西部富水软岩地层冻结温度场演化实测分析

为掌握西部富水软岩地层深基岩立井冻结温度场发展演化规律,对鄂尔多斯某矿风井冻结工程实施了信息化监测,获得了该矿区地层冻结特征,并分析了不同岩性地层温度在冻结不同阶段的变化规律。结果表明,西部富水软岩的优异导热特性使得积极冻结期短,降温效率高;且后续维护冻结期受施工影响,温升大。不同岩性地层温度发展受原始地温、地下水流方向、钻孔偏斜等多种因素影响。具体表现为越深位置岩层在积极冻结期,降温效率越低,进入负温时间越长;且在维护冻结期,不同测温孔间温度差异越明显。西部富水软岩地层冻结施工过程中,应密切关注较深位置地下水上游方向附近冻结壁的发展状况,避免发生安全事故。

西部地区立井井壁-围岩共同承载理论与井壁设计原则

随着西部地区立井井筒建设需求的日益增多,基于西部地层特性的立井井壁设计理论与方法是保证井筒工程经济性和安全性的重要前提。通过研究西部井筒地质特性与围岩特性,获得了基于“弹-黏-脆-塑性”蠕变围岩卸载解析解的数值计算方法,并得到了围岩应力-应变空间分布与时间演化规律。考虑复合井壁结构特征,提出了井壁-围岩共同承载理论和井壁设计原则,获得了不同井筒工程特征、围岩特征、井壁特征等因素对相互作用的井壁受力影响规律,为西部立井井壁优化设计提供了理论基础。

Coefficient of earth pressure at rest for normal,consolidated soils

In this study consecutive consolidated isotropically drained triaxial tests for the coefficient of earth pressure at rest(K_0) were carried out to investigate its rules of evolution as well as its strength characteristics for normal,consolidated saturated silt under high pressure.The tests results indicate that:1) for normal,consolidated saturated silt,K_0 values increase as the consolidation stress increases at high pressure levels,while the nonlinear characteristics of K_0 are inconspicuous compared to cohesive soils;2) the Jaky and Roscoe equations,used to calculate K_0,are only suitable for certain soils,but cannot represent these values for normal, consolidated saturated silt due to the variation in bilinear strength at high pressure;and 3) there are close relations between the nonlinear characteristics of K_0 and the void ratio,measured in the tests.Both share the same functional form while under pressure. Based on our experimental results,we developed an empirical linear model to interpret the rules of nonlinear variation for the coefficient of earth pressure at rest.

深厚表土井壁附加应变在线监测系统与工程应用

本文构建了深厚表土井壁附加应变在线监测系统,系统从硬件层面上优化为数据采集模块直接下井就近采集传感器数据,软件层面上通过无线传输实现了远程云服务器实时大数据处理与分析。基于该在线监测系统,对李楼煤业副井井筒附加应变进行了实测,获得了其长期演变一般规律,即深厚表土中井壁附加应变受季节温度和竖直附加力综合作用,整体呈正弦曲线叠加负斜率直线函数变化,最大应变累积速率定量数值达-0.2464με/d。