Multifunctional true triaxial rock drilling test system and method

A method for evaluating an anchoring and grouting reinforcement effect based on drilling parameters, the evaluating method being based on based on a multifunctional true triaxial rock drilling test system, the multifunctional true triaxial rock drilling test including a pressure loading device that applies a confining pressure to a rock test piece placed therein, a drilling rig unit that is arranged at an upper end of the pressure loading device for drilling the rock test piece under pressure, a monitoring control unit that controls the pressure loading device to apply the pressure and controls either of two groups of values of the drilling rig unit, which include a torque and a rotating speed, and a drilling pressure and a displacement, and a hydraulic station that provides power for the pressure loading device, the method performing an indoor drilling test on the rock test piece obtained onsite before and after anchoring and grouting reinforcement, designing an anchoring and grouting reinforcement solution according to a representative value of the equivalent uniaxial compressive strength of the test piece before the anchoring and grouting reinforcement, and determining the reasonableness of the anchoring and grouting reinforcement solution via a guarantee rate λ of the equivalent uniaxial compressive strength after the test piece is reinforced, the method comprising the following specific steps:

• Step A):
• taking onsite fractured rocks in an underground engineering, manufacturing indoor drilling test pieces, and dividing the indoor drilling test pieces into several groups;
• step B):
• taking any group as an example, randomly taking a part of test pieces, implementing an indoor drilling test, recording the drilling parameters of three test pieces, substituting the drilling parameters of each test piece into the optimal regression relational expression of the uniaxial compressive strength and the drilling parameters of preprocessing the collected data, and then establishing the relationship between the processed data and the same-depth rock mechanical properties and rock mass integrity parameters, including an optimal regression relational expression of the uniaxial compressive strength and the drilling parameters, the optimal regression relational expression of a cohesive force and the drilling parameters, the optimal regression relational expression of an inner friction angle and the drilling parameters, the optimal regression relational expression of modulus of elasticity and the drilling parameters, a rock mass integrity parameter RQD value, a torque fracture index QDm and a rotating speed fracture index QDr to obtain the equivalent uniaxial compressive strength of each test piece, and then obtaining a representative value of the equivalent uniaxial compressive strength of the group of fractured rock masses;
• step C):
• comparing the representative value of the equivalent uniaxial compressive strength obtained in the step B) with an expected strength value, designing an anchoring and grouting solution, implementing the same anchoring and grouting reinforcement solution on the rest test pieces in the group, and curing the test pieces under the same conditions;
• step D):
• performing the indoor drilling test on the cured reinforced test piece, and substituting the drilling parameters into the optimal regression relational expression of the uniaxial compressive strength and the drilling parameters of preprocessing the collected data, and then establishing the relationship between the processed data and the same-depth rock mechanical properties and rock mass integrity parameters, including an optimal regression relational expression of the uniaxial compressive strength and the drilling parameters, the optimal regression relational expression of a cohesive force and the drilling parameters, the optimal regression relational expression of an inner friction angle and the drilling parameters, the optimal regression relational expression of modulus of elasticity and the drilling parameters, a rock mass integrity parameter RQD value, a torque fracture index QDm and a rotating speed fracture index QDr to obtain the equivalent uniaxial compressive strength of each test piece;
• and
• step E):
• calculating a guarantee rate of the equivalent uniaxial compressive strength after the reinforcement of the group of test pieces, if the guarantee rate is greater than 95%, judging that the anchoring and grouting reinforcement solution is reasonable, or otherwise, judging that the anchoring and grouting reinforcement solution is unreasonable.