The mudrocks in the Colombian Andes,particularly those exhibiting low cementation(bonding),are susceptible to degradation when the environmental conditions change,which are challenging issues for engineering works.In this paper,the changes in physico-mechanical properties of mudrocks were monitored in laboratory,and some influential factors on the mechanical competence of geomaterials were studied.The geotechnical characteristics and experimental designs were developed from physical,chemical,mechanical and compositional points of view.In the tests,the techniques such as vapor equilibrium technique(VET)were employed to apply wettingedrying cycles and to control relative humidity(suctioncontrolled)and loadingeunloading cycles through ultrasonic wave velocities technique.The results show that the main failure mechanisms for the laminated mudrocks start on the microscopic scale by fissures coalescence,exhibiting physico-chemical degradation as well;the global geomechanical behavior presents a state between a ductile,like rock,and a fragile,like soil.The obtained results can provide engineering values according to monitoring laboratory set,when compared with in situ conditions. The mudrocks in the Colombian Andes, particularly those exhibiting low cementation (bonding), are susceptible to degradation when the environmental conditions change, which are challenging issues for engineering works. In this paper, the changes in physico-mechanical properties of mudrocks were monitored in laboratory, and some influential factors on the mechanical competence of geomaterials were studied. The geotechnical characteristics and experimental designs were developed from physical, chemical, mechanical and compositional points of view. the tests, the technique such as vapor equilibrium technique (VET) were employed to apply wettingedrying cycles and to control relative humidity (suctioncontrolled) and loadingeunloading cycles through ultrasonic wave velocities technique. The results show that the main failure mechanisms for the laminated mudrocks start on the microscopic scale by fissures coalescence, exhibiting physico-chemical degradation as well the global geomechanical behavior present s a state between a ductile, like rock, and a fragile, like soil. The obtained results can provide engineering values ​​according to monitoring laboratory set, when compared with in situ conditions.