深水河大桥桥墩边坡稳定性分析

深水河大桥桥墩边坡地处广乐高速深水河大桥段,其稳定性直接关系着桥墩桩基工程能否顺利施工和整段广乐高速的工程进度。本文采用定性分析和定量计算的方法对深水河大桥桥墩边坡稳定性进行了分析,定性分析主要是通过赤平投影法作图初步分析边坡局部可能出现的组合滑面破坏模式,再取典型的楔形体进行破坏模式分析,定量计算主要是采用Bishop法分别计算该边坡在不同工况下的稳定系数,从而对该边坡的整体稳定性进行评价,以便提出相应的治理措施。     

模糊评判在岩质边坡稳定性评价中的应用

在工程实践中,影响岩质边坡稳定性的因素众多,不同因素的影响程度不相同,具有不确定性,因此选择合适的方法对岩质边坡稳定性进行评价尤为关键。本文采用模糊综合评判方法对岩质边坡进行稳定性评价,首先阐明了如何建立模糊评判体系以及权重和隶属度的确定方法,然后以某岩质边坡为实例,采用模糊评判方法对其稳定性进行了评价,结果表明模糊评判的结果与实际情况较为吻合,说明该方法真实、有效,具有一定的借鉴意义。     

Improvement of soil aggregate stability by repeated applications of organic amendments to a cultivated silty loam soil

The objective of this study was to compare the effects of repeated field applications of three urban compost amendments and one farmyard manure amendment over a 9-year period on aggregate stability in a silty loam soil initially characterized by low clay and initial organic matter contents and poor aggregate stability. Three different aggregate stability tests with increasing disruptive intensities (fast wetting > mechanical breakdown > slow wetting tests) and different disaggregation mechanisms, were used. All of the amendments, which were applied at approximately 4 Mg C ha⁻¹ every other year, increased the organic carbon content and improved the stability of the aggregates against the disruptive action of water, as determined by each of the stability tests. However, the year-to-year variations in the aggregate stability that related to factors other than the organic inputs were greater than the cumulative increase in aggregate stability relative to the control. The positive effects of the tested amendments on aggregate stability were linked to their contribution to soil organic C contents (r = 0.54 for the fast wetting test and r = 0.41-0.42 for the mechanical breakdown and slow wetting tests; p < 0.05). The addition of urban composts had a larger positive effect on aggregate stability than farmyard manure at the majority of sampling dates. The addition of biodegradable immature compost, such as municipal solid waste (MSW), improved the aggregate stability through an enhanced resistance to slaking. The addition of mature composts, such as the co-compost of sewage sludge and green wastes (GWS) or biowaste compost (BW), improved the aggregate stability by increasing interparticular cohesion. The MSW compost was the most efficient in improving aggregate stability during the first 6 years of the experiment (average improvements of +22%, +5% and +28% in the fast wetting, mechanical breakdown and slow wetting tests, respectively, compared to the control treatment); this result was likely due to the larger labile organic pool of the MSW compost that was highly effective at stimulating soil microbial activity. After the first 6 years, the two other composts, GWS and BW, became more efficient (average improvements of +25%, +61% and +33% in the fast wetting, mechanical breakdown and slow wetting tests, respectively, compared to the control treatment), which was probably linked to the greater increase in soil organic C contents. Therefore, the application of urban compost to silty soil that is susceptible to water erosion was effective at improving aggregate stability and thus could be used to enhance the resistance of soil to water erosion.     

以高岭土为原料合成高稳定性介孔分子筛

以廉价的高岭土和硅酸钠为硅源,用水热法合成了介孔分子筛。采用X射线粉末衍射、Fourier变换红外光谱、热分析、N2物理吸附、扫描电子显微镜和透射电子显微镜埘样品进行了表征,同时研究了样品的热稳定性和水热稳定性。结果表明：长程有序的介孔分子筛平均孔径约为2．75nm：经900℃焙烧3h或100℃水热处理6d,样品的介孔结构不被破坏,说明样品具有高的热稳定性和水热稳定性。     

有机质对土壤气相抽提去除四氯化碳效率的影响

某重要岩溶地下水源地因附近农药厂排放含四氯化碳污水而受到严重污染,实验采用土柱通风试验模拟土壤气相抽提(SVE),研究环境温度为20℃,通风速率为40mL/min,土壤含水率10%,而土壤有机质含量分别为3.02%和0.13%条件下的两种供试土壤中四氯化碳污染物的去除过程.结果表明,土柱通风能有效去除土壤中的四氯化碳污...     

