Crustal Growth Rate of the North China Platform:a Method of Estimating Mass Equilibrium between Crust and Mantle

The following equation is proposed in this paper to estimate the crustal growth rate of the North China Platform on the basis of mass equilibrium between the crust and the mantle:The results indicate that the mass fractions of the crust during different geological periods are close to the real mass fractions of the crust in the upper mantle and the whole mantle (2-2.5% and 0.5 -0.6%, respectively, Hofmann, 1986), and the discrepancy of the results is probably related to that the heterogeneous contribution of the mantle to the crust both in space and in element. The results also show that the mass of the Archaean crust is only half that of the Proterozoic crust, and the crustal mass remained unchanged from Proterozoic to Paleozoic. suggesting that the plate movement at least started from the Late Proterozoic.

Overhanging rock slope by design:An integrated approach using rock mass strength characterisation,large-scale numerical modelling and limit equilibrium methods

Overhanging rock slopes(steeper than 90°) are typically avoided in rock engineering design, particularly where the scale of the slope exceeds the scale of fracturing present in the rock mass. This paper highlights an integrated approach of designing overhanging rock slopes where the relative dimensions of the slope exceed the scale of fracturing and the rock mass failure needs to be considered rather than kinematic release of individual blocks. The key to the method is a simplified limit equilibrium(LE) tool that was used for the support design and analysis of a multi-faceted overhanging rock slope. The overhanging slopes required complex geometries with constantly changing orientations. The overhanging rock varied in height from 30 m to 66 m. Geomechanical modelling combined with discrete fracture network(DFN)representation of the rock mass was used to validate the rock mass strength assumptions and the failure mechanism assumed in the LE model. The advantage of the simplified LE method is that buttress and support design iterations(along with sensitivity analysis of design parameters) can be completed for various cross-sections along the proposed overhanging rock sections in an efficient manner, compared to the more time-intensive, sophisticated methods that were used for the initial validation. The method described presents the development of this design tool and assumptions made for a specific overhanging rock slope design. Other locations will have different geological conditions that can control the potential behaviour of rock slopes, however, the approach presented can be applied as a general guiding design principle for overhanging rock cut slope.

相平衡关系在《化工原理》单元过程强化中的应用

相平衡条件是传质过程的热力学极限,借此可以确定分离级数、液气比等操作参数,设计和优化分离工艺,探索体系极限。本文列举了蒸馏、吸收、萃取单元操作中相平衡的内容,说明通过改变温度、压力、浓度或增加促进剂可以改善相平衡,调整传质过程的控制步骤,从而对化工过程实现精准设计和调控,是过程强化的重要手段。对于这些能源密集型单元过程,相平衡模型的准确预测或模拟是高效分离或纯化、减少能耗和原料损失的必要保障。

基于磁力平衡的不倒杆稳定强化装置

基于质心原理和磁力作用,通过磁场分布建模、风场虚拟仿真、质心计算等设计了不倒杆稳定装置,并且通过风力实验和撞击实验评估了装置的性能,优化制作了在一定风力及撞击力作用下维持杆稳定不倒的实际应用装置.实验结果表明:杆长为35.00 cm的木杆成品装置,能够在风速为23.40 m/s时稳定不倒,能够在质量为装置总质量1/4的铁球以9.89 km/h以内的速度撞击下保持稳定.

基于极限平衡法和强度折减法的危岩稳定性分析

为了分析评价陡倾结构面相互组合切割形成的危岩体的稳定性,本文以龙寺CIV-1边坡危岩体为例,根据地质调查数据,建立了危岩体的简化地质模型、失稳概化理论模型以及在冻胀、地震、水力等因素影响下的力学分析模型,利用极限平衡理论推导出了危岩体的滑移稳定性系数和倾覆稳定性系数的无量纲表达式,重点分析了不同工况下危岩体的稳定性,并借助UDEC强度折减法对危岩体的形成、破坏机理进行分析研究。结果表明:不同工况下的危岩稳定性为天然工况>地震工况>暴雨工况>组合工况;层面与陡倾结构面的组合关系以及陡倾结构面的贯通程度直接控制着危岩体的稳定性和破坏模式。通过极限平衡法和UDEC强度折减法相结合的危岩体稳定性评价方法,不仅可以通过简单的数学公式高效地获取危岩体的稳定性,还可以通过力与变形的信息,直观的辨别出危岩体易失稳的部位,为陡倾结构面切割形成的危岩提供防治参考。

