为降低地下工程建设对城市地面道路、管线、建（构）筑物的影响，改善管幕法修建的地下通道结构受力，提出一种依托横向预应力的新型地下结构形式——地下束合管幕结构。基于工程需求，针对该束合管幕结构开展1/4结构的足尺试验研究，以探究束合管幕结构在设计工况、超载工况下的变形响应。结果表明： 1）结构变形发展可以分为弹性受力阶段与非线性阶段2个阶段； 2）束合管幕结构的薄弱位置在结构顶部1/4跨的结合缝处，结合缝脱开是关键点，脱开应力为2.106 MPa； 3）束合管幕结构能够承受2倍的设计埋深对应荷载而不出现任何脱开，当结合缝脱开后结构刚度降低60%，同时，在4倍设计埋深对应荷载下，结构未破坏且仍具备承载能力； 4）在超载工况时，预应力应变增量与结构竖向挠度之间几乎呈线性比例关系。
A new type of underground structure, underground
bundled integrate tunnel(UBIT), which relies on transverse
prestress, is proposed to reduce the impact of underground engineering
construction on urban ground roads, pipelines, and buildings (structures) and
improve the stress of underground passage structure. According to the
engineering demands, a fullscale experimental study of
the quarter structure is conducted to investigate the deformation response of
the structure under design and overload conditions. The results reveal the
following: (1) The development of structural deformation can be divided into
elastic stress and nonlinear stages. (2) The weak point is located in the joint
at the structure′s top quarter span, and the separation
stress is 2.106 MPa. (3) The bundled integrate structure can bear twice the
design load without separation, the structure stiffness is reduced by 60% after
the joint separation, and the structure is not damaged and still has bearing
capacity under four times the design load. (4) Under overload conditions, the
relationship between the prestress strain increment and the vertical deflection
of the structure is nearly linear proportional.
