Sampling schemes for hillslope hydrologic processes and stability analysis based on cross-correlation analysis
Sampling schemes for hillslope hydrologic processes and stability analysis based on cross-correlation analysis
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基于互相关分析的山坡水文过程采样方案及稳定性分析
DOI：
10.1002/hyp.11101
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发表时间：
2017
影响因子：
3.2
通讯作者：
Zha Yuan-Yuan
中科院分区：
文献类型：
--
作者：
Cai Jing-Sen;Yan E-Chuan;Yeh Tian-Chyi Jim;Zha Yuan-Yuan
成本效益的采样策略，以了解水文过程中的山坡是必不可少的估计山坡渗流和边坡稳定性的评价。本文的目的是（a）引入随机互相关分析的山坡水文过程和稳定性调查和（B）开发一个具有成本效益的采样策略，以减少孔隙水压力的不确定性在我们感兴趣的区域。首先介绍了土壤水力特性空间变异性随机表示的概念。然后，我们开发了一个一阶分析方法，以确定时空分布的孔隙水压力水头（P）方差（无条件方差或不确定性），由于空间变异性的饱和导水率（K-s）在一个半饱和的山坡在降雨过程中。随后，互相关分析，它量化的空间相关性P在一个给定的位置和K-s在任何一个部分的山坡下的瞬态入渗事件。之后，我们制定了一个一阶近似的剩余P方差（条件方差或不确定性），由于包含K-s测量。所开发的方法适用于合成，异质性，二维山坡调查的有效性，几个K-S抽样方案。调查结果表明，钻孔和采样位置应设置在一个相关尺度的间隔。它们应该分布在一个覆盖多个相关尺度的区域上，而不是聚集在最大的互相关区域或预测不确定性很大的区域（我们的兴趣和关注）。此外，结果表明，增加采样密度是有用的，但效率低下。山坡的分层结构减少了所需的钻孔和样本数量。最后，提出了一种基于互相关的边坡稳定性研究的抽样策略，该策略可以最大限度地减小临界点P的预测不确定性。
Cost-effective sampling strategies to understand hydrologic processes in a hillslope are essential to the estimation of hillslope seepage and to the evaluation of slope stability. The objectives of this paper are (a) to introduce a stochastic cross-correlation analysis to hillslope hydrologic processes and stability investigation and (b) to develop a cost-effective sampling strategy to reduce the pore-water pressure uncertainty at the region of our interest. The concept of stochastic representation of spatial variabilities of soil hydraulic properties is introduced first. We then develop a first-order analysis method to determine spatiotemporal distribution of pore-water pressure head (P) variance (unconditional variance or uncertainty) due to spatial variability of saturated hydraulic conductivity (K-s) in a variably saturated hillslope during rainfall. Subsequently, a cross-correlation analysis is presented, which quantifies the spatial correlation between P at a given location and K-s at any part of a hillslope under a transient infiltration event. We afterward formulate a first-order approximation of residual P variance (conditional variance or uncertainty) due to inclusions of K-s measurements. The developed methodology is applied to synthetic, heterogeneous, two-dimensional hillslopes to investigate the effectiveness of several K-s sampling schemes. Results of this investigation show that boreholes and sampling locations should be placed at an interval of one correlation scale. They should be distributed over an area covering several correlation scales, rather than clustered together at the largest cross-correlation region or at regions where prediction uncertainty is large (where our interest and concern are). Further, the results demonstrate that increasing the sampling density is useful but inefficient. Layering structures of hillslopes reduce the number of boreholes and samples required. At last, a cost-effective sampling strategy for study of slope stability based on cross-correlation is suggested, which minimizes the prediction uncertainty of P at critical locations.