The rate of bedrock weathering by frost action: Field measurements and a predictive model   总被引：1，自引：0，他引：1  

Norikazu Matsuoka 《地球表面变化过程与地形》1990,15(1):73-90

Shattering rate, surface temperature, moisture content, and the physical and strength properties of bedrock were measured in four rockwall sites of the Japanese Alps. Five-year observations revealed that the bedrock shattering rate was usually much higher in the freeze-thaw period from October to next May than in the frost-free period from June to September. This indicates that frost action is the most important shattering process, although unusual heavy rainstorms in summer are also responsible for the shattering. A combination of some empirical relationships derived from recent laboratory experiments leads to a predictive model of the frost shattering rate. This model shows that the annual shattering rate is dependent on the annual freeze-thaw frequency on the rock surface, and the degree of saturation and tensile strength of the rock masses. The coefficients involved in the model were determined using the field data.  相似文献   

Icequakes and glacier motion: The hans glacier,spitsbergen     

Artur Cichowicz 《Pure and Applied Geophysics》1983,121(1):27-38

The recording of glacier icequakes has been carried out on the Hans glacier, Spitsbergen. The icequakes have been connected with the formation of open cracks. The energy of the main group of icequakes has ranged from 0.01 J to 6 J, their seismic moment being from 0.5 · 10¹⁴ dyne · cm to 26 · 10¹⁴ dyne · cm. The nonelastic volume increase corresponding to each crack has ranged from 0.2 · 10⁻² m³ to 8.8 · 10⁻² m³. The stresses released due to extensional faulting ranged from 25N/m² to 500 N/m²; these values are so small that they suggest an incomplete release of the medium. The contribution into the glacier flow rate of the deformation in the surface glacier layer due to extensional faulting is lower by 2 to 3 orders of magnitude than the total plastic deformation associated with the ice creeping.  相似文献   

Collapse of caves at shallow depth in Gaziantep city center,Turkey: a case study     

Hanifi Canakci 《Environmental Geology》2007,53(4):915-922

This paper focuses on an investigation of the possible causes for the collapse of limestone caves in Gaziantep, Turkey. The city contains a lot of man-made caves, at a shallow depth, of various width and length. These caves were mainly excavated to provide work or storage space. As the city has been growing fast with increased population, many structures were constructed over these caves. Recently, two caves collapsed and five houses were damaged. These caves are all made of limestone and it was observed after the collapse that the limestone was saturated with water due to sewer pipe leakage and surface water. Tests were carried out on the limestone and it was determined that the compressive strength of limestone decreases by about 50% and the tensile strength decreased by about 80% when saturated with water. It was concluded that the reduced strength of the limestone combined with additional loads due to the factors mentioned above seem to be the main reason for these collapses.  相似文献   

柯树北岩体岩石谱系单位的建立及构造环境分析   总被引：1，自引：0，他引：1  

杨永革 《江西地质》2001,15(1):22-28

柯树北岩体为陆壳改造型（S型）花岗岩，具有结构和成分演化序列，运用岩石结构列序法，将其划分为6个单元，归并为1个超单位，按侵入体空间展布形式，岩体地质学，岩石学，构造地球化学等资料，提出了岩浆侵位是受区域拉张应力控制的认识。  相似文献   

对岛状融区房建冻害的几点认识——以沱沱河兵站楼房为例     

黄以职  郭东信 《冰川冻土》1992,(1)

座落在岛状融区中的青藏高原沱沱河兵站楼房,由于跨年度施工,楼房各部位季节冻深和融化速度不一,引起不均匀下沉,致使墙体产生严重裂缝。岛状融区是工程地质环境敏感区。在太阳辐射强烈的青藏高原,现行建筑规范中房屋采暖对冻深的影响系数偏小,建议对北外墙中段和角端应比规范规定系数分别增大0.2和0.3。  相似文献   

论中国东部大型盆地区及邻区地质-地球物理复合尺度解析   总被引：7，自引：3，他引：4  

杨宝俊  张梅生  王璞珺  刘财  孙晓猛  焦新华  单玄龙  孟令顺  刘万崧  许文良  郭华 《地球物理学进展》2002,17(2):317-324

作为对中国东部陆缘地带大型盆地区及邻区地质－地球物理综合研究的部分结果,本文的基本认识：（1）穿过松辽盆地的1孙吴－双辽断裂可能是东倾伯低角度壳内断裂;（2）松辽盆地和渤海湾盆地可能属于“混合型裂谷盆地”;（3）东海盆地台北坳陷处在多期次张性应力场环境中,使在其西部附近产生张性正断层系;（4）欧亚大陆东部新生代区域构造运动总体处于右旋走滑拉张环境,其动力因素包括板块运动和地幔物质运动;（5）研究区莫霍面具有较为复杂的变化;（6）复合尺度研究方法是地质－地球物理综合分析的必要手段。  相似文献   

