge about the composition of the waste. In order to assess if there is any threat for the environment and to suggest indications for alternative solutions, such as recycling or inactivation processes, the slurries were analysed by XR diffraction, simultaneous thermal analysis, ICP/MS, ionic chromatography, FTIR, UV-Vis, COD and TOC measurements, grain size analysis. Results indicate that the slurries can threaten the groundwater, because of the high chemical oxygen demand; furthermore they can modify the mechanism of groundwater recharge, because of their grain size distribution. Some laboratory tests show that, even in very aggressive conditions, the solid pollutants persist in the waste and slowly release into water the products of their degradation. The slurry therefore should be subjected to inactivation treatment before disposal or, alternatively, recycled as secondary raw material for a suitable process.     

钠土泥浆在构造破碎带型复杂地层钻进中的应用

应用钠土泥浆,解决了锡坑矿区复杂地层钻进中运用其它措施难以解决的塌、漏、掉等问题,保证了后续施工的钻孔质量,提高了钻进效率和经济效益。通过钠土泥浆与钙土泥浆及其它无固相冲洗液类比分析,得出了钠土泥浆在该矿区取得好成效的机理。针对赣南构造破碎带型复杂地层钻进中存在的问题,借鉴锡坑矿区的成功经验,提出应重视对钠土泥浆的研究和应用的建议。     

Analysis of the Dynamic Performance of an Underground Excavation in Jointed Rock under Repeated Seismic Loading

Results from field observations of dynamic behaviour of an underground excavation have been compared with numerical studies of the rock deformation history. The field behaviour shows progressive accumulation of rock displacement and excavation deformation under successive episodes of dynamic loading. It is possible to reproduce the modes of rock response quite well using a Distinct Element model of the rock mass, but the way displacements develop is dependent on the joint model used in the analysis. It is suggested that, in rock masses subject to repeated dynamic loading, excavation design may need to take account of the prospect of repeated episodes of transient loading at the excavation site.     

金刚石粒度对孕镶金刚石钻头性能的影响

孕镶金刚石钻头已获得了广泛的应用,但人们对其性能和钻头金刚石参数间的一些问题仍需进一步认识。本文通过理论计算得出了钻头唇面上金刚石的分布模型,其结论与实际相吻合;并以此为依据,探讨了金刚石粒度对钻头性能的影响     

Post-earthquake investigation on several geosynthetic-reinforced soil retaining walls and slopes during the Ji-Ji earthquake of Taiwan

This paper gives an overview on the application of geosynthetic-reinforced soil structures in Taiwan. Taiwan has an unique topography and geotechnical conditions that rendered a less conservative and more challenging design compared to that of North America, Europe and Japan. The Ji-Ji (Chi-Chi) earthquake of 1999 gave an opportunity to examine the behavior of reinforced soil structures. The performance of several modular-block reinforced soil retaining walls and reinforced slopes at the vicinity of the fault was evaluated. Reinforced structures performed better than unreinforced soil retaining walls. The failure cases were highlighted and the cause of failure was identified. The lack of seismic design consideration could be a major cause of failure. The compound failure mode, the inertia force of the blocks, and the connection stiffness and strength relative to the large dynamic earth pressure, were among major items that would warrant further design consideration.     

大跨度斜拉桥钢塔施工阶段制振用TMD、TLD装置及其性能试验

本文以南京长江第三大桥为例,研制了用于钢塔施工阶段涡激振动响应制振的制振器TMD和TLD。对制振装置以及其所采用的一些关键技术进行了说明。通过振动台试验测试了制振器的动力特性。根据试验结果,对TMD的工作性能,即装置的频率特性、阻尼特性、起动时所需的外激励水平及装置的框架刚度等,进行了评价分析;对TLD实现了其阻尼方案的优化,并确定了其工作时的阻尼隔栅状态。确认了制作完成的制振器具有良好的工作性能。     

