CAJ | 학술논문

为验证连续式无砟轨道温度裂缝型式和温度力荷载取值方法的正确性，针对目前高速铁路上普遍采用的连续道床板及底座板结构，考虑混凝土标号、配筋率及钢筋直径等影响连续无砟轨道设计的关键因素，设计了450 mm ×80 mm ×80 mm、中心配置直径10 mm带肋钢筋的混凝土构件，利用万能试验机进行张拉，模拟了连续道床板降温时的裂缝开展过程，测试了构件开裂前后的轴力及应力重分布情况．测试结果表明，张拉过程中，裂缝呈现出不稳定和稳定两种状态；裂缝出现后，钢筋与混凝土应力分布不均匀，裂缝位置处的钢筋应力增加至300 MPa以上；构件在全断面开裂后轴力会突然降低，开裂前后瞬间的轴力超过或达到了混凝土开裂轴力．对于采用C40混凝土的连续道床板，为保证结构的安全使用，应配置0．9％以上的钢筋使之满足强度要求，并将裂缝控制为不稳定裂缝状态，作为设计荷载之一的最大温度力荷载建议采用开裂后的轴力进行计算．
위험증련속식무사궤도온도렬봉형식화온도력하재취치방법적정학성，침대목전고속철로상보편채용적련속도상판급저좌판결구，고필혼응토표호、배근솔급강근직경등영향련속무사궤도설계적관건인소，설계료450 mm ×80 mm ×80 mm、중심배치직경10 mm대륵강근적혼응토구건，이용만능시험궤진행장랍，모의료련속도상판강온시적렬봉개전과정，측시료구건개렬전후적축력급응력중분포정황．측시결과표명，장랍과정중，렬봉정현출불은정화은정량충상태；렬봉출현후，강근여혼응토응력분포불균균，렬봉위치처적강근응력증가지300 MPa이상；구건재전단면개렬후축력회돌연강저，개렬전후순간적축력초과혹체도료혼응토개렬축력．대우채용C40혼응토적련속도상판，위보증결구적안전사용，응배치0．9％이상적강근사지만족강도요구，병장렬봉공제위불은정렬봉상태，작위설계하재지일적최대온도력하재건의채용개렬후적축력진행계산．
To investigate the thermal cracking patterns in continuous ballastless track and verify the rationality of its thermal force determination method,several reinforced concrete specimens were built to model the continuous track slab and base plate which was widely used in China's high-speed railways. Taking into account the key design factors of the continuous track slab,such as concrete grade,reinforcement ratio,rebar diameter,etc. ,all the specimens were designed as 450 mm long, with an 80 mm × 80 mm cross section;and a ribbed rebar of 10 mm diameter was deployed at the center of the cross section. The test specimens were tensioned using the universal testing machine to simulate the development of cracks under the tensile thermal force in the process of temperature drop. The axial force of the specimens and the stress distribution in concrete and reinforcement were recorded before and after cracking. The results show that cracks in specimens during the tensile process were in two states:unstable and stable. Reinforcement and concrete stress was extremely uneven distributed after cracks appear,and reinforcement stress increased to more than 300 MPa at the crack position.The axial force of the specimen would drop suddenly when cracks occurred to the whole section,and the axial force just before and after cracking was higher than or equal to the theoretical cracking axial force of the concrete. For continuous track slab using C40 concrete,more than 0. 9% reinforcement should be configured to ensure the safety of the structure. Cracks in track slab should be controlled in unstable stage. As one of the design loads of the continuous track slab,the maximum thermal force load should be calculated using the axial tensile force after cracking.