Underground engineering construction in this type of formation is different from a single soft formation and hard formation. Due to the large difference in stiffness between the soft formation and the hard formation, the drilling and cutting speed and the reaction force of the drilling and 
cutting tool on different soft and hard formations are not equal.  , so that the drillability of soft and hard formations is different from that of single soft and hard formations, resulting in the drilling and cutting force of the drilling construction surface is more difficult to control than in single soft and hard formations, so it often occurs in the process of underground engineering construction  Quality accidents such as 
pile position deviation, loose 
pile concrete segregation, cracks, mud inclusions, surface settlement, 
underground pipeline damage, and surface buildings tilting or collapsing
Existing drilling devices for soft and hard formation mainly include super large 
diameter shield cutter head, shield scraper, 
shield machine tool, PDC bit, geophysical scour bit, etc.  The cutting device is mainly rock-socketed pile air-pressure-controlled cutting, but shield drilling devices such as super-large-
diameter shield cutterhead, shield scraper, 
shield machine tool, etc. are bulky and expensive.  Drilling devices such as engineering survey drilling devices have 
small hole diameters, blade distribution angles and cutter distribution settings are unreasonable, and when rock-socketed piles are controlled by air pressure to 
cut soft and hard strata, the cutting force of the cutting surface cannot change in real time with the stratum.  needs improvement
Therefore, the existing drilling and cutting devices for the construction of soft and hard formations are mainly single drilling devices and cutting devices, lacking a composite drilling and cutting device with both drilling and cutting functions.
[0003] 
Chinese patent CN106907158A is a super-large 
diameter shield drilling and cutting system for soft and hard uneven strata, including large cutterhead, medium cutterhead, small cutterhead, spokes, panels, hobs, cutters, leading cutters, center cutters,  Stirring rods, reducers, hydraulic motors, 
power transmission devices, shields, and screw excavation devices, but the 
layout of the drilling and cutting system is that the multi-layer cutter head space is staggered, and the cost is expensive. When the cutter head encounters soft and hard strata for drilling construction  However, due to the limitation of the overall structure of the front cutter head of the 
shield machine, the shield 
machine can only be driven into soft and hard areas by controlling various cutter heads, and it is difficult to effectively control the drilling and cutting forces of the corresponding cutting surfaces in different 
layers of soft and hard 
layers.  , at the same time it cannot cut hard formations in soft and hard formations
[0004] 
Chinese patent CN206495679U is a kind of shield scraper used in soft and hard uneven formations.  There is a hard 
alloy on the back of the body, and a wear-resistant 
alloy layer on the cutting edge of the cutter body. However, the shield scraper is mainly to enhance its 
impact resistance in bad formations, and the cost is high, so it cannot guarantee the protection of soft and hard formations.  The accuracy of the main structure during construction cannot be used for drilling and cutting rock and soil in soft and hard formations
[0005] 
Chinese patent CN204552753U is a shield 
machine tool suitable for soft and hard uneven strata, including multiple tool combinations installed on the cutter head. The tool combination includes hobs and cutting knives. The shaft of the hob is equipped with sensors.  The rear part is fixedly installed on the cutter head, and the rear part of the cutter is installed on the cutter head through a base with a hydraulic expansion device. The base can move back and forth along the shield 
machine axis, but the shield 
machine tool is limited  The front cutterhead of the shield machine is an integral structure, which can only be drilled into the rock and soil by controlling the hob and cutter, and cannot accurately adjust the penetration of the shield cutterhead during construction in various strata such as soft stratum, hard stratum, and soft-hard stratum.  The 
drilling force of the surface is high, and the cost is high, and the hard formation in the soft and hard formation cannot be cut
[0006] Chinese patent CN203891774U is a five-blade PDC 
drill bit suitable for soft and hard formations, including a 
drill body and five blades protruding from the crown of the drill body, and several grooves for discharging debris are formed between the blades  , the 
drill bit drills holes by adjusting the distribution angle of the blade and the distribution of the main cutting teeth on the blade.  It cannot guarantee the stress uniformity of the main structure in soft and hard formations, and cannot be used for drilling and cutting in soft and hard formations in rock and soil.
This device is mainly aimed at the stress situation when cutting soft and hard rocks. It maintains 
constant pressure on the soft rocks that are drilled and applies air pressure to the hard rocks that are not fully cut.  The problem of real-time adjustment of the cutting force on the cutting surface of different formations such as strata, and the rapid 
discharge of chips when cutting soft and hard formations cannot be solved, especially hard formations cannot be cut, and the force uniformity of the cutting device cannot be maintained