FI87390C - Drilling procedure and drill bit apparatus - Google Patents

Description

873S0

DRILLING METHOD AND DRILLING EQUIPMENT

The invention relates to a method for carrying out drilling for soil research, according to which drilling is started by a press drilling method and then, if necessary, continued from the same hole by a drilling machine drilling-5 method.

According to known research methods, the composition of the soil can be studied in many ways. One way is to do the research by the press drilling method in case the soil is soft. Drilling with drilling primarily determines the location of the surface of 10 rocks.

The disadvantage of the above methods is that whenever the drilling method has to be changed, the equipment also has to be changed. However, the introduction of new equipment and the replacement of existing equipment 15 between studies is problematic, as the amount of work required increases considerably, even more than doubling.

Press drilling and drilling cannot be performed on the same equipment due to differences in methods. One reason for this is that water or air flushing is used in drilling, which is why the drill bit must have flushing channels. However, since rinsing is not used in press drilling, the channels are blocked during this work step, and once they are blocked, it is no longer possible to continue with 25 drill drills.

According to a known solution, a non-return valve is placed inside the drill bit, which closes the flushing channels in the drill bit during the pressing step. When drilling is started after press drilling, the flushing pressure opens the valve. However, due to the location of the valve, the operation of the drill bit is uncertain. In addition, it follows from the wear of the drill bit that the 2 87390 measurement results obtained are not comparable.

The object of the present invention is to eliminate the above-mentioned problems and to provide a new method and a new apparatus which do not have the above-mentioned drawbacks.

The method according to the invention is characterized in that drilling is started by press drilling with a drilling rig installation comprising a drill bit and a guard placed on it, that when the drilling rig meets a rock or a hard soil layer in the press drilling that press drilling is not desired or cannot be continued the drilling is stopped, and that the same drilling rig is switched to percussion drilling, whereby when the percussion drilling 15 is started, the impact force on the drilling rig breaks the guard placed on the drill so that it exits the top of the drill.

The invention combines two methods known per se, press drilling and drilling machine drilling. Drilling is started with 20 press drills so that the drill bit is covered with a disposable drill bit guard that mimics the tip of a press drill bit. Press drilling is continued until rock or a hard layer of soil is reached that press drilling is not desired or cannot be continued. When the drill is now switched to drilling, the drill bit guard is broken and drilling can be continued as drilling.

Thus, by means of the invention, it is possible to switch from press drilling directly to drilling machine drilling without the delay which would necessarily be caused by changing the equipment.

The invention also relates to a drilling rig installation for soil research, comprising a drill bit and a disposable guard placed on it, which can be removed from the top of the drill bit at a desired stage, for example so that the guard breaks when drilling. The drill bit apparatus according to the invention is characterized in that the tip of the guard to be placed on top of the drill bit is shaped to fit the press drilling, 5 and that the strength of the guard is formed so that in press drilling the guard

The invention will now be described, by way of example, with reference to the accompanying drawings, in which

Figure 1 schematically shows a vertical section of the soil and a press drilling step according to the invention. Fig. 2 corresponds to Fig. 1 and shows schematically a drilling drilling work step according to the invention.

Figure 3 schematically shows the curves obtained from the measuring sensors.

Figure 4 shows a drill bit on which a guard according to the invention is placed.

Figure 5 shows a drill bit in a drilling rig 20 without protection.

Figure 1 schematically shows a vertical section of the soil 10 and the press drilling step of the soil survey according to the invention. The figure shows an above-ground machine 20 performing press drilling. Connected to the implement 25 is a drill rod 21 which is pressed into the ground vertically, i.e. in the z-axis direction at a compression speed v, with a corresponding compression force F. The drill rod 21 is rotated at a rotational speed with a corresponding torque My. Drilling-related parameters are continuously measured 30 and the results are recorded by a recording device 30 connected to the implement. The plots of the plotter are shown in more detail in Figure 3.

In Figure 1, in the exemplary case, the top layer on the ground surface is a dry shell layer 11, under which are soft clay 12 4 87390 and silt 13. The gravel layer 14 below these is already clearly harder than the previous ones. The press drilling is performed in Fig. 1 by these so-called through the soft soil layers along the distance a using the drill bit apparatus 22 of the invention.

