一 观测任务 哈尔滨市某地下工程的主体工程是主干道,其施工方法是上下导坑,先拱后墙。从断面上看,洞室呈马蹄状,衬砌是由拱部、侧墙和底部抑拱组成的(图1)。 测试任务是在试验段施工完以后测定衬砌中各测点的钢筋应力和混凝土应力,进而了解整个衬砌的受力状态。测试方法如下:先用钢筋计和周期测定仪测定钢筋的周期,据此换算出钢筋的应力,再用应变计和电阻应变仪测定混凝土的应变,然后换算出混凝土的应力。 A survey mission Harbin City, the main project of an underground project is the main road, the construction method is up and down pilot pit, the first back arch wall. From the section point of view, the cave is horseshoe-shaped, lining is composed of arches, side walls and bottom arching (Figure 1). The test task is to measure the steel bar stress and concrete stress of each measuring point in the lining after the completion of the test section, so as to understand the stress state of the entire lining. The test method is as follows: firstly, the steel bar cycle and the cycle tester are used to measure the steel bar cycle period, thereby calculating the stress of the steel bar, measuring the strain of the concrete with a strain gauge and a resistance strain gauge, and then converting the stress of the concrete.