Long-term soil moisture content estimation using satellite and climate data in agricultural area of Mongolia

The purpose of this study is to estimate long-term SMC and find its relation with soil moisture (SM) of climate station in different depths and NDVI for the growing season. The study area is located in agricultural regions in the North of Mongolia. The Pearson’s correlation methodology was used in this study. We used MODIS and SPOT satellite data and 14 years data for precipitation, temperature and SMC of 38 climate stations. The estimated SMC from this methodology were compared with SM from climate data and NDVI. The estimated SMC was compared with SM of climate stations at a 10-cm depth (r² = 0.58) and at a 50-cm depth (r² = 0.38), respectively. From the analysis, it can be seen that the previous month’s SMC affects vegetation growth of the following month, especially from May to August. The methodology can be an advantageous indicator for taking further environmental analysis in the region.     

乌东德水电站大坝防渗帷幕成幕影响地质因素分析及处理措施

灌浆工程为地下隐蔽工程,其地质条件约束着实际的现场施工工艺,且不同地质条件对应不同的岩石属性,并将直接影响着防渗帷幕的优化设计,同时地质条件分析不足也将给整个灌浆工程带来很多不确定的风险。目前,地质条件预测在隧洞开挖过程中的研究较充分,但在灌浆工程中地质因素的研究较少。本文以乌东德水电站大坝防渗帷幕工程为例,分析了对防渗帷幕成幕有影响的岩溶、角砾岩、断层、岩层走向与帷幕走向大角度相交及长大结构面等地质因素,并针对不同地质因素的特点,提出了采取浓浆回填、灌浆孔加密加深、灌浆压力及浆材动态调整等处理措施,为帷幕灌浆工程优化提供了必要支持。     

锦屏二级水电站隧洞无盖重高压固结灌浆试验

水工隧洞高压固结灌浆的目的是加固隧洞围岩、封闭隧洞周边岩体裂隙,提高隧洞围岩的整体性和抗变形能力,增强围岩抗渗能力和长期渗透稳定性。主要介绍了引水隧洞在未进行混凝土衬砌的条件下实施高压防渗固结灌浆施工的试验及其成果,为该类洞段灌浆设计和施工提供依据。     

含圆柱形弹性夹杂地基沉降量的解析解

研究各向同性地基中含一个圆柱形弹性夹杂的地基沉陷问题。考虑全场的应力、变形特征,运用复变函数的罗朗级数展开技术,构造合适的应力函数,结合夹杂的边界条件和无穷远的性态,获得了全场复势的解析表达。数值结果显示：由于两相材料剪切模量之比的不同,在某个范围内沉陷量大于基底中点沉陷;在这个范围之外,则小于基底中点沉陷。当夹杂埋深为夹杂半径的5倍以上时,就可以运用所得结果,而不致引起太大误差;含圆形隧洞和刚性夹杂的问题可作为特殊情况得到。     

列车荷载对平行换乘地铁车站深基坑变形影响

根据地铁车站轨道结构的特点,利用集总参数法建立了轮轨竖向耦合振动模型;分析了新建地铁车站深基坑开挖过程中既有车站内的轮轨接触荷载对车站结构及其周围土层变形的影响.通过计算分析认为,列车荷载引起的结构变形在允许值的7 %范围以内,引起的地面沉降在允许值的3 %范围以内.     

水泥厂球磨机基础切割拆除控制爆破

介绍了基础切割拆除爆破的实践和经验。同时成功地应用了非电毫秒导爆管雷管孔外多级接力扩大雷管起爆段数的方法。     

阿青水电站沥青心墙坝渗流分析与控制

水电站的渗流计算分析是一项复杂而在设计中又极其重要的工作,很难获得符合实际的渗流分析结果。结合阿青水电站的渗流控制分析,全面阐述了水电站渗流分析中熟悉工程概况和水文地质条件,明确分析任务、概化模型、剖分网格、选取材料参数,确定了计算方案和边界条件,整理分析计算结果,进行方案比较,分析了参数敏感性的方法和过程,认为应做好上述每一个环节,对全面把握工程的渗流性状,进行防渗排水体系的方案选择和优化的重要意义。分析表明,河床最大剖面的渗流量不一定比较低坝高剖面的渗流量大,狭窄河谷心墙堆石坝坝体和坝基总的渗流量,也可能比大坝最大剖面的渗流量与坝轴线长度的乘积大。     

北京某山坡湿陷性土层地基处理可行性分析与建议

北京市密云区某拟建别墅工程,属于山体边坡地基基础工程,任务要求对湿陷性地基土层进行湿陷性消除,并将其地基土承载力特征值提高到fak≥130 kPa。此外,还需要考虑边坡稳定性及其永久性加固问题。对该项目进行了深入分析、研究,并采用概念设计方法,对其进行设计预演,发现该项目存在工序复杂、不易实施、在永久性使用方面存在一定隐患、并具有责任不当等问题。对该地基基础工程进行了重新分析,建议取消地基处理措施,改用嵌岩桩作为拟建物的基础。     

Simple formulations of ground impedance functions for rigid surface foundations

A differential equation is formulated for the dynamic response of ground medium by using a simplified ground model. Applying Galerkin's procedure for weighted residual, this equation leads to a governing equation only at the ground surface. The equation indicates that the ground surface behavior can be computed even further by a simplified model. By solving the governing equation for the boundary conditions along the surface, expressions in simple closed forms are developed for the dynamic response analysis of a massless rigid foundation that rests on the ground surface. Despite their significant simplicity, the developed expressions compute the values very close to those computed by far more complex rigorous solutions. They are found to be capable of capturing the important characteristics of the dynamic ground behavior well.     

Lg amplitude ratios H/Z and station terms in the six eastern provinces of China

Using the data set of about 1 Hz Lg amplitudes from 80 stations in the six eastern provinces of China, the ratios of horizontal to vertical amplitude of Lg waves,H/Z are determined. The mean lg(H/Z)-value is equal to 0.13. For the station bases of soft deposit,granite and sedimentary rock, lg(H/Z)-values average 0.55, 0.04 and 0.10, respectively. For the three kinds of station bases, the station terms of horizontal amplitude,C _h average 0.65, −0.09 and 0.00; that of vertical amplitude,C _z average 0.32, −0.04 and 0.00, respectively. There are the relations betweenC _h ,C _z and lg(H/Z):C _h =0.01+2.10C _z andC _h =−0.15+1.46 lg(H/Z). The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 281–286, 1991. Project sponsored by the Chinese Joint Seismological Science Foundation.