轨道交通工程裂缝与渗漏机理及其应对措施

Mechanism and Countermeasures of Structural Cracks and Leakage in Urban Rail Transit

研究目的:针对我国城市轨道交通地下工程广泛存在的裂缝与渗漏现象,从裂缝机理方面揭示各类裂缝与渗漏现象产生的原因,揭示裂缝对构件承载力与耐久性的影响,基于后浇带设计理念与高延性混凝土特性,提出结构与防水合二为一的新型接缝处理思路,解决地下工程广泛存在的裂缝与渗漏问题,提出耐久性好、强度高的加固材料,从既有工程维保角度出发,提出可以满足限界要求的结构加固方法,以期提高地下工程的受力稳定性与长期耐久性。研究结论:(1)根据裂缝产生机理将地下工程裂缝归纳为早期构造性裂缝与后期结构性裂缝两大类;(2)相对于早期构造性裂缝,结构性裂缝的危害更大,对管片衬砌而言,当结构性裂缝深度达到30 mm左右时,构件承载力将降低20%左右,同时加速了混凝土的老化进程,降低了耐久性;(3)利用纤维高延性混凝土的韧性,基于后浇带设计理念,提出了结构与防水相结合的高延性混凝土接缝处理措施,解决了混凝土浇筑早期的构造性接缝,使得整体结构刚柔结合,有效减小了使用阶段结构性裂缝几率;(4)提出了耐久性好、强度与密度可调、适应性强的非水反应高聚物注浆材料;(5)提出了基于高延性混凝土的嵌锁柱新型叠合构件,满足了限界空间有限情况下的既有构件加固需要;(6)本研究成果可为地下工程结构设计、补强与防渗堵漏方面提供参考。

Research purposes:As for the widely existed structural cracks and leakage in underground engineering of urban rail transit,the mechanism of all cracks and leakage is revealed,and the influences on structural bearing capacity and durability are made clear.Based on the concept of late poured band and the characteristics of high ductility concrete,the new joint treatment with the combination of structure and waterproof is put forward to solve all the kinds of cracks and leakage,and the reinforcement material with good durability and high strength is proposed.For the maintenance perspective of existing engineering,the structural reinforcement method that can meet the requirement of boundary condition for underground engineering is put forward,and the load stability and long-term durability can be improved.Research conclusions:(1)Based on the induced mechanism,cracks in underground engineering can be concluded as constructive cracks and structural cracks.(2)Compared with constructive cracks,the structural cracks are more harmful.As for lining structure,when the crack is near 30 mm depth,20%of load capacity will be reduced relevantly.And the aging process of concrete is accelerated,the durability is reduced correspondingly.(3)Based on the toughness of high ductility concrete and the design concept of late poured band,the new joint treatment method of high ductility concrete with the combination of structure and waterproof is put forward.The constructive cracks can be well solved,the whole structure with the combination of rigid and flexible can be realized,and the probability of structural cracks in the use stage can be effectively reduced.(4)The polymer material based on non-aqueous reactive is put forward,and it is characterized by good durability,adjustable strengthen and density,and strong adaptability.(5)The new type of superimposed component with lock column is put forward which can meet the reinforcement needs of existing components in the case of limited space.(6)The research results can provide reference for structure design,structure reinforcement and seepage prevention of underground engineering.