顺向岩质高边坡支护设计方案确定思路探讨

顺层岩石高边坡工程在各类边坡工程中比较常见,也是边坡工程的一个工程难点。这是由于存在层间的软弱夹层和顺坡向的层理结构,会对工程造成较大的影响。在对顺向岩石高边坡进行开挖时需要对其进行预加固,为了降低成本和治理难度,必须选择合适的坡率进行放坡。文章对顺层岩质边坡的稳定性进行了探究,并提出了顺向岩质高边坡支护工程的设计思路。     

基于Midas的公路顺层岩质边坡破坏机理研究

公路边坡安全性是其稳定施工、有效运营的必要条件,针对公路顺层岩质边坡的稳定性及破坏机理的特点,本文对某公路顺层岩质边坡进行了现场勘察及室内试验,获取其边坡坡形、材料参数,利用MidasGTS有限元软件对其进行数值模拟研究,从岩体位移和应力两个角度对顺层岩质边坡稳定性及破坏机理进行分析讨论,较为真实地模拟出顺层岩质边坡破坏运动渐进过程。     

考虑软弱夹层的含孔洞大理岩力学特性模拟分析

天然岩体中常含有孔洞和软弱夹层等缺陷,为研究含1条软弱夹层与中心孔洞的大理岩在单轴压缩作用下的破坏模式和力学特性,采用数值模拟软件RFPA2D对试样破裂过程进行了模拟。结果表明:软弱夹层的存在改变了大理岩试样的破坏模式,当软弱夹层强度比较低,厚度比较大时,软弱夹层下部的大理岩基本不出现破坏;当软弱夹层强度不变时,大理岩试样的峰值应力随着软弱夹层厚度的增加而减小,峰值应力对应的应变随着软弱夹层厚度的增加而增加;当软弱夹层厚度不变时,大理岩试样的峰值应力随着软弱夹层强度的增加而增加,峰值应力对应的应变随着软弱夹层强度的增加而减小。研究结果对比揭示了不同厚度和强度软弱夹层含孔洞大理岩的破坏模式和力学特性,可为软弱夹层上部建设的岩体工程失稳破坏提供一定的参考。     

二叠系炭质页岩软弱夹层蠕变特性研究

二叠系炭质页岩软弱夹层在石灰岩矿山中分布广泛,因其力学强度低、流变效应显著等特点常成为石灰岩矿山边坡的薄弱部位,严重影响边坡的稳定性.以某典型石灰岩矿山边坡中的二叠系炭质页岩软弱夹层为研究对象,开展了常规剪切试验和剪切蠕变试验,对比分析了软弱夹层的常规抗剪强度与长期抗剪强度,以揭示软弱夹层的蠕变特性,结果表明:在常规剪...     

预裂爆破在我矿的应用

南京白云石矿应用预裂爆破技术处理边坡工程是切实可行的,利用它的不偶合作用,减轻对边帮保留岩体的破坏程度。根据岩石性质,合理地确定预裂爆破工艺参数至关重要,另外为保证预裂爆破效果,还应注意钻孔的施工质量,即预裂孔的孔位、角度,方向和深度均应符合设计要求。     

爆破与边坡稳定

为取得最佳爆破效果，且使边坡稳定，对影响边坡稳定的诸项穿爆参数进行了探讨。采用缓冲、预裂、光面和减震等特殊控制爆破技术，是消减爆破地震效应、增加边坡稳定性的有效措施、针对黄麦岭磷矿现场试验总结出六点经验。     

贵安新区清杨路某岩质边坡爆破震动监测与分析

贵安新区清杨路段一高陡岩质边坡在施工期间受周围路面爆破震动影响较大,为揭示爆破地震波对边坡岩体的影响及其在边坡岩体中的传播规律,在边坡马道岩体内部安装IMS加速度计传感器及岩体表面布置TC4850爆破测振仪,通过两种传感器接收相同爆源的波形,分析了爆破地震波在传播过程中的特征,得到了坡表爆破振动衰减规律与边坡内部岩体振动加速度衰减规律。结果表明爆破地震波在岩体内部加速度与坡表的振动速度相比,具有振动小、衰减较快的特点,且爆破波形持续时间较短、首次显现波峰后呈单调持续衰减。     

复杂矿岩露天分层爆破技术优化研究

以云南磷化集团有限公司尖山磷矿为背景,对复杂矿岩露天分层爆破技术进行了优化研究。分析研究现场采集测试的爆破振动对尖山磷矿周边村庄建(构)筑物的影响,并根据现场工程地质条件的多样性,对矿山现有爆破技术相关参数进行优化,确保爆破地震波小于国家规定的爆破振动安全允许标准,不会对民房结构造成损伤。建立尖山磷矿矿山开采爆破振动地质力学数值模型;建立以岩体声速降低率为基准量的岩体爆破累积损伤扩展模型,研究边坡的累积爆破振动损伤效应,为后续矿山开采爆破提供参考,以确保边坡安全。     