多频次爆破扰动对倾倒式危岩体稳定性影响分析

危岩体主控结构面岩桥段岩石有效发挥其抗拉或抗剪性能是维系倾倒式危岩体稳定的关键,而岩桥段岩石力学性能常因工程爆破扰动而劣化,导致危岩体稳定性持续降低。首先,基于极限平衡理论考虑衰减后的爆炸应力波对危岩体稳定性影响,构建倾倒式危岩体稳定性评价方法;其次,通过Lemaitre等效原理得到爆破荷载作用下岩桥段岩石细观累积损伤变量,根据岩石有效抗拉面积弱化得到抗拉强度劣化方程并通过试验结果进行验证;最后,根据抗拉强度劣化方程对危岩体稳定性评价方法进行修正,依托工程算例分析相关敏感参数对危岩体稳定性的影响。研究结果表明:频繁的爆破扰动会使主控面的力学性能劣化,危岩体随爆破强度的增大、爆炸应力波传播距离的减小,岩桥段岩石力学性能劣化加剧,其自身的稳定性系数衰减趋势增大且爆炸产生对危岩体的倾倒荷载相较于岩体力学性能劣化更为敏感。

平衡透析法测定加米霉素与猪、牛和羊的血浆蛋白结合率

为测定加米霉素与常见家畜的血浆蛋白结合率(PPBR),本试验建立猪、牛和羊血浆中加米霉素的高效液相色谱-串联质谱检测方法,并对该方法的专属性、检测限、定量限、标准曲线、提取回收率和精密度进行考察。采用平衡透析法测定不同浓度(0.1、0.5和2.5μg/mL)加米霉素与猪、牛和羊的PPBR。结果显示,在考察浓度范围内,加米霉素在猪、牛和羊血浆中的专属性较好,检测限和定量限分别为0.5和1.0 ng/mL,标准曲线呈现良好的线性关系(r>0.997)。加米霉素在猪、牛和羊血浆中的提取回收率介于91.2%~107.8%,日内和日间精密度相对标准偏差(RSD)分别小于6.59%和9.16%。加米霉素与猪、牛和羊的平均PPBR分别为(21.86±4.19)%、(27.51±6.95)%和(19.64±3.58)%,且在考察的浓度范围内无浓度依赖特征。本试验所建方法准确可靠,可用于测定加米霉素与猪、牛和羊的PPBR。本试验结果可为加米霉素的药物代谢动力学研究及其在兽医临床中的科学用药提供参考依据。

某锰矿露天废石场边坡稳定性评价及高陡边坡防治

矿山开采工作的地质变化容易导致地质灾害的发生,进而影响周边人们的生产生活。针对锰矿露天废石场的高陡边坡问题,利用极限平衡分析法对岩土体进行物理力学参数的分析,以分析滑坡面的受力状况及边坡稳定性因素。再使用三维快速拉格朗日分析法,并结合废石场设计图纸的数值,生成三维集合建模以分析滑坡面的边坡角和堆置高度。结果显示,圆弧形滑坡面在自重和地震作用中,整体安全系数下降20.21%~20.48%,沿基底接触面滑动安全系数降低18.56%~19.75%。废石场堆置高度的不断变化和边坡临界值的计算,得出合理边坡角为29°。为高陡边坡防治的治理方案提供技术参考。

