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巷道桩基门式液压支架支护性能研究

Simulation test and numerical analysis of the performance of hydraulic support for pile foundation

  • 摘要: 针对传统巷道门式液压支架因其底梁笨重、占用空间大以及安装和拆除不便等缺点而导致的适用性差的问题。通过理论分析、模型试验和数值模拟等方法开展巷道桩基门式液压支架支护性能研究。在分析总结传统巷道门式液压支架优缺点的基础上,提出一种基于支架−桩基−围岩稳定结构体系的新型巷道液压支架——巷道桩基门式液压支架。建立支架支护性能相似模拟试验模型,以数字散斑相关方法为试验观测手段,对比分析传统巷道门式液压支架与巷道桩基门式液压支架在围岩水平位移、底鼓量和最大剪应变等指标方面的支护性能。构建支架支护性能数值模拟模型,计算不同桩基长度、不同桩基直径和不同桩基角度等条件下巷道围岩位移变化规律,分析巷道桩基门式液压支架支护性能的桩基影响因素。研究结果表明:① 相似模拟试验结果对比分析发现,巷道桩基门式液压支架支护下的巷道围岩下部岩层变形量明显减小,最大水平位移、底鼓量和最大剪应变分别降低了21%、12%和32.6%。② 数值模拟结果显示:巷道桩基门式液压支架支护下,巷道围岩水平位移从巷道侧壁向外扩散递减;桩基对巷道底鼓具有隔断作用,底鼓仅出现在桩间,且底鼓量随着岩层到巷道底面距离的增加而减小;巷道围岩塑性变形呈蝶形分布,主要集中在巷道顶部、两侧及桩间,巷底塑性变形区被桩基隔断。③ 桩基影响因素分析结果表明:增加桩基长度和直径均可降低巷底位移,有效控制底鼓,但桩基超过一定长度后效果减弱,而桩基角度增加会导致巷底位移增大,加剧底鼓,不利于围岩变形控制。

     

    Abstract: In view of the poor applicability of the traditional roadway portal hydraulic support due to its shortcomings such as bulky bottom beam, large space occupation and inconvenient installation and dismantling. Through theoretical analysis, model test, and numerical simulation, the supporting performance of roadway pile foundation portal hydraulic support was studied. Based on analyzing and summarizing the advantages and disadvantages of traditional roadway portal hydraulic supports, a new type of roadway hydraulic support based on the stable structure system of support-pile foundation-surrounding rock was proposed. A simulation test model of support performance was established, and the digital speckle correlation method was used as the observation method to compare and analyze the support performance of traditional portal hydraulic support and pile foundation portal hydraulic support in terms of horizontal displacement of surrounding rock, bottom drum value, and maximum shear strain. A numerical simulation model of support performance was constructed. The displacement of surrounding rock of roadway under different pile lengths, different pile diameters, and different pile foundation angles was calculated, and the influencing factors of roadway pile foundation gantry hydraulic support performance were analyzed. The results show that: ① The comparative analysis of the similar simulation test results shows that the deformation of the lower rock layer of the surrounding rock of the roadway under the support of the roadway pile foundation portal hydraulic support is significantly reduced. The maximum horizontal displacement, bottom drum value, and maximum shear strain are reduced by 21%, 12%, and 32.6%, respectively. ② The numerical simulation results show that the horizontal displacement of the surrounding rock of the roadway diffusion decreases from the sidewall of the roadway under the roadway pile foundation portal hydraulic support. The pile foundation has a partitioning effect on the roadway bottom drum, and the bottom drum only appears between the piles, and the bottom drum value decreases with the increase of the distance from the rock layer to the bottom surface of the roadway. The plastic deformation of the surrounding rock of the roadway is distributed in a butterfly shape, mainly concentrated at the top of the roadway, on both sides, and between the piles, and the plastic deformation area at the bottom of the roadway is separated by the pile foundation. ③ The analysis of the influencing factors indicates that increasing the length and diameter of the pile foundation can reduce displacement at the base of the roadway and effectively control bottom drum effects. However, the benefits of the pile foundation diminish once its length surpasses a certain point. Additionally, increasing the angle of the pile foundation can lead to greater displacement at the roadway bottom and worsen the bottom drum effects, which is detrimental to controlling the deformation of the surrounding rock.

     

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