光面爆破在边坡开挖中的应用研究

为了减小爆破作业对坡面的扰动及损伤,控制开挖坡面的平整度,减少边坡支护的工程量,节约施工成本,通过光面爆破技术在边坡开挖中的应用案例,对比分析了光面爆破与普通爆破的施工效果。采用显示动力学分析软件ANSYS LS-DYNA模拟了不同装药参数下岩体的破碎过程,根据数值模拟的结果,探讨了爆破设计参数、施工工艺、起爆网路对爆破效果的影响。结果显示:孔内采用连续装药时被爆岩体周围破碎圈较大,采用间隔装药的光面爆破能有效控制边坡的超欠挖现象;间隔装药距离大于70cm时,被爆岩体破碎不充分,间隔装药距离小于70cm时,周围岩体损伤严重,不利于预留边坡的稳定,间隔装药距离为70cm时,开挖岩体破碎较为充分且预留边坡损伤较小,可以取得较好的爆破效果。研究成果具有较强的应用及推广价值。     

我国部分石灰石矿山边坡状况与分析

我国石灰石矿大都为海相沉积型矿床,组成露天矿边坡体软硬相间的岩体影响边坡稳定性,而形成层状结构的边坡体,多数层理面发育,构成顺层边坡,当层面在边坡面上出露时,极易形成顺层平面滑坡,其次,局部也发生楔形破坏。就考察的石灰石矿采场生产中存在的主要问题,已影响矿山安全生产,该加强边坡管理与维护。     

Fire testing of upholstered furniture and bedding

Considerable concern has been expressed about the increasing number and changing pattern of fires and the fact that modern upholstered furniture is relatively easy to ignite and, once ignited, burns rapidly to produce large quantities of smoke and toxic gas. This led to a number of major research programmes and to the evolution of a number of test procedures in the UK. The first major test procedure was published in 1976 by the BPF in conjunction with RAPRA, BRMA and FIRA. An important aspect of this approach was the linking of ignition and rate of initial burning data with the application of the product and the environmental hazard. It was evolved within a short period of time to proved furniture designers and specifies with a means of avoiding products of high risk. The DOE/PSA are using a comprehensive series of Fire Retardant Specifications to control and specify their upholstered furniture and bedding. Specifications have been developed which enable individual components and sub-assemblies as well as the final product to be characterized in terms of ignitability and burning characteristics, i.e. temperatures, smoke, and carbon monoxide production. BS DD58 and BS 5852 Part1, ignitability tests for upholstered seating are essentially a combination of BPR and DOE/PSA test procedures. Cigarettes, gas flames and wooden cribs are used for the ignition sources and are positioned on a composite seat/back test rig.     

Fire behaviour of beds and bedding materials

Full-scale fire tests on domestic beds fully equipped with bedding materials have been carried out in an experimental compartment-corridor facility at the Fire Research Station, Borehamwood, U. K. Mattresses made of hair, spring interior, foam rubber and polyurethane of various types, together with mattress covers of cotton, flame-retarded cotton or proofed nylon were studied. The effectiveness of protective hair or glass fibre interlining was examined. The study has shown that a rapid development of fire in bed and bedding materials can take place with certain combinations of mattresses and their covers. The types of covers extremely important in overall fire development, particularly with polyurethane mattresses. A substantial improvement in the fire behaviour of many of the principal types of beds tested can be achieved by a careful selection of bedding materials, such as the type of mattress cover, and in certain cases by the use of protective interlinings.     

Home bedding modifies ultrasonic vocalization of infant bank voles

Bank vole,Clethrionomys glareolus, pups, similar to many other infant rodents, emit ultrasonic vocalizations when they are removed from the nest and cooled. Infants exposed to bedding from their home cage produced fewer and shorter calls than infants tested without bedding. Sound frequencies were significantly higher in infants exposed to home bedding than in other experimental groups. These results provide evidence that infant bank voles are able to identify the presence of home bedding, probably on the basis of odor. This appears to be the first report of shifts in frequency of pup ultrasonic calls in response to olfactory cues.     

The influence of thermal processing on the structure and composition of the surface of copper bedding

The surface of a copper plate for compounding is studied before and after its oxidation. The heat treatment in the air in the temperature range of 100–200°C for 10–40 min enables the formation of a thin solid layer of copper oxide, CuO, eliminates the porosity of the surface of the copper plate, modifies its micro-structure, and substantially increases the surface maturity, and thus increases the adhesion in the Cu-polymer system. This phenomenon was proved by Auger spectroscopy (ASS), scanning electron microscopy (SEM) and atomic forced microscopy (AFM).     

