Electric thawing of permafrost foundation beds using horizontal current-conducting layers (HCL)

Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 10–13, Jamuary–February, 1991.     

Compressibility of sandy permafrost during thawing

Conclusions 1. The compressibility of sandy permafrost deep deposits with a medium texture density is, as a rule, close to the compressibility of similar thawed deposits.2. The degree of saturation of frozen sandy soils may serve as an indicator of their compressibility during thawing. When G_f<0.91, the compressibility of frozen sands during thawing is equal to the compressibility of similar thawed soils.3. The compressibility of frozen sandy deposits during thawing, which increased as compared with ordinary thawed sands, should be expected in zones adjacent to the roof of soils with a low permeability.4. The refinement of the method and the high quality of the testing of thawing soils increases significantly the technicoeconomic effectiveness of construction on permanently frozen sandy soils, making it possible to reduce the volume of special measures taken to ensure the stability of buildings and structures, or eliminate them entirely.All-Union Scientific-Research Institute of Foundations and Underground Structures. Northern Branch of the All-Union Scientific-Research Institute of Foundations and Underground Structures. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 20–22, May–June, 1988.     

冻融循环条件下土的融沉性质试验研究

多年冻土地区路基病害主要由冻土土体在季节变化条件下的冻融循环造成的。因此,本文结合青藏铁路清水河、北麓河试验段土质条件,通过室内试验探讨和研究了不同土质在不同含水率、密实度、荷载条件下,反复冻融过程中的融沉特性。并探讨了循环融沉系数与融沉系数的关系及表达式,为进一步深化对融沉特性的认识提供了参考。     

Use of seasonally freezing heave-prone soils as beds for underground structures

Results are cited for field investigations of the deformation of underground tunnels constructed in vigorously heaving soils in Omsk. A design scheme is proposed for tunnels subject to nonuniform frost heaving over the length of their foundation beds. The feasibility and economy of using backfill as foundation beds during installation of underground structures are demonstrated.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 26–29, January–February, 2005.     

薄膜结构附加质量的计算方法

薄膜结构与风环境之间存在着较强的耦合作用，并且这种耦合作用往往是薄膜结构动力稳定的决定性影响因素．附加质量是表征这种耦合作用的主要参数之一．本文以薄膜结构与风环境的静力耦合模型为基础，给出了附加质量的三种计算方法：势流理论法、简化流体力学模型法以及基于声学理论的有限元法，并对它们的适用范围进行了初步分析，为薄膜结构的风致动力效应研究奠定了基础．     

冻融对混凝土碳化的影响

为研究冻融对混凝土碳化的影响,对4种不同配合比混凝土先后进行冻融循环和加速碳化,测定其CaCO3含量,并采用Boltzmann函数拟合碳化深度值.结果表明,冻融作为混凝土损伤的动力源,加速碳化进程,循环次数越多,碳化后CaCO3含量和相应的碳化深度越大;在冻融和高浓度CO2环境下,粉煤灰的掺入增加混凝土碳化量,对混凝土结构不利.     

冻融作用下特定污染物的清洗试验研究

抽出处理法是目前修复土壤污染常用的方法之一,为了解决抽出处理法中对渗透性差的土中污染物和低浓度污染物效率低的问题,利用土体冻结过程中在一定的温度梯度和水分条件下未冻土侧水分(溶质)向冻结锋面迁移和冻融作用导致渗透性增强的特性,开展了基础试验。试验将混有模拟污染物NaCl溶液的粘土作为研究对象,结合传统的抽出处理法,实施了单向冻融试验和污染物清洗模型试验,探索了利用冻融现象清洗污染土壤的可行性。结果表明,冻融作用有助于提高污染物的抽出效率。     

冻融作用下地基土水分迁移试验研究

为研究季节性冻融区地基土水分迁移的规律,对不同初始含水量以及温度梯度作用下的重塑土进行了冻融试验,试验结果表明:随着初始含水量的增加,土样水分迁移更加明显;温度梯度越大,土样冻结速率越大,水分聚集层越靠近暖端。     

Limiting-state design of permafrost beds for global warming

The stability of permafrost beds is examined from positions of reliability theory. A method is proposed for calculation of the safety factor; use of this method makes it possible to account for random variations in air temperature and global warming of the climate in the limiting-state design of beds. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 21–23, September–October, 1997.     

冻融作用对原状黄土抗剪强度的影响规律

以西宁市某区域内原状黄土为研究对象,设计封闭系统下的三向慢速冻结试验、恒温恒湿的融化试验以及三轴剪切试验。基于土的莫尔库伦强度理论,利用抗剪强度包线求解黏聚力和内摩擦角,研究不同冻融温度梯度下抗剪强度指标的变化规律。结果表明:随着温度梯度增大,黏聚力衰减速度显著,衰减为极小值时的最不利冻融温度梯度为-15～15℃;冻融黄土的黏聚力与冷端温度、融化温度有关;较低含水率和较小冷端温度耦合作用或较高含水率和较大冷端温度耦合作用时,与冷端温度相比,融化温度为主导影响因素。随着冷端温度的增大,不同含水率试样的黏聚力降低幅度呈先减小、后增大的规律,最不利的含水率为18.34%。内摩擦角呈现出不规律性波动,变化幅度约为0～14°。由试验数据拟合出黏聚力随冷端温度和含水率变化规律的计算式,经试验验证,计算式能较好地描述其变化特性。