Recently, TYHEN Foundation Construction mobilized four KR125A and one KR220C rotary drilling rig in Nantong sixth Construction company’s rundown areas reconstruction project. The geological conditions of the site are mainly backfill soil, clay, strongly weathered and moderately weathered limestone, and karst caves of different sizes. The depth of the pile is 13~36m, and the diameter is 600mm. The bearing layer of the pile body is moderately weathered limestone, and there should be no karst cave 10 meters below the pile, otherwise, it is necessary to pass through the karst cave to reach the ideal bearing layer. The stratum is complicated and the construction is extremely difficult, especially having to go through the karst cave, back-filled layer to re-entering into the rock. Rotary drilling rig bored into the rock again need to ensure the verticality of the pile, so the rig stability and reliability requirements are very high, with the operator's skilled judgment. At the same time, with the full support of Tyhen experts, the bore holes were smoothly drilled wining good praise from the owner and the main contractor.The total weight of TYSIM KR125A rotary drilling rig is 35 tons. The construction diameter ranges from 400mm~1500mm with a construction height of 15 meters.  KR125A can be transported in one load together with the Kelly bar. The automatic folding of the mast function can reduce the transport height and to eliminate the need to disassembly and assembly during transportation. The imported original speed reducer and motor enable the rig to have good climbing performance.  At the same time, 125 KN.m of power head torque is also able to cope with most of the pebbles, gravel and other geological conditions.  The original Cummins engine with strong power is selected, and the electronic control system and hydraulic system of TYSIM core technology are used to give a full play to its working ability. The whole series of products have passed the GB certification and the CE certification of the European Union. The better dynamic and static stability design ensures the safety of construction.TYHEN foundation construction co., ltd considers “service” as its core value, and utilizes such attitude to provide clients with an “Eight in One” service in terms of selling, leasing, construction, trade-in, re-manufacturing, service, operator supply & training, and consulting & promotion of drilling methods. The company has over 60 small and medium sized piling rigs. With the maintenance service and delivery service of piling rig provided by dozens pilling manufacturer, TYSIM has established a joint maintenance base that employs a technical and professional maintenance team which has years of experience in machinery servicing to provide clients with professional construction advices and methodologies. After five years of experience, commitment, cooperating with customers and also independent construction works, our small rotary rigs had participated in relatively modern constructions such as dam-reinforcement, underground pipe gallery, and over-water construction, which ultimately contributed towards the domestic promotion of the utilization of small rotary rigs. At the same time, Tyhen is committed to creating a leading professional piling service platform at home and abroad.