集成平板膜MBR处理列车卧具洗涤废水

某铁路局洗涤中心采用转鼓格栅-混合调节-一体化MBR反应器-次氯酸钠消毒组合工艺处理列车卧具洗涤废水,介绍了工艺流程设计、主要构筑物设计参数以及工程运行情况。运行结果表明,出水一直稳定达到GB/T 19923—2005《城市污水再生利用工业用水水质》中洗涤用水水质标准和DB 11/471—2007《洗衣回用水水质要求》中最严格的指标要求。     

Lower temperature hydrothermal pretreatment improves the anaerobic digestion performance of spent cow bedding

The anaerobic digestion (AD) performance of spent cow bedding was investigated with different hydrothermal pretreatment (HP) conditions. Spent cow bedding was pretreated with low temperatures (50, 70, and 90℃) and different pretreatment times (2-72 h) with ammonia and without ammonia. The results showed that spent cow bedding was a good raw material for AD. After pretreatment, the concentration of volatile fatty acids (VFAs) in the group of hydrothermal pretreatments with ammonia (HPA) was higher than that in the HP group at the same pretreatment temperature and time. The optimal pretreatment condition was achieved with an HPA of 50℃ holding for 72 h. At the optimal condition, the highest concentration of VFAs was 1.58-10.85 times higher than that of the other pretreated groups. The highest hemicellulose and lignin removal rates were 58.07% and 10.32%, respectively. The highest methane yield was 163.0 ml·(g VS)^-1, which was 48.9% higher than that of the untreated group. The VFAs, pH, and reducing sugars showed positive relationships with the methane yield. Therefore, HP at low temperature can enhance the AD performance of spent cow bedding.     

Revisiting flexible polyurethane foam flammability in furniture and bedding in the United States

The flammability of flexible polyurethane foam has been well studied to date, via smoldering and flaming ignition. Its contribution to fire loss in the United States has also been well documented, as the flammability of this material will contribute to large fire events when not protected from ignition and heat sources. Despite this known fire risk, fire protection approaches for polyurethane foam are being questioned in regards to fire protection performance, as well as proven and hypothesized concerns over health impacts before and after fire events. The flammability of flexible polyurethane foam in furniture and bedding is a clear and present danger that must be addressed, and this article discusses the current available technologies for fire protection, with pros and cons of these approaches. Known physical and chemical behavior of these foams in fires is discussed, as well as how this behavior contributes to large fire events. Finally, issues that still need further research and information to definitively address the polyurethane foam flammability in the United States is discussed.     

Soil nitrogen mineralization in a soil with long-term history of fresh and composted manure containing straw or wood-chip bedding

Long-term effects of fresh (FM) versus composted (CM) beef manure application to barley (Hordeum vulgare L.) on potentially mineralizable nitrogen (N ₀ ), and mineralizable nitrogen (N) pools, were evaluated in a clay loam soil in southern Alberta, Canada. A suite of laboratory-based indices were evaluated for prediction of soil N supply. The treatments were three rates (13, 39, 77 Mg ha^?1 dry wt.) of FM or CM containing either straw or wood-chip bedding, 100 kg N ha^?1 as inorganic fertilizer, and an unfertilized control. Treatments were fall-applied annually for 8 years (1998–2005). Soil samples (top 15 cm) were collected in spring 2006. The medium and high rates of organic amendment resulted in increases in N ₀ , and readily (Pool I) and intermediate (Pool II) mineralizable N pools in ranges of 140–355 % compared with the average of the fertilizer and control treatments. Fertilizer application had no significant effect on mineralizable N pools, but increased the mineralization rate constant (k) compared with the control. Application of FM and use of straw bedding resulted in a greater quantity of readily available and intermediate mineralizable N, and also increased the rate of N turn-over as indicated by greater values of k, compared with CM and wood-chip bedding. Among laboratory-based measures of soil N supply, CaCl₂–NO₃ (r² = 0.84) and NaHCO₃-205 (r ² = 0.79) were strong predictors of plant N uptake (PNU). Increased soil mineralizable N did not translate into greater barley dry-matter yield or PNU. Composted beef manure and use of wood-chip bedding can be recommended as alternatives to FM and use of straw bedding for barley production is Southern Alberta.     

钴基催化剂上氢解反应的研究

制备了一系列不同金属含量的Co/SiO2加氢催化剂,考察了催化剂非原位还原条件、进料空速、氢分压变化对其氢解反应影响。结果发现,钴基催化剂在非原位还原后进行反应时有氢解反应伴随发生。催化剂上金属含量越高、还原温度升高和还原时间延长,氢解反应越明显;较高的进料空速及较高的氢分压有助于抑制氢解反应的发生。