天山南坡高冰川覆盖率的木扎提河流域水文过程对气候变化的响应

木扎提河是天山南坡冰川面积覆盖率最大（48.2%）的河流, 流域径流过程对气候变化极为敏感, 为了合理管理和规划水资源, 确保水资源的可持续利用, 亟需定量评估气候变化对该流域水文过程的影响。以VIC-CAS分布式水文模型为计算平台, 利用实测的径流和两次冰川编目间的冰川面积变化数据开展了模型的多目标参数化校正和验证, 有效提高了模拟结果的“真实性”, 然后通过数值模拟结果结合观测数据定量解析了流域径流的组成、 变化特征及对气候变化的响应机理。结果表明： 木扎提河总径流集中在暖季（5 - 9月）, 占全年总径流量的77.9%, 冰川径流、 融雪径流和降雨径流分别占总径流量的66.6%、 26.4%和7.0%。1971 - 2010年木扎提河流域气温和降水呈显著增加趋势, 由于降水的增加, 降雨和融雪径流均呈增加趋势, 但冰川径流呈现明显减少趋势, 导致总径流呈现下降趋势。在RCP4.5情景下, 未来该流域气温呈现明显升高趋势, 降水表现为微弱下降趋势; 气候变暖后, 更多降水以降雨形式发生, 未来降雨径流将明显增加, 降雪和融雪径流已于20世纪90年代达到峰值, 随后明显减少; 冰川面积将持续萎缩, 冰川径流于21世纪10年代达到拐点, 随后明显减少, 导致河道总径流量也将明显减少。     

Assessing model of highway slope stability based on optimized SVM

Considering the geological hazards attributed to the highway slope, using a common simple model cannot accurately assess the stability of the slope. First, principal component analysis (PCA) was conducted to extract the principal components of six factors (namely, bulk density, cohesion, internal friction angle, slope angle, slope height, and pore water pressure ratio) affecting the slope stability. Second, four principal components were adopted as input variables of the support vector machine (SVM) model optimized by genetic algorithm (GA). The output variable was slope stability. Lastly, the assessing model of highway slope stability based on PCA-GA-SVM is established. The maximal absolute error of the model is 0.0921 and the maximal relative error is 9.21% by comparing the assessment value and the practical value of the test sample. The above studies are conducive to enrich the assessing model of highway slope stability and provide some reference for highway slope engineering treatment.     

Main active faults and seismic activity along the Yangtze River Economic Belt: Based on remote sensing geological survey

The Yangtze River Economic Belt (YREB) spans three terrain steps in China and features diverse topography that is characterized by significant differences in geological structure and present-day crustal deformation. Active faults and seismic activity are important geological factors for the planning and development of the YREB. In this paper, the spatial distribution and activity of 165 active faults that exist along the YREB have been compiled from previous findings, using both remote-sensing data and geological survey results. The crustal stability of seven particularly noteworthy typical active fault zones and their potential effects on the crustal stability of the urban agglomerations are analyzed. The main active fault zones in the western YREB, together with the neighboring regional active faults, make up an arc fault block region comprising primarily of Sichuan-Yunnan and a “Sichuan-Yunnan arc rotational-shear active tectonic system” strong deformation region that features rotation, shear and extensional deformation. The active faults in the central-eastern YREB, with seven NE-NNE and seven NW-NWW active faults (the “7-longitudinal, 7-horizontal” pattern), macroscopically make up a “chessboard tectonic system” medium-weak deformation region in the geomechanical tectonic system. They are also the main geological constraints for the crustal stability of the YREB.     

New technologies and systems for high quality citrus fruit production,labor-saving and orchard construction in mountain areas of Japan

Novel technologies have been necessary for improving fruit quality and productivity of citrus,labor-saving and orchard conservation on steep slope lands since aging of growers and decrease in the number of successors is remarkable in mountain areas of southwestern Japan. The purpose of this paper is to introduce new technologies for improving citrus production that have been developed in recent years. A new fruit quality control system using drip irrigation and liquid fertilization technique combined with year-round plastic mulching was developed, and it enables high quality and stable citrus fruit production. Water and/or nutrient solution is automatically supplied through drip tubes that are laid under the mulching sheets to give adequate water stress, so as to improve sugar and acid content of fruit. A new transportation system for steep sloping citrus orchards, which is a combination of the monorail system and contour narrow paths, was suggested. A small walking cultivator was developed to explain the procedure of narrow path excavation. After introducing the narrow path, working hours for fertilizer and chemicalherbicide application were reduced. Disasterpr evention mapping of citrus orchards on slope landswas developed based on computer-aided seepage estimation and topographic data. The mapping can show zones of both ascending flow and descendingflow of underground water during heavy rains incitrus orchards. The mapping is considered to be effective for the management of orchards andprevention of erosion on slope lands.     

