隧道横断面的测量就成为既有隧道改建的关键。

Therefore surveying the tunnel cross section is the key for rebuilding the existing tunnels.

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既有隧道技术改造中，隧道内轮廓是否满足新技术要求，是隧道改建的主要内容。

During the technical reform of the existing tunnels, the main content for rebuilding the tunnel is that the inner outline of the existing tunnel will fulfill the new technical requirements or not.

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结合既有陈家冲隧道改建工程，采用探地雷达和微波湿度测定仪检测了新旧混凝土接缝处结合状态和渗漏情况。

For the Chenjiachong tunnel rebuilding project, the junction and seepage of the fresh and old concrete are tested by using the ground penetrating radar and microwave humidity equipment.

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