根据可靠性理论基础，阐述了井架可靠度的基本概念。
On basis of the reliability theory, the basic concept of derrick reliability is expounded.
在此基础上着重研究了地基土力学性质对井架动力特性的影响。
Based on this, the effect of foundation soil character on the dynamic behaviour of the mast is emphatically investigated.
在立井井筒建设中，我们在原设计的基础上，对箱形永久钢井架凿井的实际方法作了改进。
This text introduced the practice method of the box permanent steel petroleum derrick shaft sinking in the construction of vertical shaft pit shaft.
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