Discussion of “experiment and statistical assessment on piping failures in soils with different gradations”

Internal stability assessment methods, such as Kezdi and Kenney and Lau, have some degree of uncertainty and they do not take the effect of soil density in consideration. Analysis show that the internal stability of some granular soils could be stable, transition state, or unstable based on the relative density. All these factors could affect the accuracy of statistical analysis based on the assessment of these methods.     

Closure to discussion of “experiment and statistical assessment on piping failures in soils with different gradations”

This paper responds to the comments from two discussions. The comments related to the uncertainties in the internal stability criteria and the determination of input soil property for prediction models, which affect the accuracy of predicting critical hydraulic gradient, are addressed and discussed.     

青岛台站重力固体潮和海潮负荷特征研究

选取青岛台站2012-01~2013-02 gPhone重力仪连续观测资料进行预处理和调和分析,获得其重力潮汐参数,并选取8个全球海潮模型对O1、K1和M2潮波进行海潮负荷改正。结果表明：1）8个主要潮波调和分析的振幅因子标准差均在2.6%之内,与理论潮汐模型值的差异也在3.0%之内;2）利用海潮模型对O1、K1和M2潮波进行改正能有效地降低残差矢量,观测残差负荷改正的有效性大致分布在30%~75%,全球海潮模型对青岛台站主要潮波的海潮负荷改正差别不大。     

核废料贮存裂隙岩体耦合分析研究综述

在核废料地质处置过程中,涉及到热液力三种影响因素及其耦合问题,拟对国内外就这一研究方面的进展和现状作一介绍和评述,并对进一步研究核废料贮存围岩全耦合问题提出分析方法。     

关于注水地震研究的几个问题

本文认为注水地震是相当复杂的。将注水只看成诱发因素,或将与注水相关的地震都看成构造地震是片面的。对注水过程的微震研究表明,注水可以直接造成地震。对油田地震的研究表明,大量采油造成地下介质的亏空同样可能造成地震。对其它一些地下矿藏的采掘也有类似的情况。错误地把与注水有关的地震都看成是注水诱发的构造地震,将导致对地壳构造活动特点的错误估计。     

岩层阻水性能与其结构成分、组合形式的关系

根据室内水力压裂试验的结果,通过分析裂痕端部应力强度因子的变化情况,研究了不同结构成分岩层的各自阻抗水压致裂的能力,分析了岩性变化、交界面性质对水压致裂裂隙扩展的影响,提出了阻抗水压致裂裂隙扩展和防止承压水导升的较优岩层组合形式。      

基于类海啸波型的岛礁水动力特性数值模拟研究

基于非静压单相流模型NHWAVE建立了高精度二维数值波浪水槽,采用日本2011年实测真实海啸波型系统研究了海啸波在岛礁上传播变形的规律,并且分析了波高、礁坪淹没水深和礁前斜坡坡度等因素对孤立波和真实海啸传播变形的影响。结果表明,相比孤立波,类海啸波的波长明显大于孤立波波长,在测点处引起的水面变化持续时间更长,同等波高情况下真实海啸波型比孤立波能够携带更多的能量,与岛礁的相互作用也更为复杂,在礁坪上形成的淹没水深约为孤立波的两倍。礁前斜坡坡度和礁坪淹没水深均对类海啸波的反射和透射系数有显著影响。随着礁前斜坡坡度的增加,反射系数和透射系数均逐渐增加。随着礁坪淹没水深的增加,反射系数逐渐减小,而透射系数逐渐增大。但是,反射系数和透射系数均随着入射波高的增加而逐渐减小。     

Seismic energy dissipation under variable amplitude loading for rectangular RC members in flexure

The energy dissipation characteristics of reinforced concrete members that exhibit both strength and stiffness deterioration under imposed displacement reversals were investigated. To do this, 24 symmetrically reinforced concrete rectangular specimens were tested under stable variable and random variable amplitude inelastic displacement cycles. Stable variable amplitude tests were employed to determine the low‐cycle fatigue behavior of specimens where the loading sequence was the major variable. A 2‐parameter fatigue model was developed in order to express the variation of the dissipated energy in displacement cycles with the cumulative hysteretic energy. This model was then used to predict the energy dissipation of test specimens subjected to random variable amplitude displacement cycles simulating severe seismic excitations. It has been demonstrated that the remaining energy dissipation capacity for the next displacement cycle was dependent on the relative relationship between the maximal displacement cycle and the energy dissipated along the completed displacement path. The plastic energy dissipation capacity of reinforced concrete members is both displacement path dependent and cumulative hysteretic energy dependent.     

Incorporating spatially heterogeneous infiltration capacity into hydrologic models with applications for simulating post‐wildfire debris flow initiation

Soils in post‐wildfire environments are often characterized by a low infiltration capacity with a high degree of spatial heterogeneity relative to unburned areas. Debris flows are frequently initiated by run‐off in recently burned steeplands, making it critical to develop and test methods for incorporating spatial variability in infiltration capacity into hydrologic models. We use Monte Carlo simulations of run‐off generation over a soil with a spatially heterogenous saturated hydraulic conductivity (K_s) to derive an expression for an aerially averaged saturated hydraulic conductivity ( ) that depends on the rainfall rate, the statistical properties of K_s, and the spatial correlation length scale associated with K_s. The proposed method for determining is tested by simulating run‐off on synthetic topography over a wide range of spatial scales. Results provide a simplified expression for an effective saturated hydraulic conductivity that can be used to relate a distribution of small‐scale K_s measurements to infiltration and run‐off generation over larger spatial scales. Finally, we use a hydrologic model based on to simulate run‐off and debris flow initiation at a recently burned catchment in the Santa Ana Mountains, CA, USA, and compare results to those obtained using an infiltration model based on the Soil Conservation Service Curve Number.     

区域性节理控制的反倾岩质斜坡水力劈裂破坏机制——以北京“8·11”大安山岩质崩塌为例

以2018年"8·11"大安山反倾岩质崩塌为研究对象,通过对大安山地区区域性节理、崩塌及斜坡结构、危岩体变形特征等进行调查研究,运用水力劈裂理论,剖析大安山崩塌机制。研究结果表明:在区域性节理和差异性风化共同作用下,大安山地区发育大量高20~50 m高陡反倾岩质斜坡,为崩塌灾害发生提供充分条件;同时,节理裂隙网络与强硬岩层的空间组合为降雨入渗、运移、储藏提供了良好的地质条件,当遭遇降雨时,雨水沿岩体裂隙渗流并充满裂隙,在降雨停止后短期内,裂隙受高水头作用仍发生水力劈裂,致使裂隙发生扩展贯通,并最终导致危岩体失稳崩塌。