SU1341602A1 - Method of exciting seismic oscillations - Google Patents

Abstract

The invention relates to seismic engineering and is intended to initiate seismic vibrations in the ground. The purpose of the invention is to increase seismic efficiency by reducing energy loss. The method allows to prevent the movement of the soil mass under the base plate (OD) of the vibration source. When a vibration source is operating as a result of cyclic loading, there is a loss of strength in the volume of soil beneath the source OP, break lines (slip lines) appear, the velocity field along which the attached ground mass moves, and the seismic energy transmission conditions deteriorate. Introducing the grating to a depth of H, above the level at which the boundary of the slip line passes, reduces the energy loss of a seismic wave as it propagates from the OP deep into the Earth. 2 Il. from $ (L 00 4 O5 O N :)

Description

H

This invention relates to seismic exploration of minerals, in particular oil and gas. ,

The purpose of the invention is to increase seismic efficiency.

Fig. 1 schematically shows a device implementing the proposed method; in FIG. 2, view A in FIG.

The device for implementing the proposed method comprises an electronic control system 1 and a vibration exciter comprising a hydraulic cylinder 2 driven by an electro-hydraulic amplifier 3. The vibration driver consists of a reactive mass 4 and an active mass made in the form of a rod 5 ending with a base plate 6, Fp, installed on the ground.

On the base plate 6, a reinforcing lattice 7 with an area F, is mounted (in this case, welded), made of vertical longitudinal 8 and transverse 9 plates welded to the ends. The installation of the grill 7 can be done by gradually crushing it onto it with the plate 6 followed by hanging the vehicle for burial. Here, the ratio F.7 / F is fulfilled. The magnitude of the deepening of the lattice H is selected from the following assumptions. This value should not be less than the depth at which the slip line appears under the base plate 6, and the ground is divided into moving and stationary parts.

N2 (-f} (2 - /) /

and TG 10 + 2 corner j 1

where Tj () is the conditional radius

base plate;

J (Vj / Vp) is the ratio of the velocities of the transverse V and longitudinal V waves.

The method is carried out as follows.

When the source is operating, the electronic control system 1 generates a periodic control (its signal arriving at the input of the electro-hydraulic amplifier 3, which, in accordance with this signal, supplies fluid under pressure alternately to the upper, then to the lower plane, hyd

cylinder 2. The resulting force action is applied on one side through the rod 5 to the base plate 6, exciting a seismic wave in the ground, and on the other hand to the reactive mass 4, causing it to reciprocate near the middle position. Q Base plate 6, the excitation of a seismic wave, which is a vibration, compression and shear variation, does not cause a vibratory source of movement of this part of the ground and the occurrence of slip lines in the area of the ground reinforced by the grille 7. The soil particles under the slab 6 in the area reinforced with the lattice 7, presumably weakly coupled Q structures are strengthened, and the energy of the source is not spent on increasing the kinetic energy of the soil particles, but is converted into the potential energy of the elastic interaction. This increases the proportion of the energy transmitted by the source to the ground in the form of seismic waves, which leads to an increase in the seismic efficiency of the vibrational source.

Claims (1)

Invention Formula A method for exciting seismic vibrations using a vibrating seismic source placed on the ground with known longitudinal VP velocities and transverse v seismic waves and incorporating an actuator rigidly connected to the base plate F in contact with the ground, which are embedded below it embedded in the ground vertical elements, characterized in that, in order to increase seismic efficiency by reducing energy losses, vertical elements are mounted in the form of space lattice area of F 7 / F, and the height of the vertical five 45 50 H7, liK 55 items  12 (L f 10 + 2fi where r is the conditional radius of the reference plates, g (f /); y (Vj / Vj is the ratio of the velocities of the transverse and longitudinal waves. I 2 5 pi / e. R OOOOOSE1 oooooh OOOOOQI ooooshe Editor E. Kopcha Compiled by A. Aleshin Tehred L. Serdyukova Proofreader M. Pojo Order 4434/51 Circulation 730 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow Zh-35, Raushsk nab., d.4 / 5 .., ...-.-- -.- - -. --- - ---- "-------- - - - - Production and printing company, Uzhgorod, Projecto st., 4 Ace1 oo 7 -5 Fie.2