ASSESSMENT OF LOCATIONS ALONG THE PROPOSED HS2 ROUTES THAT ARE LIKELY TO EXPERIENCE GROUND VIBRATION BOOM FROM HIGH-SPEED TRAINS

1 INTRODUCTION
The demand for high speed rail transportation has signicantly increased over the last decade. This
way of transportation is convenient and environmentally friendly. However, high train speeds bring
into consideration some new environmental problems that were unknown for conventional trains.
One of the most important is a dramatic increase in the level of railway-generated ground vibrations
that can occur when the train speed exceeds the velocity of Rayleigh surface waves in the
supporting ground, This phenomenon is known as ☁ground vibration boom☁ (GVB), and it was first
predicted theoretically in the papers☝. Soon after that, it was observed experimentally on the new
high-speed railway line in Sweden☁, Further theoretical investigations of GVB have been carried out
in the papers☜. Note that the phenomenon of ground vibration boom from high♥speed trains is
similar to the well-known phenomenon of ☁sonic boom☂ from supersonic aircraft that occurs when the
speed of aircraft exceeds the velocity of sound in air. The essential difference though is in the fact
that, whereas sound velocity in air is roughly the same in all locations above earth surface, the
Rayleigh wave velocity is different in different locations, depending on geological properties of the
ground. in some locations, where the ground is soft and marshy, the Rayleigh wave velocity can be
very low. Such ☁sensitive' locations are most likely to experience ground vibration boom from
operating high-speed trains.
In the majority of geographical areas ground vibration boom is not a problem within high speed rail
networks as, although the technological development of high speed trains now has them reaching
service speeds surpassing 320km/h. Rayleigh waves usually travel at much higher velocities than
this. However, in softer ground the propagation velocity of Rayleigh waves can be severely
reduced, resulting in a higher number of occurrences of ground vibration boom along the route.
The present paper describes the results of the preliminary assessment of the proposed H32 route
from the point of view-of possible occurrence of the phenomenon of ground vibration boom. The
analysis is based on the available geological information about the soil composition along the
proposed HSZ route and on the available information about the expected train speeds along the
route, including areas of train acceleration and deceleration after departure from or before approach
to railway terminals. Rayleigh wave velocities have been calculated for all distinctive sites along the
route using the geological data and compared with the expected train speeds at the relevant
locations. Using this method. several sensitive locations have been identied where ground
vibration boom is likely to oocure if no mitigation is applied. The expected levels of ground vibration
boom have been estimated using the earlier developed theorys☁ 7☁ Some vibration reduction
techniques are suggested to reduce effects of ground vibration boom on local residents and
busineses.
2 INFLUENCE OF GEOPHYSICAL PROPERTIESS OF SOILS
As was mentioned above, ground vibration boom occurs when the speed of a train exceeds the
velocity of Rayleigh waves. Therefore, it is necessary to study the effects of geophysical properties