MASS BALANCE SENSITIVITY TO CLIMATE CHANGE: A CASE STUDY OF GLACIER NO. 1 AT URUMQI RIVERHEAD, TIANSHAN MOUNTAINS, CHINA

In this paper the degree day mass balance model is applied to the sensitivity test of mass balance/ELA(equilibrium line altitude) to climate change of Glacier No.1 at Urumqi Riverhead, the Tianshan Mountains, China. The results demonstrate that the mass balance of Glacier No.1, which is of continental type and accumulates in warm seasons, is less sensitive than that of a maritime glacier. On Glacier No.1, air temperature rise of 1℃ or precipitation increase by 20% can cause the ELA shift 81 m up or 31 m down respectively. Air temperature and precipitation play the different roles in the mass balance formation, in which the mass balance hypsometry follows the temperature variations by the means of rotation against the elevation axis and it shifts in parallel with precipitation change. Assuming a future temperature rise of 2 ℃ the mass losing trend on Glacier No.1 can not be radically alleviated even if there is a precipitation increase by 30%.

The processes and characteristics of mass balance on the Urumqi Glacier No. 1 during 1958-2009

As a solid reservoir, a glacier can regulate regional water resources. The annual net mass balance directly reflects the fluctuation of the glacier and climate variability. Based on 51 years of mass balance observation data, the mass balance of Tianshan Mountains Urumqi Glacier No. 1 experienced a nine times positive balance fluctuation and nine times negative balance fluctuation. There were 35 and 16 negative and positive balance years, respectively. From 1996/97 to 2008/09, 12 consecutive negative balance years were observed at Tianshan Mountains Urumqi Glacier No. 1. These results demon- strate that the Urumqi Glacier No. 1 is experiencing a strong negative balance, and the strongest negative balance, -931 mm w.e. （mm water equivalent）, during the observation period occurred in 2008. In addition, the cumulative mass balance reached 13,709 mm w.e. in 2008. However, in 2009, the mass balance was positive at 63 mm w.e. The equilibrium-line al- titude changes with the fluctuation in the mass balance, and the effective mass balance gradient is 7.4 mrn/m. In this paper, the headwaters of the Urumqi River were analyzed using meteorological data from 1958 to 2009, including the average seasonal temperature and precipitation. The results showed that the main factor associated with the mass balance variation of Glacier No. 1 is the fluctuation in the summer air temperature, followed by changes in the precipitation.

An investigation on changes in glacier mass balance and hypsometry for a small mountainous glacier in the northeastern Tibetan Plateau

Mass balance is a key indicator of the sensitivity of glaciers to climate change. Field measurement is one of the most important ways to study the mass balance of glaciers. Based on observations of mass balance in the ablation zone of Shuiguan Glacier No.4, Qilian Mountains, China, combined with the balance ratio between accumulation and ablation, we established a linear relation between mass balance and altitude. The results show that the mean annual mass balance of this glacier was ~510 mm w.e. from 2010 to 2013. The uncertainty in the balance ratio value does not lead to a significant difference in the mass balance. The equilibrium-line altitude rose by 180 m from 1972 to 2013, while the accumulation–area ratio decreased from 0.68 to 0.25. These variations may be caused by changes in air temperature. Meanwhile, the glacier is at present not in a steady state, and it may continue to shrink by a further ~900 m, even without further climate warming. In the western Lenglongling Mountains, assuming that the glaciers are in a steady state and the Equilibrium-line altitudes(ELAs)remain similar, there will be only 46 glaciers left, covering a total area of 19.2 km^2, in other words, only 22.3% of the glaciers area in 1972.

