| Geotechnical engineering geological investigation is the premise of construction and design,and is an important means to investigate and study the engineering geology of the construction area.The investigation results realize the reasonable evaluation of the engineering geology of the construction area.Drilling is a common and important engineering task in geotechnical engineering geological investigation.It is the most direct and effective method in geological exploration,and also the key technology for geological exploration in unknown areas.At present,most of the formation information obtained by drilling in China is still mainly recorded by manual,and there are few digital monitoring records for drilling in engineering.Borehole monitoring provides rich,realistic field data that complements and complements traditional manual borehole recording.Through digital drilling,it is beneficial to realize scientific drilling,ensure the authenticity of geotechnical exploration,improve the management level of the site and the quality of investigation.In order to realize real-time supervision of drilling engineering,ensure the authenticity and reliability of formation information of engineering geological exploration,and improve the quality of geotechnical engineering investigation,scientific drilling and digital drilling are carried out by combining big data with geotechnical engineering exploration.The main contents are as follows.(1)The research group jointly developed drilling process monitoring technology,drilling rig can continuously carry out objective,continuous and automatic monitoring records of drilling process.Wireless network communication technology can transmit monitoring data to design and supervision units to realize the automation of geotechnical engineering construction supervision and design change.The instrument can be installed on the drilling rig quickly and lossless.Drilling monitoring has been applied to the exploration project of Luyun Road in Shaoxing.(2)The monitoring parameters include the dynamic load of drill bit,the rotation of drill pipe and the position movement of drill bit.The drilling process is expressed by the change of monitoring parameters with time.The experimental results of drilling process are obtained from Luyun Road exploration project in Shaoxing.It is found that dynamic monitoring of borehole process parameters over time can provide a lot of valuable real data for engineering quality control and geotechnical engineering design inspection.(3)The field application of borehole monitoring is carried out to analyze the parameters of each borehole drilled in soil layer and rock layer.It is found that the fluctuation frequency of the position movement of the rotary power head is larger when the rig is drilling into the soil layer than when the rig is drilling into the rock layer.The oil pressure is more stable when drilling into rock than when drilling into soil.The speed of drill pipe when drilling into soil layer is mainly 300r/min,and that when drilling into rock layer is mainly 600r/min.This distinguishes the working interval where the rig is in drilling state.The power head of the rig gyroscope drops with working time,at the same time,there are certain drilling oil pressure and drill pipe speed,the rig is drilling into the formation.The calculation formula of borehole depth is introduced and the variation of borehole depth with working time is obtained.(4)The borehole parameters are associated with the corresponding borehole formation by depth.The higher the formation strength,the lower the drilling rate.The drilling rate is negatively correlated with the formation strength.The drilling rate of the rig during drilling can reflect the formation heterogeneity.The rotation speed of drill pipe in the process of drilling into soil layer reflects the shear strength distribution of corresponding strata to some extent.Drilling pressure reflects the heterogeneity of soil layer to some extent.Drilling oil pressure further reflects the variation of rock strength with depth on the basis of drill pipe speed and drilling rate.There is a positive correlation between drilling pressure and formation strength. |