陶粒CANON反应器的接种启动与运行

通过CANON接种污泥,以人工配制无机高氨氮废水为对象,研究以陶粒为填料的CANON反应器启动与运行情况,结果表明:①陶粒可以作为CANON反应器合适填料,温度通过水浴控制在30℃±1℃,HRT为9 h、pH控制在7.00~8.08之间,经过60 d成功启动了CANON反应器,TN的去除负荷达到0.79 kg·(m3·d)-1;②在温度30℃时,陶粒CANON反应器中临界DO范围在1.12~1.69 mg·L-1之间,CANON反应器中短程硝化和厌氧氨氧化性能可维持稳定,高于此范围时,会出现CANON反应器中短程硝化不稳定现象;③在温度25℃,控制DO在1.01~1.54 mg·L-1之间时,尽管NO-3-N变化值与TN变化值的比值(δNO-3-N/δTN)略微偏离理论值0.127,为0.150~0.204,但CANON反应器脱氮性能趋于稳定,TN去除率最高为75.56%,TN的去除负荷最高达到0.97 kg·(m3·d)-1,这意味着CANON工艺的适宜温度范围至少可以降低至25℃.     

大渡河干海子滑坡稳定性研究

干海子滑坡位于大渡河流域,规模巨大.为研究该滑坡的稳定性,在对滑坡基本特征及变形破坏特征等深入研究的基础上,采用极限平衡法(Geo-slope软件)和有限差分法(FLAC-3D软件)对该滑坡的稳定性和应力应变特征进行了计算、模拟.稳定性计算模拟主要从深层、浅层及局部稳定三方面入手分析,计算模拟结果与滑坡的宏现地质现象均...     

极端冰雪条件下的顺层岩质边坡滑移稳定性分析

推导了典型岩石边坡在极端冰雪条件下的滑移稳定系数的表达式;通过计算分析,揭示了岩石边坡滑移稳定系数随裂隙内水深、坡高、坡角、滑面倾角等因素变化的规律及与冻深的关系,并绘制岩石边坡滑移稳定系数与边坡几何要素之间的关系图.研究表明,当考虑极端冰雪灾害影响时,岩石边坡滑移稳定系数发生较为明显的变化:随裂隙饱水程度、坡面角、主...     

Thermal decomposition mechanism of 65% lysine sulfate powder and its thermal stability based on thermal analysis

Lysine is widely used in the fields of food, medicine and feed, which generally appears in the form of lysine sulfate or lysine hydrochloride dust because of the high instability of the free L-lysine. The L-lysine Sulfate is in high risk of decomposition, spontaneous ignition and even the dust explosion, because the control temperature in its production process is high up to 90 °C. Thus, the thermal behaviors and its thermal stability of 65% lysine sulfate are experimentally explored in Air and Nitrogen using the simultaneous TG-DSC measurements. Results show: (1) the decomposition of 65% lysine sulfate can be divided into three stages both in the atmospheres of air and nitrogen, and most of the weight loss occurred in the first two stages, which are related with the decarboxylation and deamination process. (2) The effects of atmosphere on the decomposition of 65% lysine sulfate mainly occur at the third stage. In this stage, the weight loss in nitrogen is only 14.2%, which is much lower than that in air (34.3%), which is related to the oxidative degradation at high temperature. Besides, the active energy is slightly increased in nitrogen compared to that in air. (3) The initial temperatures of the decomposition of the 65% lysine sulfate are 145 °C and 155 °C, for the air and nitrogen atmosphere, respectively, which are much lower than that (260 °C) of the pure lysine.     

操作条件对超滤膜运行经济稳定性能的影响

采用正交实验的方法对棕榈油生产废水二级处理出水的超滤工艺条件进行考察和优化,并用膜通量衰减系数、平均跨膜压差及产水量各自加权相加所得综合指标来表征不同超滤操作条件下膜运行的经济稳定性能。正交试验结果表明,减小膜表面流速和产水率,提高处理废水温度均有利于系统经济稳定地运行;各运行参数对综合指标影响的大小顺序为:膜表面平均流速>产水率>温度;在保证出水质量的前提下,最佳组合操作条件为膜表面平均流速0.7m/s,产水率80%,废水温度30℃。