Compositions,Proportions,and Equilibrium Temperature of Coexisting Two-feldspar in Crystalline Rocks

Compositions, proportions, and equilibrium temperature of coexisting two-feldspar in crystalline rocks are of great importance to classification in petrography and interpretation of petrogenesis. Crystalline rocks are usually composed of 4-6 minerals （phases）, depending on their independent chemical components and the equilibrium temperature of crystallizations. In general, number of mineral phases can be determined by the ＂Phase Rule＂. According to the mass balance principle, bulk composition of coexisting two-feldspar could be evaluated from the bulk chemistry of a rock, provided that the compositions of the coexisting mafic mineral phases containing calcium, sodium, and potassium oxides are determined, e.g., by microprobe analysis. The compositions, proportions, and temperature of two-feldspar in equilibrium can thus be simultaneously resolved numerically from bulk composition of the rock, by incorporating the activity/composition relations of the ternary feldspars with the mass balance constraints. Upon the numerical approximation method presented in this paper, better-quality, internally consistent data on feldspar group could usually be obtained, which would be expected more realistic and accurate in consideration of thermodynamic equilibria in the system of crystalline rocks, as well as bulk chemistry of a rock and the composing minerals.

改进的岩质凸块的超载储备极限平衡法

脱离模式是块体理论提出的有限可动块体的失稳模式之一。虽然直接塌落是地下工程中最常见的失稳现象,但是目前依然缺少适用的定量分析方法,这使得地下工程的开挖和加固设计缺乏必要的理论支撑。为此,提出了一种改进的考虑渐进破坏的岩块稳定分析方法。主要改进了3处:(1)引入超载基数和超载方向两个参数来量化描述储备荷载;(2)提出了Tan和Scal两种超载基数设定方式;(3)超载方向设定在节理锥的边界扇面上。算例验证结果表明,改进方法完全兼容现有双面滑模式的安全系数算法,实现了脱离模式的定量稳定性分析。最后,讨论了改进方法的刚度参数取值方法及其敏感性。

某高速公路岩质高边坡破坏机理及稳定性分析

以某高速公路开挖高边坡为例,根据其工程地质条件,利用工程地质分析法初步探讨了边坡潜在破坏模式,同时结合岩体质量分级、极限平衡法,全面系统地分析了该边坡的稳定性。研究表明:高边坡在外力作用下,临空面附近岩土体不断发生局部坍塌或滑移变形,滑坡后缘不断后退,宏观上表现出从前向后扩展的“牵引后退式”滑动模式;由CSMR得分可见:高边坡在自然状态下岩体级别均为Ⅲ级,处于基本稳定状态,破坏概率0.4;受工程开挖形成陡峭的临空面,开挖状态下岩体级别均为Ⅳ级,处于不稳定状态,破坏概率0.6;运用极限平衡法对破坏模式进行分析,可得边坡在天然工况下稳定系数为1.10,暴雨工况下稳定系数为1.04,均不满足安全储备。

剪切带构造-流体-成矿系统动力学模拟

剪切带构造成矿系统动力学模拟可以定量，并能展示成矿系统时空结构与发展，从而揭示其本质。可从质量平衡、输运反应耦合、转换界面成矿和动力分形弥散等四个方面对剪切带构造成矿系统动力学进行理论分析与数值模拟。质量平衡分析指出：（１）剪切蚀变作用过程中，各种物质组分发生了不同程度的迁移；（２）体积应变为增加型，金矿床定位于剪切带的扩容带中；（３）存在较大的流体与岩石比值，金矿体定位于流体流量最大部位。耦合成矿动力学模拟表明：（１）金属硫化物成矿作用发生于剪压构造变形岩相向剪张构造变形岩相转换的时空界面；（２）其决定因素是成矿元素的地球化学特性及成矿流体的特征和性状；（３）岩浆侵入后，形成以岩体为中心的温度梯度带，是热液成矿作用的主要动力之一；（４）成矿流体的流速可以促进混合热液的生长，剪切破碎带是强烈输运反应耦合成矿的有利场所。动力弥散作用过程理论分析与计算机模拟指出：（１）点源淀积弥散机制，Ｃ＝Ａρｖ２ｄｘｄｙｄｔｅ－ｋｒ／［２π（ｈ２－ｖ２ｔ）ｄｌ］；（２）分形弥散度，αｍ＝ｘｓ２Ｄ－１σ２（εｃ１－Ｄ）／２；（３）剪切带构造成矿系统是自相似的变形变质系统，在动力系统作用下，矿源系统与输运系统耦合，弥散作用发生；?

