General shear failure in soil occurs when the shearing force applied to the soil exceeds its shear strength, leading to a sudden and catastrophic failure. This type of failure is characterized by several distinct features, one of which is the bulging of the shearing mass of soil.

Here is a detailed explanation of each characteristic of general shear failure:

1. Bulging of shearing mass of soil:
During general shear failure, the soil mass undergoes significant deformation in the form of bulging. This bulging occurs along the failure plane and is caused by the lateral displacement of soil particles. As the shearing force increases, the soil particles are pushed aside, resulting in the expansion and bulging of the soil mass. This bulging is a visible indication of the failure and can be observed on the surface of the soil.

2. Failure is sudden:
General shear failure is an abrupt and rapid process. The failure occurs when the applied shear stress exceeds the shear strength of the soil, leading to a sudden collapse or rupture. This failure is characterized by a rapid loss of strength and stability, often resulting in significant damage or collapse of structures built on or within the soil.

3. Failure is not accompanied by compressibility of soil:
Unlike other modes of failure, such as compressive failure or bearing failure, general shear failure is not accompanied by significant compressibility of the soil. The failure occurs primarily due to the shearing forces acting on the soil mass, rather than compressive forces. As a result, the failure is characterized by lateral movement and deformation, rather than vertical compression.

In conclusion, the characteristic of general shear failure that is mentioned in the given options is the bulging of the shearing mass of soil. This bulging is a visible indication of the failure and occurs due to the lateral displacement of soil particles along the failure plane. The other options, such as compressibility of soil and sudden failure, are not exclusive to general shear failure but may be observed in other types of soil failure as well.