Abstract: In-situ direct shear test is an effective method for obtaining the strength parameters.After investigating a set of direct shear apparatus for lab test，a deep hole in-situ direct shear test apparatus was developed，and the structure，working principle and technical advantages of the apparatus are introduced.This device can test shear strength of soft soil and fine sand in deep earth.That the device is directly inserted into the soil by the test cup for sampling can minimize the disturbance of the soil sample.The test cup is equipped with a high precision sensor，which can be used to determine the stress parameters of the soil by means of the vertical and horizontal loading of the soil through the stress sensor.The device is small in size and portable and can automatically achieve data collection.So，it is suitable for the scene with complex environment.The shear strength parameters of sands obtained by this device are approaching to that of the indoor direct shear test.The final results show that the deep hole in-situ direct shear test apparatus can be used to test shear strength of fine sand and soft soil.

Key words: Direct Shear Apparatus, Borehole shear test, In-situ test technology, Loading method, Strength parameter