Research On Integration Of Drilling And Detection Along With Tunneling Of Roadway Supported By Bolting

Nowadays, permanent support of roadway is designed by experience at domestic coal mine, lithology and rock structure of roadway roof can not be detected in time, permanent support design can not be changed according to roof situation, sometimes roof accident occurs because of insufficient support strength, sometimes excessive supporting strength results in waste, excavation speed and efficiency is reduced. Bolt (steel cable) support rate of roadway has reached about80%, constant drilling and bolts installation is required to support newly exposed surrounding rock. Additionally, complex geological conditions, such as methane outburst, composite roof, groundwater, hard rock layers which are difficult to cut, and faults are often encountered during roadway excavation, so drilling, blasting, or detection is required.In view of the above situation, this paper presents integration idea of bolting, drilling, and detection along with roadway excavation. Roadheader is made as a platform which has functions of bolting support and geological drilling. Roadheader is made to combine with integration rig of bolting, drilling, and detection, so safe, quick, and efficient roadway excavation is achieved.Major researches in this paper are as follows:(1) Many kinds of drilling machines used for domestic and foreign roadway excavation are analyzed and compared, integration idea of drilling and detection along with roadway excavation is presented, that is to say, roadheader is made as a platform, integration rig of drilling and detection is designed, integration rig which matches roadheader has multiple functions of bolting, blast-hole drilling, methane releasing drillhole ahead of roadway excavation, lithology detection, and geological drilling, etc.(2) Structure and principle of single-prop hydraulic bolter are analyzed, parameters calculation formulae of hydraulic roof bolter are deduced based on energy detection principle on roof strata drillability, calculation formula of broken work ratio of hydraulic bolter is deduced, uniaxial compressive strength of rocks can be determined by detection of broken work ratio, conclusion is drawn that broken work ratio is mainly determined by three parameters of motor inflow, motor inlet pressure, and inflow of feed cylinder. Measurement method is presented that corresponding thickness and strength of roof layers can be determined through detecting pressure and flow in hydraulic system of hydraulic bolter, so geological basis can be provided to dynamic roof support design.(3) This paper found that there is a step change in firmness coefficient of roadway roof at the rock interface and a pulse change at fracture between separate strata or weak intercalated layer, and there is a step or pulse change of pressure and flow in the hydraulic system of bolt. Dynamic characteristics of the single-prop hydraulic bolter is analyzed, the dynamic characteristics mathematical models of feeding cylinder and motor are built, emphasis is put on dynamic characteristics analysis of feeding cylinder, conclusion is as follows:there is a step change in inlet flow of feeding cylinder at the rock interface or at fracture between separate strata or weak intercalated layer during drilling in the roof strata.(4) The manufacture process of simulation rock strata for test are as follows: typical rock samples are collected from working site of mine, then rock samples are embedded in the concrete, different strength simulation strata are made of yellow mud, concrete, and other materials. Test blocks of different rocks are made and tested to measure unidirectional compressive strength.(5) Test system is built to detect roof strata drillability, flow and pressure transmitters are used to detect pressure and flow in hydraulic system of bolter in drilling process synchronously, continuously, and densely. Data be translated into voltage values and transferred to NI USB-6009data acquisition card. LABVIEW software is made to display the dynamic data and curves of flow and pressure, at the same time the collected data are saved to the computer, layers characteristics such as thickness and strength can be inferred through detecting pressure and flow in hydraulic system of hydraulic bolter during drilling, the mathematical models which are built in this paper are proved to be correct.