顶管施工坚硬岩层非爆破破岩掘进技术应用

针对复杂地质条件下,顶管施工在遇到岩石、硬土等坚固物块时采用何种方式破岩掘进这一问题,为合理选择破岩方式,根据滇池外海北部水体置换通道改造工程的实际施工情况,分析非爆破掘进技术在小断面水文与工程地质特殊以及周边环境复杂、施工减振(噪)要求高等条件下的适用性。经过对比,最终确定了在无水施工段和有水工作段分别采用静态破碎法、劈裂法作为顶管施工坚硬岩层的非爆破破岩方法。无水段采用采用静态破碎法破岩施工时,根据断面情况提出水平布孔和环形布孔两种方式,相邻孔距为40 cm,排(环)距为50 cm,孔径42 mm;含水段采用劈裂法施工时,全断面采用同静态破碎法工艺相同的环形布孔方式,若断面为复合断面,则应在断面正底部150°范围内钻孔取临空面后,沿临空面向上逐排布孔,孔径100 mm。工程实践表明:静态破碎法在无水工作面岩石掘进效果较好,掘进速率为8.5 m/d;在有水工作面因破碎剂失效,应采用劈裂法破岩,劈裂法破岩速率为10.5 m/d;静态破碎法有利于掘进断面控制,而与静态破碎法相比,劈裂法具有适应性强、掘进速度快等优点。该工程的顺利实施为今后类似条件下小断面顶管硬岩非爆破破岩掘进施工提供了有益的借鉴。

Application of non-blasting rock tunneling technology in hard rock strata for pipe jacking

In view of complex geological conditions，the pipe jacking method is used to break rock and excavate when encountering solid blocks such as rocks and hard soil． In order to reasonably select the rock breaking method，according to the actual practice of the water channel replacement project in the northern part of the Dianchi Lake offshore The construction situation is analyzed，and the applicability of the non-blasting tunneling technology under the special conditions of small section hydrology and engineering geology，complicated surrounding environment，and high requirements for vibration damping ( noise) during construction are analyzed． After comparison，the static crushing method and the splitting method were adopted as the non-blasting rock breaking methods for the construction of the hard rock in the pipe jacking，respectively，in the dry construction section and the water working section． When using the static crushing method for rock breaking construction in the waterless section，two methods of horizontal hole layout and circular hole layout are proposed according to the cross section． The adjacent hole distance is 40 cm，the row ( ring) distance is 50 cm，and the hole diameter is 42 mm． During the split method construction，the whole section adopts the same circular hole layout method as the static crushing method． If the section is a composite section，the hole should be drilled within 150 ° from the bottom of the section and taken along the surface． Arrange holes，100mm． Engineering practice shows that the static crushing method excels the rock excavation effect on the waterless working face，and the excavation rate is 8. 5 m/d． In the water-supply face，the fracture method should be used to break the rock，and the splitting method should be used to break the rock． It is 10. 5 m/d; the static crushing method is beneficial to the cross-section control of the tunneling． Compared with the static crushing method，the splitting method has the advantages of strong adaptability and fast tunneling speed． The smooth implementation of the project provides a useful reference for the non-blasting rock tunneling construction of small-section pipe jacking hard rocks under similar conditions in the future．