通过滑面应力状态评价滑坡稳定性

以黄河上游某大型滑坡为例,研究了有限元法在评价滑坡稳定性中的应用。具体操作过程是：建立滑坡的有限元模型,求出滑面上的应力状态,计算滑面上总的抗滑力与总的滑动力之比,最后评价滑坡的稳定性。通过对黄河上游某大型滑坡比较研究发现,采用有限元法比传递系数法得出的稳定性系数高0．07,这种差异属允许差异范围。采用有限元法计算该滑坡在天然与地震两种条件下的稳定性系数分别为1．14和1．1,可以认为滑坡在两种条件下的稳定性较好。该方法原理正确、操作简单、结果可信度高,有一定的适用价值。     

太行山片麻岩区坡地渗流集蓄技术

在分析国内外雨水利用历史、现状的基础上,对太行山片麻岩坡地的水文地质结构及特性进行了分析。结果发现,坡地的表层被一层双重、非均匀的复杂介质所覆盖,具体表现为“上覆土壤、下伏岩石”的“岩土二元结构体”;岩土二元结构坡地的空间变异性,特别是岩一土之间存在凹凸不平交界面的水文地质特性,为坡地侧向渗流的集蓄创造了条件,该技术创新了雨水集蓄的形式,在中国北方石质山地具有广泛的推广与应用价值。     

对数正态分布下边坡稳定性二元指标体系研究

安全系数不能考虑边坡系统中实际存在的不确定性,可靠性理论缺乏丰富的工程实践经验,因此,将工程实践经验丰富的安全系数与先进的可靠性理论相结合,建立传统安全系数与可靠性相耦合的二元评价体系具有重要的理论意义和应用价值.设安全系数服从对数正态分布,取系列的最大可能安全系数（中值安全系数）和变异系数,计算得到最大可能安全系数及在不同变异系数下的破坏概率Pfo从而可由最大可能安全系数和可靠性（R=1-Pf）共同度量边坡的稳定性.将最大可能安全系数与边坡可靠性相乘,对最大可能安全系数进行折减,得到边坡可靠的安全系数.根据折减后安全系数的极限状态,可计算出不同最大可能安全系数的临界变异系数和临界破坏概率.根据不同最大可能安全系数及它的临界破坏概率,绘出边坡稳定性分区图,并建立安全系数和破坏概率相结合的边坡稳定性判别的二元指标体系.文中提供了小样本条件下,利用3倍方差原理估计参数方差的计算方法,并给出了边坡稳定性二元指标体系的研究实例.     

Stability of elevated liquid-filled conical tanks under seismic loading,Part I—theory

Conical steel shells are widely used as water containments for elevated tanks. However, the current codes for design of water structures do not specify any procedure for handling the seismic design of such structures. In this paper, a numerical model is developed for studying the stability of liquid-filled conical tanks subjected to seismic loading. The model involves a previously formulated consistent shell element with geometric and material non-linearities included. A boundary element formulation is derived to obtain the hydrodynamic pressure resulting from both the horizontal and the vertical components of seismic motion acting on a conical tank which is prevented from rocking. The boundary element formulation leads to a fluid added-mass matrix which is incorporated with the shell element formulation to perform non-linear dynamic stability analysis of such tanks subjected to both horizontal and vertical components of ground motion. Although, the formulation was developed for conical vessels, it is general and can be easily modified to study the stability of any liquid-filled shell of revolution subjected to seismic loading. The accuracy of fluid added-mass formulation was verified by performing the free vibration analysis of liquid-filled cylindrical tanks and comparing the results to those available in the literature. © 1997 John Wiley & Sons, Ltd.     

Mechanism for the instability of slopes composed of granular materials

The mechanism of instability of slopes composed of granular materials was examined through a tilting-box experiment using an assembly of aluminium rods and direct shear tests. A detailed observation of the experiment and the simple physical model led to the following conclusion. Avalanching of granular materials is triggered by rotation of rods at the slope surface. The force inducing the rotation was caused by the weight of the particles transmitted through contact points. Therefore, the mechanism of avalanching of granular materials was not comparable to the shear mechanism that has been considered to be responsible for the instability of slopes made of granular materials. © 1997 by John Wiley & Sons, Ltd.     

综合物探方法在不稳定斜坡地质灾害勘察中的应用研究

不稳定斜坡体地形复杂、坡度大,表层土、石混杂,下部岩石裂隙发育,探测难度大,缺乏有效的物探手段精确圈定不稳定斜坡体的分布位置及空间赋存状态。用超高密度电法和微动探测相结合,推断了不稳定斜坡的范围及空间赋存状态。工程实地勘查表明,综合物探方法具有较高的可靠性,为地质灾害的治理打下了良好的基础。