Study on Supporting Protection of Tunnel Opening near a Rock Layer under Elastic Deformation of Surrounding Rock

Table 1

Contents of required test items.

Serial number	Work content	Measuring instrument	Measurement accuracy
1	Observation inside and outside the cave	Field observation
2	Vault sinking measurement	Electronic level, steel hanging ruler, indium steel ruler, total station	0.01 mm
3	Peripheral displacement measurement	Convergence meter, total station	0.01 mm
4	Ground settlement measurement	Electronic level, indium steel ruler, total station	0.01 mm