摘要
针对隧道掘进中遇到的凝灰质砂岩地层非均质性问题,提出了一种基于动力冲击的聚能切缝破岩新技术。采用自主研发的岩土体动态冲击力学试验系统,在尺寸为∅100 mm×50 mm的圆柱形凝灰质砂岩试样一端粘贴厚度为10 mm的聚氨酯垫片,在垫片上沿径向分别开设直径为3、6、9 mm的孔洞,共嵌入6根对应直径的相同聚能钉。设置了冲击气压为0.35~0.65 MPa的7组试验,考察了不同冲击能量和钉径对定向切缝破岩效果的影响。结果表明:随着冲击气压增加,试样的峰值应力和能量吸收显著增大,而裂缝贯通程度增强,破裂模式由沿晶破坏为主向穿晶破坏为主转变。3 mm聚能钉易因局部压溃而无法形成有效贯通切缝;9 mm聚能钉在高气压下促使岩石产生块状或粉碎破裂;6 mm聚能钉在多种气压下均表现出稳定连续的定向切缝特征,形成较多穿晶裂纹,展现出优异的能量利用效率。扫描电镜分析结果验证了冲击应变率效应:低应变率(低冲击力)下裂纹多沿晶界扩展,高应变率下裂纹趋于穿晶扩展。该技术充分利用了冲击动力学中压缩-反射-张应力闭合链的破裂机制,实现了无炸药、无液体介质的可控定向破岩。合理匹配冲击参数和聚能钉直径,可在深埋隧道非均质岩层中高效诱导裂缝沿预定方向扩展,为复杂地质条件下隧道掘进中的超欠挖控制提供新思路和参考。
This study addresses the challenge of excavating through heterogeneous tuffaceous sandstone formations in tunnel construction by proposing a novel energy-gathering slotting rock-breaking technique based on dynamic impact.Using self-developed geotechnical dynamic impact testing system,cylindrical tuffaceous sandstone specimens(∅100 mm×50 mm)were prepared with 10 mm thick polyurethane pads adhered to one end.Radially arranged holes of 3,6,and 9 mm in diameter were drilled into the pads,each fitted with six corresponding energy-gathering nails.Seven groups of tests were conducted under impact air pressures ranging from 0.35 MPa to 0.65 MPa to investigate the effects of varying impact energy and nail diameter on directional rock fracturing performance.The results show that as the impact pressure increases,the peak stress and energy absorption of the specimens rise significantly,with fracture patterns transitioning from primarily intergranular to transgranular cracking.The 3 mm nails were prone to local crushing and failed to produce effective through-cutting cracks,while the 9 mm nails caused blocky or pulverized failure under high pressure.In contrast,the 6 mm nails consistently induced stable,continuous,and directional fractures under various pressures,producing more transgranular cracks,and demonstrating excellent energy utilization efficiency.Scanning electron microscopy confirmed the strain-rate effect of impact:cracks were predominantly intergranular under low strain rates(low impact forces),and became transgranular under high strain rates.This technique leverages the compressive-reflective-tensile stress chain mechanism inherent in dynamic fracture mechanics to achieve controlled,directional rock breaking without explosives or liquid media.By properly matching impact parameters and nail diameters,this method can efficiently guide crack propagation along predetermined paths in deep,heterogeneous rock masses,offering a promising strategy for controlling over-and under-excavation in complex geological tunneling conditions.
作者
王伟
程明峰
罗鑫
王金宝
邹宝平
曹春晖
WANG Wei;CHENG Mingfeng;LUO Xin;WANG Jinbao;ZOU Baoping;CAO Chunhui(Zhejiang Quli Railway Co.,Ltd.,Lishui 323000,Zhejiang,China;School of Civil Engineering and Architecture,Zhejiang University of Science and Technology,Hangzhou 310023,Zhejiang,China)
出处
《高压物理学报》
北大核心
2026年第3期117-130,共14页
Chinese Journal of High Pressure Physics
基金
国家自然科学基金(42477185)。
关键词
凝灰质砂岩
动力冲击
聚能切缝
聚能钉
能量吸收
tuffaceous sandstone
dynamic impact
energy-gathered cutting
energy-gathering nail
energy absorption
