摘要
以广西平南至武宣高速公路甘雅隧道项目为例,针对项目处于岩溶强发育的峰丛洼地地貌,山势陡峭、河谷纵横导致常规双向开挖受限的问题,提出一套高速公路隧道单向掘进小导洞出洞施工技术。在小导洞施工前处理方面,依据围岩特征精准选用开挖方式,采用注浆小导管超前支护,根据地层情况灵活调整小导管打入方式;喷射混凝土施工时,严格规范喷射流程,控制喷射角度、距离和顺序;砂浆锚杆安装确保钻孔垂直、锚杆固定稳固,钢筋网铺设保证搭接长度并规范焊接;开挖施工结合机械开挖与微爆破;出洞口施工时,边仰坡开挖自上至下并及时防护。经实际监测,项目洞顶地表无开裂现象,拱顶最大沉降量为18 mm、地表最大沉降量为17.6 mm、周边收敛最大值为30 mm,均在设计允许范围内,说明施工方法合理。
Taking the Ganya Tunnel project on the Pingnan to Wuxuan Expressway in Guangxi as an example,a set of construction techniques for one-way excavation of highway tunnels with small pilot tunnels is proposed to address the problem of the project being located in a karst peak cluster depression terrain,steep mountain terrain,and vertical and horizontal river valleys,which restrict conventional two-way excavation.In terms of pre-treatment before the construction of the small guide tunnel,the excavation method is accurately selected based on the characteristics of the surrounding rock,and grouting small guide pipes are used for advanced support.The method of inserting the small guide pipes is flexibly adjusted according to the geological conditions;Strictly standardize the spraying process,control the spraying angle,distance,and sequence during shotcrete construction;The installation of mortar anchor rods ensures that the drilling holes are vertical,the anchor rods are firmly fixed,and the steel mesh is laid to ensure the overlap length and standardized welding;Excavation construction combined with mechanical excavation and micro blasting;During the construction of the entrance,excavate the slope from top to bottom and provide timely protection.According to actual monitoring,there is no cracking on the surface of the tunnel roof in this project.The maximum settlement of the arch crown is 18 mm,the maximum settlement of the surface is 17.6 mm,and the maximum convergence around is 30 mm,all within the allowable range of the design,indicating that the construction method is reasonable.
作者
杨元军
YANG Yuanjun(Sichuan Road&Bridge(Group)Co.,Ltd.Highway Second Branch,Chengdu,Sichuan 610000,China)
出处
《黑龙江交通科技》
2025年第12期65-68,73,共5页
Communications Science and Technology Heilongjiang
关键词
高速公路
隧道
单向掘进
小导洞
出洞
expressway
unidirectional tunnel excavation
small pilot adit
tunnel exit
