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挤压性软岩隧道大变形灾害及控制措施研究
王正龙
(临沧市公路工程质量监督站,云南临沧 677099)
[摘 要 ] 软岩大变形隧道修建时,由于围岩自稳能力弱,隧道时常发生较大收敛问题。根据云南省云
临高速公路大亮山隧道地质勘察报告,对ZK20+160~ZK20+320段初期支护大范围开裂、仰拱隆起严重等问
题采用有限差分数值方法进行模拟研究。通过对数值模拟结果的分析得出软岩大变形隧道变化规律,并由
此提出相应的设计施工优化措施。研究表明:隧道拱顶沉降与仰拱隆起大,隧道围岩塑性区半径大,符合
高地应力下软岩大变形隧道开挖的物理力学变化特征;将数值模拟二次衬砌拱顶沉降曲线与现场实测拱顶
沉降曲线对比分析,结果表明两者变化规律一致;针对现场初期支护开裂、仰拱隆起与钢拱架扭曲变形等
工程问题并结合数值模拟结果,建议采用双层支护、增设锁脚锚杆和仰拱尽早封闭等优化措施控制隧道变
形开裂问题。
[关键词 ] 软岩隧道;大变形;数值模拟;力学分析;支护优化
[中图分类号] U 451.2 [文献标志码] A [文章编号] 1001 -523X (2023 )07-0109 -05
RESEARCH ON LARGE DEFORMATION CONTROL MEASURES FOR
SQUEEZED BROKEN SOFT ROCK TUNNELS
Wang Zheng-long
[Abstract ] When soft rock large deformation tunnel is constructed, due to the weak self-stabilizing ability of
surrounding rock, the tunnel often has a large convergence problem. Based on the geological survey report of the
Daliangshan tunnel of yunlin expressway in yunnan province, this paper uses the finite difference numerical method
to simulate and study the large-scale cracking of the initial branch of the ZK20+160~ZK20+320 section and the
serious uplift of the inverted arch. Through the analysis of the numerical simulation results, the change law of the
soft rock large deformation tunnel is obtained, and the corresponding design and construction optimization measures
are put forward. The research shows that the tunnel vault settlement and inverted arch uplift are large, and the radius
of the plastic zone of the surrounding rock of the tunnel is large, which is in line with the physical and mechanical
change characteristics of soft rock large deformation tunnel excavation under high ground stress. The comparison
and analysis of the top settlement curves show that the change rules of the two are consistent;in view of the
engineering problems such as initial support cracking, inverted arch uplift and steel arch distortion and deformation,
combined with the numerical simulation results, it is recommended to use double-layer support and additional
locking anchors optimization measures such as early closing of the inverted arch to control the deformation and
cracking of the tunnel.
[ Keywords ] soft rock tunnel; large deformation; numerical simulation; mechanical analysis; support
optimization
常见的软岩地层一般都具有抗剪强度低、高地应
力、遇水易软化分解等特征,在施工过程中极易发生
突泥涌水、隧道超限与垮塌等问题 [1]。十浸高速公路
火车岭隧道,在施工过程中出现掌子面变形与垮塌等
灾害 [2]。
云南省丰收隧道与滇中红层的陈家冲隧道换拱过
程发生了塌方事故 [3]。由于当前山岭隧道的建设大多
以长、深、大的趋势发展,越来越多的隧道需要穿越
大范围的软岩地层。
为了探究高地应力软 岩隧道在开挖、支护过程中
的力学特性及不同支护条件下围岩与二次衬砌结构的
响应,国内外许多学者针对复杂地质构造下高地应力
环境岩性的特殊性进行了相应的研究分析。
在支护形式的选取方面,由于传统刚性支护难以
满足强度要求,让压支护理念被广泛运用于高地应力
软岩隧道 [4–7] ,利用让压单元的有限变形充分释放围
岩压力以达到控制变形与降低造价的目的 [8–10] 。
此外,针对软岩隧道开挖围岩与支护结构力学相
收稿日期 :2023–02–15
基金项目: 云南省交通运输厅科技项目(云交科教便 [2021]7 号)
作者简介 :王正龙(1990–),男,云南临沧人,工程师,主要研
究方向为交通工程、桥梁、隧道领域的质量检测。
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应方面,杜伟 [11] 对倾斜岩层巷道围岩破坏过程做了有
限差分数值模拟分析,系统研究了不同工况下的破坏
过程与巷道围岩的力学响应对巷道围岩的应力、 位移
与塑性区大小等的影响。
潘建峰等 [12] 对大变形软岩巷道支护难、沉降大等
问题采用FLAC数值模拟软件对不同支护条件下围岩
的变形特征进行探讨并提出了联合支护方案。
赵庆涛等 [13
挤压性软岩隧道大变形灾害及控制措施研究(论文).pdf