300MW煤粉锅炉燃烧产物中汞的分布特征研究

在对某 30 0 MW燃煤电站锅炉的煤、渣、底灰、飞灰进行取样后 ,通过对煤样、灰样、渣样中的汞进行定量测量 ,并借助于质量平衡分析方法计算烟气中汞的浓度 ,获得了煤在大型电站锅炉中燃烧时汞污染物的分布特征及其排放特性。图 5表 1参

天山乌鲁木齐河源1号冰川1959-2009年物质平衡变化过程及特征研究

以天山乌鲁木齐河源1号冰川1958/1959—2008/2009年度物质平衡资料为基础,研究了冰川的物质平衡变化过程及特征.结果表明:51a来1号冰川物质平衡经历了9次负平衡波动和9次正平衡波动,负平衡年与正平衡年之比为35∶16,负平衡年平均物质平衡-450mm,正平衡年平均物质平衡130mm,多年平均物质平衡-267mm.1997—2008年,该冰川连续12a的物质平衡观测结果均为负平衡年,并且总体上处于数值很大的强负平衡,直至2008年出现了历史上最大的负平衡,物质平衡量为-999mm.1959—2009年,累积亏损达-13 646mm(约-2 402.6×104 m3),即冰川平均较之1959年减薄了15.2m,这种长时期连续物质亏损状态对1号冰川是一个严峻的考验.

天山乌鲁木齐河源1号冰川物质平衡对气候变化的敏感性研究

应用度日物质平衡模式对天山乌鲁木齐河源１号冰川物质平衡及平衡线高度对气候变化的敏感性进行了研究．结果表明，位于大陆性气候区且具有暖季补给特征的乌鲁木齐河源１号冰川物质平衡对气候变化的敏感性要小于海洋性冰川，升温１℃或增加２０％的降水可引起平衡线上升８１ｍ或下降３１ｍ．此外，气温与降水在物质平衡形成过程中的作用是不同的，气温引起物质平衡剖面以旋转方式变化，而降水可导致其平移方式的响应．若未来升温２℃时，即使降水增加３０％，１号冰川向负平衡变化仍然不能得到遏制．

干燥方法和试件尺寸对加气混凝土等温吸湿曲线的影响

采用干燥剂法、70℃烘干法和105℃烘干法处理了2种尺寸（4cm×4cm×2cm和3cm×3cm×1cm）的加气混凝土试件，比较了3种干燥方法得到的试件干重差异．用静态称重法测定了70℃烘干的大小试件在不同相对湿度下的平衡含湿量，并用统计学方法进行比较，然后采用Peleg模型拟合了加气混凝土等温吸湿曲线．结果表明：70℃烘干法得到的试件干重比干燥剂法得到的试件干重多0．13％～0．16％，而105℃烘干法得到的试件干重比干燥剂法得到的试件干重少1．02％～1．06％．大小加气混凝土试件在相同相对湿度下的平衡含湿量并不相等，在中高相对湿度下小试件的平衡含湿量明显较小．不同干燥条件下大小加气混凝土试件拟合等温吸湿曲线有明显差异．在测试加气混凝土等温吸湿曲线时，推荐采用70℃烘干大试件．

溪洛渡水电站某危岩体稳定性及加固措施研究

在现场调查分析的基础上,提出了溪洛渡水电站某危岩体的两种可能失稳模式(剪切坠落或拉裂倾倒失稳),进而建立了相应的稳定性计算极限平衡力学模型,而且对危岩体的变形和破坏特征进行了数值模拟分析,分析结果表明,危岩体抗拉裂倾倒稳定性较差,剪切坠落失稳的稳定性系数较高。在稳定性分析的基础上,计算出危岩体倾倒失稳时,安全系数为1.5时的锚固力,进而提出了危岩体加固方案:充填凹岩腔+填充裂隙+预应力锚索+锚杆联合加固,数值模拟表明此加固方案效果良好。