共查询到19条相似文献,搜索用时 156 毫秒
1.
2.
针对爆破切顶技术受到高瓦斯等特殊环境的限制,提出一种可用于定向切顶的煤岩静态破碎方法。在确定破碎剂基本组成的基础上,利用钢管外测法测出不同组分破碎剂的膨胀压,分析破碎剂水化反应过程中膨胀压的变化规律和各组分对破碎剂膨胀压的影响,确定破碎剂各组分的最佳配比,最后利用所配制的破碎剂进行了C30混凝土试块膨胀致裂试验。结果表明:Ca O是影响膨胀压的主要成分,水泥次之,石膏较小。煤岩静态破碎剂的最佳配比为:Ca O75%、水泥8%、石膏3%、膨润土5%、三聚磷酸钠0.6%、聚羧酸减水剂0.4%、粉煤灰8%。在胀裂试验中,试块逐渐产生细微短小裂纹,随胀裂时间增加开裂宽度和深度缓慢增大,最终试块被胀裂成多块,致裂效果较好,为煤层顶板定向切顶提供了试验基础。 相似文献
3.
4.
5.
静态破碎剂研究现状与展望:献给静态破碎剂问世十周年 总被引:2,自引:1,他引:1
本文综述了十年来国内外静态破碎剂研究与应用概况.着重介绍了最近几年作者在冲孔机理与防治;膨胀力测试技术;构和动静态结合等问题的研究成果与最新进展.对今后的研究提出了一些设想. 相似文献
6.
7.
8.
控制静力破碎剂的反应或等待时间,是施工中很重要的一环。本文介绍了几种缩短静力破碎剂等待时间的有效方法,把该时间从8~12小时缩短至4~5分钟。并考虑实际施工条件,提出静力破碎剂的最佳反应时间为一小时左右。 相似文献
9.
10.
11.
12.
介绍了在山西沁水盆地煤层气压裂时监测到的压裂施工的横向效应,监测使用微地震方法。发现沿人工裂缝法向方向的邻井在施工时出现气量减少、枯竭、出水等反应,沿人工裂缝走向方向的邻井反应滞后。这一发现使笔者注意到煤层气压裂施工的横向挤压作用可能即时影响邻井产量,压裂设计时应该注意到这一反应的不良影响。 相似文献
13.
减缩剂的作用及其机理 总被引:3,自引:1,他引:2
通过对减缩剂作用和机理的研究表明,减缩剂能较大幅度的降低干燥收缩和相对较小的提高塑性收缩抗裂能力,但在一定程度上降低了砂浆的力学性能.从塑性抗拉强度、表面水份蒸发率和孔结构三个角度对减缩剂的作用机理进行了试验分析,结果表明:减缩剂的加入能较显著的降低水溶液的表面张力,同时也降低了砂浆表面的塑性抗拉强度,增大了表面水份蒸发率,它对塑性收缩抗裂的效果取决于对塑性抗拉强度和毛细管收缩应力影响的权重;表面张力试验表明,减缩剂减小干缩的机理主要在于降低了孔溶液的表面张力;从对孔结构的分析表明,减缩剂掺入后增大了孔隙率,并增加了孔径>0.1μm的孔的含量,从而降低了掺减缩剂的砂浆力学性能. 相似文献
14.
针对煤层气特点以及开发过程中压裂工艺技术存在的问题,研究了一项以套管注入、高排量、活性水携砂为主的煤层气清水压裂配套工艺技术。该技术在山西沁水盆地SH煤田现场应用实践了6口井,并获得成功,压后正处于排水阶段,出气效果明显。 相似文献
15.
气温和水温对静态破碎剂膨胀性能影响的试验分析 总被引:1,自引:0,他引:1
为研究水剂比、气温和水温对静态破碎剂膨胀性能的影响,进行了相同条件下5种水剂比和水剂比为0.30时6种气温与3种水温下静态破碎剂的膨胀性能试验,得到了相应条件下的体积膨胀率和拌合物温度-时间曲线。试验结果表明:静态破碎剂膨胀可分为拌合物硬化、裂纹扩展、体积快速膨胀和膨胀速度减慢四个过程。拌合物温度-时间曲线分为温度迅速上升、恒温、继续上升和下降四个阶段。通过对比不同水剂比的体积膨胀率,得出水剂比为0.30时膨胀效果较好;气温为16℃时体积膨胀率较好;采用高水温拌合可加快静态破碎剂的膨胀过程。 相似文献
16.
The present paper is the first of a two-part series reporting an experimental and theoretical study of the fracture of circumferentially notched samples of a commercial aluminium alloy, i.e. Al6082, subjected to tension, torsion and mixed tension/torsion loading. The overall aim of the work was to investigate the use of a particular method of failure prediction, known as the Theory of Critical Distances. This first part reports the experimental data - load-deflection curves and observed material failure modes - and discusses the consequences of these findings for the development of the theory, which is covered in the second part. It was observed that relatively blunt notches loaded in tension failed by a conventional ductile fracture mode similar to plain (unnotched) specimens. However, in tensile specimens containing sharp notches, failure occurred via the initiation, stable propagation and, finally, unstable propagation, of circumferential ring cracks. Under torsional loading, and independent of the notch root radius, static failures of the tested samples always occurred by the formation and stable propagation of ring cracks. Under mixed-mode loading there was a gradual transition between the ductile and brittle modes and between stable and unstable cracking. For all types of loading, it was observed that crack initiation always coincided with peak loading conditions, and that cracks invariably grew on the plane perpendicular to the specimen’s longitudinal axis. 相似文献
17.
18.
阐述了冷净发生炉煤气在蓄热式熔铝炉燃烧系统上使用中注意事项,介绍了冷净发生炉煤气在蓄热式燃烧技术中的应用效果,证明了此项技术在蓄热式熔铝炉上具有良好的推广应用价值。 相似文献
19.
J. E. Callanan S. A. Sullivan R. A. MacDonald 《International Journal of Thermophysics》1987,8(1):133-145
During the development of transferable measurement techniques for the heat capacity of raw coal, it was observed that the atmosphere in sealed sample cells affected the thermal behavior, particularly during the initial measurements. The model which had been used to represent the specific heat of coal did reproduce the results in air but failed to reproduce the deep exotherm of the thermograms obtained in nitrogen. The specific heat of coal has been determined in helium, argon, and carbon monoxide to provide insight into possible modifications to the model. The results of initial and repeat runs in the five different atmospheres and the impact of these results on the modeling are presented and discussed. The agreement between the experimental heat capacity and that predicted by the model, up to 500 K, is excellent and supports Merrick's predictions for the heat capacity of coal. 相似文献