5 It includes the drill bit required for drilling, which is covered with a disposable guard. This structure is shown in more detail in Figure 4.

In Fig. 1, the required compressive force F in different layers of soil next to the drill rod 21 is plotted as a function of the depth z. It can be seen from the figures that the compressive force required for the dry shell layer 11 is quite high, but it is clearly lower when pressed through the clay 12. At the bridging layer 13, the compressive force varies and the compressive force required in the gravel layer 14 again increases sharply. In the example case shown in Fig. 15, the press drilling has been continued until the pressing force F reaches the limit of 30 kN. This limit is reached in the situation shown in the figure. In this case, the press drilling is stopped and the drilling is switched to drilling.

20 The strength of the disposable guard of the drill bit is dimensioned so that the guard breaks when the impact of the drilling rig is initiated. In this case, the rinsing channels of the drilling machine open and drilling can be continued as drilling of the drilling machine up to the desired depth.

Figure 2 shows a situation in which the drilling of the impact drill has been continued for a distance b without the drill bit guard. In this work step, in addition to the previous parameters, the rinsing water pressure p is also registered. This allows the soil layers 30 shown in this example, which are the gravel layer 14 and the moraine 15, to be traversed. Figure 2 has drilled into the rock to the desired depth. In this case, progress has been made e.g. through the bruise layer 17.

Figure 3 shows an example diagram 31 obtained from the plotter 30. The first on the left is the compression speed v, the unit of which is meters per minute. The next curve from the previous to the right is the modified penetration rate vf, which is a computational curve and filters the irregularities of the previous curve. The third curve from the left is the rotational speed uj, the unit of which is revolutions per minute. The fourth curve is the torque My, the unit of which is Nm. The torque value is obtained from the hydraulic pressures and is used to measure the drill rod casing friction. The fifth curve is the compressive force F, the unit of which is 10 kN. The sixth curve is the rinsing water pressure pw, the unit of which is a bar. The seventh curve is the amount of rinsing water Qw, the unit of which is liters per minute. The remaining two right-hand curves B and Krel are computational auxiliary parameters used to determine soil species characteristics. It is also possible to select a point on the plotter curves where the transition from press drilling to drilling machine drilling is made.

Fig. 4 shows a drill bit apparatus 22 according to the invention, comprising a drill bit 23 used in drilling machine drilling and a disposable protective piece 24 placed thereon. The protective piece 24 is made of a material that is broken by the impact force of the drilling machine drilling. Such materials are, for example, plastic or metal, preferably light metal. To provide good penetration properties, the tip of the shield 24 is conical. The shape mainly corresponds to the shape of known press drilling tips. In the example of Figure 4, the angle α of the cone is 60 °.

The guard 24 of Figure 4 is configured to remain well in place during press drilling. The edges 25 can be shaped to press against the drill bit 23. The guard piece 24 can also be provided with notches suitable for the grooves 26 of the drill bit 23, which prevent the guard member 24 from rotating relative to the drill bit 23.

Figure 5 shows the drill bit assembly 22 of Figure 4 after the disposable guard 24 has broken and exited the top of the drill bit 23. What remains is a conventional drill bit, with which drilling is continued as drilling machine drilling after flushing has begun.

5 Method description;

The drilling to be developed is a combination of two existing drilling methods, the press drilling method and the drilling machine drilling method. The combined drilling method provides a new bottom survey method that can effectively determine the structure and geotechnical properties of the soil.

The combination of said methods is made possible by a new conical tip according to the invention. The tip is designed taking into account the international standard recommendation. Essential to the tip according to the invention is that during the press drilling section the tip prevents the penetration of soils into the rinsing channels, and that when performing press drilling with the tip according to the invention, sufficient comparability is achieved compared to conventional press drilling.

To enable more accurate and versatile informative registration, automatic registration equipment is used, which can register up to eight information channels simultaneously if necessary.

25 Equipment to be used;

In order to implement the drilling method according to the invention, a drilling machine is used in the drilling equipment, the power of which is dimensioned so that it achieves sufficient capacity even in difficult conditions. In this case, the problems caused by the inefficiency of the current equipment available can be eliminated. On the other hand, however, the method according to the invention can also be utilized with the devices in use. Limitations can be caused by equipment inefficiencies.

