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张集煤矿灰岩顺层定向钻进托压效应及影响因素分析 被引量:7
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作者 豆旭谦 王力 +1 位作者 王毅 徐保龙 《煤矿安全》 CAS 北大核心 2020年第3期168-172,177,共6页
针对张集煤矿坚硬灰岩顺层定向钻进中发现的钻孔孔深与孔口给进压力之间的变化规律,在400~500 m孔深时出现托压现象,运用钻柱弹性送钻理论对托压效应产生的机理进行了分析,能够很好地解释张集煤矿坚硬灰岩顺层定向钻进中发现的规律,托... 针对张集煤矿坚硬灰岩顺层定向钻进中发现的钻孔孔深与孔口给进压力之间的变化规律,在400~500 m孔深时出现托压现象,运用钻柱弹性送钻理论对托压效应产生的机理进行了分析,能够很好地解释张集煤矿坚硬灰岩顺层定向钻进中发现的规律,托压效应的产生主要是受到了钻孔摩阻的影响。在此基础上,对托压效应的影响因素进行了分析,主要影响因素有:地层岩性、曲率和位移、垂深与岩屑、孔深、自重与给进压力,并从减小坚硬岩层滑动定向钻进托压效应影响的角度出发,从减小钻柱与孔壁的摩阻、研发减阻降摩工具和复合钻进方面给出了优化建议。 展开更多
关键词 托压效应 滑动定向钻进 坚硬岩层定向钻进 钻孔摩阻 托压机理
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Study of LDBPs Shaft Skin Friction for Piles in Cohesiove Soils
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作者 石名磊 邓学钧 刘松玉 《Journal of Southeast University(English Edition)》 EI CAS 2002年第2期154-158,共5页
The methodology of predicting pile shaft skin ultimate friction has been studied in a systematic way. In the light of that, the analysis of the pile shaft resistance for bored and cast in situ piles in cohesive soil... The methodology of predicting pile shaft skin ultimate friction has been studied in a systematic way. In the light of that, the analysis of the pile shaft resistance for bored and cast in situ piles in cohesive soils was carried out thoroughly in the basis of field performance data of 10 fully instrumented large diameter bored piles (LDBPs) used as the bridge foundation. The undrained strength index μ in term of cohesive soils was brought forward in allusion to the cohesive soils in the consistence plastic state, and can effectively combine the friction angle and the cohesion of cohesive soils in undrained condition. And that the classical ' α method' was modified much in effect to predict the pile shaft skin friction of LDBPs in cohesive soils. Furthermore, the approach of standard penetration test (SPT) N value used to estimate the pile shaft skin ultimate friction was analyzed, and the calculating formulae were established for LDBPs in clay and silt clay respectively. 展开更多
关键词 large diameter bored piles pile shaft skin friction blow count of standard penetration test
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