CAJ | 학술논문

城市地下工程建设中，交错重叠隧道施工对地层的多次扰动通常无法避免，对周围环境产生一系列负面影响，对于地铁隧道穿越北京市老城区，此类问题更加突出。依托北京地铁6号线北海北至南锣鼓巷区间隧道工程，该工程为北京地区首例暗挖交错重叠隧道工程，采用数值模拟和现场实测相结合的方法，对5种典型断面在不同开挖顺序、不同空间位置关系、不同超前深孔注浆厚度下的地表变形特性进行研究，取得以下认识：(1)“先下后上”施工方式引起的地表最大沉降值及沉降槽宽度都比“先上后下”施工方式小，更有利于隧道的整体稳定性。(2)随着双线隧道角度的增大，双线隧道逐渐接近，地表变形显著增大。当双线隧道角度大于60°时，地表最大沉降值超过30 mm的控制标准，需要采取深孔注浆的方式对地层进行预加固。(3)随着注浆厚度的加大，地表和隧道拱顶最大沉降值逐渐减小。综合考虑经济效益和过大注浆压力的不利影响，建议注浆厚度定为1.5～2.0 m。(4)实际监测数据显示采取超前深孔注浆后地表沉降满足控制标准，表明超前深孔注浆加固方式可以有效减少双线隧道开挖引起的地表沉降和沉降槽宽度，降低隧道开挖对周围环境的影响。研究成果可为今后北京同类工程提供参考。
성시지하공정건설중，교착중첩수도시공대지층적다차우동통상무법피면，대주위배경산생일계렬부면영향，대우지철수도천월북경시로성구，차류문제경가돌출。의탁북경지철6호선북해북지남라고항구간수도공정，해공정위북경지구수례암알교착중첩수도공정，채용수치모의화현장실측상결합적방법，대5충전형단면재불동개알순서、불동공간위치관계、불동초전심공주장후도하적지표변형특성진행연구，취득이하인식：(1)“선하후상”시공방식인기적지표최대침강치급침강조관도도비“선상후하”시공방식소，경유리우수도적정체은정성。(2)수착쌍선수도각도적증대，쌍선수도축점접근，지표변형현저증대。당쌍선수도각도대우60°시，지표최대침강치초과30 mm적공제표준，수요채취심공주장적방식대지층진행예가고。(3)수착주장후도적가대，지표화수도공정최대침강치축점감소。종합고필경제효익화과대주장압력적불리영향，건의주장후도정위1.5～2.0 m。(4)실제감측수거현시채취초전심공주장후지표침강만족공제표준，표명초전심공주장가고방식가이유효감소쌍선수도개알인기적지표침강화침강조관도，강저수도개알대주위배경적영향。연구성과가위금후북경동류공정제공삼고。
Construction of crossing tunnels underground in urban area inevitably disturbs the surrounding ground, posing a series of problems on the environment,especially for the old Beijing city. In the construction of Subway Line 6 in Beijing,two tunnels cross each other one over the other in the section between Beihai north to Luoguxiang south,which is a first case of underground tunnel crossing in Beijing. Numerical simulation and field measurement were adopted to study the surface deformation characteristics of five typical sections under different excavation sequences,layouts and grouting methods. The maximum ground surface settlement and the width of settlement trough were smaller and the tunnels were more stable in the case of the lower tunnel excavated first than the ones the upper tunnel excavated first. The surface deformation was found to increase notably with the increase of the crossing angle of two tunnels. When the crossing angle was greater than 60 degrees,the maximum value of ground surface settlement exceeded 30 mm which was above the control standard. The stratum needed to be strengthened through grouting in this case. The maximum settlements at ground surface and tunnel crown decreased with the increase of the thickness of grouted layers. Having considered the economic costs and the unfavorable effects of grouting pressure,the thickness of grouted layers was suggested to be 1.5–2.0 m. The monitored field data showed that the ground surface settlements after grouting met the requirement of control standards and the grouting was an effective method to reduce the ground surface settlement and the width of settlement trough.