Lagrangian meshfree particles method (SPH) for large deformation and failure flows of geomaterial using elastic–plastic soil constitutive model     

Ha H. Bui  Ryoichi Fukagawa  Kazunari Sako  Shintaro Ohno 《国际地质力学数值与分析法杂志》2008,32(12):1537-1570

Simulation of large deformation and post‐failure of geomaterial in the framework of smoothed particle hydrodynamics (SPH) are presented in this study. The Drucker–Prager model with associated and non‐associated plastic flow rules is implemented into the SPH code to describe elastic–plastic soil behavior. In contrast to previous work on SPH for solids, where the hydrostatic pressure is often estimated from density by an equation of state, this study proposes to calculate the hydrostatic pressure of soil directly from constitutive models. Results obtained in this paper show that the original SPH method, which has been successfully applied to a vast range of problems, is unable to directly solve elastic–plastic flows of soil because of the so‐called SPH tensile instability. This numerical instability may result in unrealistic fracture and particles clustering in SPH simulation. For non‐cohesive soil, the instability is not serious and can be completely removed by using a tension cracking treatment from soil constitutive model and thereby give realistic soil behavior. However, the serious tensile instability that is found in SPH application for cohesive soil requires a special treatment to overcome this problem. In this paper, an artificial stress method is applied to remove the SPH numerical instability in cohesive soil. A number of numerical tests are carried out to check the capability of SPH in the current application. Numerical results are then compared with experimental and finite element method solutions. The good agreement obtained from these comparisons suggests that SPH can be extended to general geotechnical problems. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Non‐intrusive global/local analysis for the study of fine cracking     

Cécile Oliver‐Leblond  Arnaud Delaplace  Frédéric Ragueneau  Benjamin Richard 《国际地质力学数值与分析法杂志》2013,37(8):973-992

  相似文献   

基于高密度电阻率法的土体干缩裂隙动态发育过程精细监测研究     

章君政唐朝生巩学鹏周启友程青吕超施斌 《岩土力学》2023,(2):392-402

土体在气候作用下发育干缩裂隙是一种常见的自然现象,裂隙的存在会极大弱化土体的工程性质,诱发许多岩土与地质工程问题。为了实时掌握黏性土中干缩裂隙网络的发展状态,提出了一套基于高密度电阻率层析成像技术（ERT）的土体干缩裂隙动态发展过程精细监测方法。分别开展模型试验及原位试验,利用自行研制的测定系统持续采集电流-电位差数据,随后利用自行开发的有限元法电阻率层析成像（FemERT）系统进行数据处理,获取了裂隙网络在不同发育阶段的空间分布特征。结果表明：（1）ERT可以实现土体裂隙发育过程的精细监测,具备监测三维裂隙网络几何形态的能力,裂隙宽度的识别精度达到毫米级,裂隙深度的识别精度达到厘米级;（2）ERT的感度分布特征解释了裂隙发育对于土体电阻率的影响规律,测定电阻值时程曲线因裂隙产生位置的不同而呈现不同的变化规律;（3）反演电阻率及其相对变化率（Rev）可以直观表征裂隙网络在不同阶段的空间几何形态,凸显裂隙动态发育过程对于土体导电性的影响。  相似文献   

红层泥质胶结物干缩裂缝深度与间距预测模型     

陈晓斌  喻昭晟  周雨晴  张家生  钱于 《岩土力学》2022,43(4):868-878

红层泥质胶结物在干燥条件下会因含水率变化产生开裂,裂缝进一步发展贯通最终导致红层泥岩崩解破坏。目前对红层泥岩崩解机制的研究多为定性描述,缺乏定量分析方法。因此,定量研究红层泥质胶结物开裂的产生及扩展对深化红层泥岩崩解理论研究具有重要意义。基于线弹性断裂力学及非饱和土力学,建立了考虑含水率变化的红层泥质胶结物裂缝深度及间距计算公式,并对公式参数敏感性进行了分析。应用CT试验数据对PFC2D数值模型进行了校准,并基于干缩开裂数值试验结果,对裂缝深度及间距计算公式进行了对比验证。结果表明：提出的计算公式能较好地预测红层泥质胶结物的开裂深度及间距,裂缝深度随含水率减小呈先快速增加再缓慢增长的特点。研究成果有助于加深对红层泥岩崩解的量化理论分析,并为预测工程中红层泥岩的开裂程度提供参考。  相似文献