高放处置罐铁释放诱发膨润土矿物相变研究进展

作为高放废物处置罐候选金属材料,低碳钢在处置库服役期间,其腐蚀产物侵入缓冲屏障,导致缓冲材料矿物相变与性能变异,威胁多重屏障体系的长期安全稳定。本文详细综述了国内外处置库深部还原环境所处的弱碱性化学场与中低温度场的变化趋势,认为处置库深部化学-温度还原条件可导致处置罐Fe腐蚀释放Fe~(2+)。在处置库长期运行过程中,蒙脱石与Fe~(2+)接触发生矿物相变,一方面Fe~(2+)置换蒙脱石八面体晶格中的Al~(3+)和Mg~(2+),还原Fe~(3+)或直接占据空位,生成次生矿物;另一方面Fe~(2+)交换蒙脱石层间的Na~+、K~+和Ca~(2+),转化为铁基蒙脱石。矿物相变可诱发缓冲屏障性能变异甚至退化。基于\"抗矿物转化\"理念,提出了下一阶段缓冲材料矿物相变研究方向,为地下实验室碳素钢选型、缓冲屏障验证试验设计以及屏障体系安全评价提供科学依据。     

CG-5重力仪的漂移与寿命

漂移及其线性度是重力仪最重要的性能指标,在很大程度上决定了其精度和寿命。对14台CG?5重力仪漂移数据的分析表明,多数仪器使用2年后的平均漂移率约在(0.7~1.7)×10-5 m/s2/d之间。以此为基础,结合厂家提供的相关数据,对CG?5重力仪的使用寿命进行了推测。得到北纬40°地区,仪器平均寿命约10年的结论。     

渤钻低密度固井水泥浆降低煤层气储层伤害的实验

针对煤层气井传统的固井水泥密度较大,在固井过程中产生较大压差,影响半径较大,且滤液成分矿化度较高,持续对储层产生伤害的问题,通过对比渤海钻探所使用的低密度固井水泥浆(统称渤钻浆)和常规固井水泥浆的失水量、滤液性能和稠化时间,并通过分析其滤液成分、电导率、渗透率回复率和计算污染半径,评价了渤钻浆降低煤层气储层伤害的能力。结果表明:渤钻浆失水量比常规固井水泥浆小一半,并且滤液黏度高、矿化度低和电导率低,使渤钻浆污染的煤样渗透率降低为28.97%(常规水泥浆污染的煤样渗透率降低为65.87%),渗透率恢复率为89.81%(常规水泥浆渗透率恢复率为61.18%)。综合来看渤钻浆不仅密度低,形成压差小,保证煤层稳定,还减小污染半径,降低了对煤层气储层的伤害。     

水合物地层低热固井水泥浆用相变微胶囊的制备及应用

当深海固井遇到天然气水合物地层时,由于水泥浆水化放热,导致水合物的相变平衡条件发生改变,诱发水合物分解,引起二界面胶结质量下降等问题。为提高水合物地层固井质量,可向水泥浆中添加具有吸热控温作用的相变微胶囊,可有效降低固井水泥浆的水化升温。基于此,以配比石蜡为控温芯材、碳酸钙为壁材,利用自组装法制备了一种使用于深水水合物地层固井水泥浆控温微胶囊。由于固井水泥浆在达到水合物地层的过程中,外界温度环境复杂,单一相变温度的控温芯材极易失效。为扩展控温区间,选用切片石蜡与白油作为混合芯材,控温区间达到14.8~39.8 ℃。研究表明,该微胶囊表观形态良好、彼此无团聚,在热循环过程中,不易发生泄漏。与水泥浆复配后,对水泥浆流变性能无明显影响。在低掺加量时,微胶囊主要起降低水泥浆峰值温度的效果,并提升水泥石整体力学强度;高掺加量时,微胶囊既可以有效降低水泥浆峰值温度,也可以明显地延缓水泥浆放热速率。