5 Geotars that are well-suited for drilling can be used as drill rods without problematic couplings.

As the recording equipment, some existing equipment can be used, such as a Geoprintter, with 10 six channels capable of registering six different pieces of information as a function of depth. The information to be recorded is usually as follows: - borehole depth - drill rod penetration speed 15 - drill rod rotation speed - drill rod torque - drill rod compression force - rinsing water pressure

The registered data can be used to determine the design parameters required for geotechnical design. The parameters can also be determined automatically from the collected data using a computer, in which case the designer has immediate access to the preliminary parameters.

Tv example: 25 Drilling begins after a possible dry shell or backfill layer has passed as a press drilling. At this stage, a disposable conical tip according to the invention is mounted on the tip of the drill bit. The drill rods are pressed into the ground, for example at a constant speed of 3 m / min, while rotating 30 drill rods at a rotation speed of 25 r / min. No rinsing is used during press drilling. That would not be possible, as the conical tip covers the rinsing holes of the tip. During press drilling, the automatic recording device stores all parameters except those related to rinsing, such as the pressure of the rinsing water.

5 Upon reaching, the impermeable layer is transferred to the impact drill machine drilling. In this case, the press-tin drill bit tip on top of the drill bit is crushed. In this case, rinsing and registration of rinsing parameters are also started.

After the drilling has progressed to the rock surface, the 10 drillings can be continued to the desired depth. During rock drilling, the same parameters are registered and from them, for example, the rupture of the rock and the location of the fractures can be deduced.

Benefits to be achieved: 15 The new press drilling will bring significant advantages in both the research and design sectors compared to current methods. Among other things, the determination of the geotechnical properties of the soil layers by drilling becomes much more precise as a result of the more advanced drilling method and the 20 automatic registrations used.

A significant effect on costs is that in many cases the new drilling method and the equipment according to the invention provide sufficient information about the soil and bedrock in a single drilling. Therefore, it is no longer necessary to perform preliminary and final baseline studies separately.

The speed, affordability and accuracy achieved with the method and equipment according to the invention make it possible to optimize costs in a completely new way. At the same time, a significant improvement in the quality of the results will also be achieved, which in turn is common to the research and design sectors

9 8 7 o S O

advantage.

It will be apparent to those skilled in the art that various embodiments of the invention may vary within the scope of the claims set forth below.

Claims (7)

A method for drilling for soil exploration (10), wherein the drilling process is started with a pressure drilling method and then continued in the same hole if necessary with a percussion drilling method, characterized in that - drilling is started with a drill bit device (22) comprising a drill bit device (22). drill bit (23) and a protective bit (24) placed on this, - when the pressure drilling device during the pressure drilling bumps on bedrock or a hard soil layer (14), that pressure drilling is no longer desired or can be continued, the pressure drilling is completed, - and that with the same drill bit device is transferred to percussion drilling, whereby at the start of the percussion drilling a shock force directed against the drill bit device, the protective bit placed on the drill bit breaks, so that the drill bit is exposed. Method according to claim 1, characterized in that drilling is continued after •; The pressure drill as percussion drilling without lifting the drill bit assembly (22) therebetween. Method according to claim 1 or above 2, characterized in that, after the pressure drilling, the percussion drilling can be continued to the desired depth (b). 4. Ground drill bit assembly (22) comprising a drill bit (23) and a disposable single-bit guard piece (24) that can be removed from the drill bit at the desired stage, for example, such that the protective bit is broken when the percussion drill is started , characterized in that - the tip of the protective bit (24) to be placed on the drill bit (23) is designed so that it is suitable for pressure drilling, and - that the pour strength of the protective piece is made such that the protective strength of the protective bit during the drilling is sufficient, but the impact force at the start of the percussion drill breaks the protective bit. 5. The drill bit assembly according to claim 4, 5, characterized in that the bit (24) of the drill bit (23) is shaped so as to mimic the point of the press drill bit. 6. A drill bit assembly according to claim 5, characterized in that the tip of the protective bit (24) of the drill bit (23) which mimics the tip of the press drill is a cone whose angle (a) is 60 °. Drill bit assembly according to claim 4, 5 or 6, characterized in that the protective bit (24) of the drill bit (23) suitable for press drilling is made of plastic or metal, preferably light metal.