The present invention relates to a large diameter sampler. More particularly, the present invention relates to a large diameter sampler capable of gathering an undisturbed sample in a cohesive soil or a sandy soil for examining a subsoil, a soil, a groundwater level, an internal force of a ground and a barrier situation within a plateau.
Due to rapid expansion of industry and development, civil engineering, construction, and building of facilities typically cannot be carried out on a favorably conditioned site.
That is, construction occurs in typically unfavorable places, such as a seaside, a mountainous area, and sanitary landfills, which have typically been excluded in past
Ground information and analysis through accurate ground investigation is required to ensure safe and economical designs, execution of a structure, and for repairing and maintaining of an established structure.
The ground investigation is aimed at providing basic materials, such as ground characteristics, soil conditions, and an amount of ground settlement calculation.
When designing a structure, it is important to regulate ground settlement caused by a structural load within a permitted level, whereby the load given to a foundation may not exceed the allowable bearing capacity. Therefore, all information which may affect structural safety and calculation of ground settlement may be acquired through a ground investigation.
Preferably, ground investigation is carried out delicately, before construction to determine structural requirements, foundation requirements, suitable construction methods, and suitable building materials. If the ground investigation is delayed, a fixed construction period may prevent delicate investigation of the ground, thereby making it difficult to find an economical solution.
Ground investigation typically costs about 1xcx9c2% of the total cost of construction, however, significant cost can be avoided if prevention of damage to the construction as a whole is prevented.
In advanced countries, a good deal of investment and research is being performed to invent a sampler which gathers an undisturbed sample in a soft foundation without changing soil parameters. Research results indicate that a sample gathered by a large diameter LAVAL sampler made by LAVAL University, in Canada, has little disturbance when compared to that of a Japanese sample gathered by a piston sampler.
However, in a domestic soft foundation site, a water pressure piston sampler is typically used to gather an undisturbed sample while a sandy soil is typically not gathered yet.
It is, therefore, an object of the present invention to provide a large diameter sampler capable of gathering an undisturbed sample in both a cohesive soil as well as a sandy soil for more accurately acquiring a soil parameter which is needed for the foundation design of a structure.
Another object of the present invention is to provide a large diameter sampler capable of gathering an undisturbed sample while lifting an un-cohesive sample up to the ground without spilling by equipping a cutter with both a cutting function and a sample spilling interception function within a sampling tube.
In accordance with an aspect of the present invention, a large diameter sampler is provided for gathering an undisturbed sample. The large diameter sampler includes an outer tube having a bit on a bottom portion thereof for excavating a ground, wherein the outer tube is rotated by applying an external power thereto for penetrating the tube into the ground. Additionally, a means for protecting a sample from a disturbance is provided and is generated by a rotating excavation of the bit, wherein the protecting means is located the bottom portion of the outer tube. The protecting means is disposed internally in the tube, and is penetrated into the ground by weight. A sampling tube for locating the sample pulled-out by weight of the protecting means, and a cutting means for sheltering a bottom portion of the sampling tube for protecting spilling of the gathered sample are also included, wherein the cutting means is equipped within the protecting means for cutting the sample pulled-out by the sample protecting means. Further, a means for lifting the sampling tube and the protecting means is provided, whereby the means of lifting is operable to apply a lifting force from an operating device which is located on the earth. In addition, an outer rod connects the outer tube and a boring device on the earth.