WW

UP THE CAUSE OF THE DESEHUED
GHDUND SETTLEMENT

 

T. EDHCLUSIGNS

After reviewing the facts and with hindsight 'u'iein' the fella-wing ccinclusicins can he reached:

At no time. prier tn the sin-inhale there were ant,r signs at gmund less in the instru mentatien.
Furthermore. at ne point in time did the eetensnmeter cIr ether gentechnical

instru mentaticin clata indicate that a sinkhele was eminent.

At nn time prior tn the were there ant-I Ite'l.r TBM parameters as indicated in the

Tunnel Plan in the red level.

Ba5ecl en the infemtatinn gathered tram the TBM parameters and the instrumentaticln, it"s
net pessible tn determine unequitrncally the reaspn fer the grciund settlement- The 
petential reascins are a preexisting amid, a gre und less in the face at the TBM er a

ccln'lbinatin-n pf bath.

The Design includes several measures preteet the integrity, which have been
ca nsidered suf?cient be WSDCIT- The integrity ef the has not been eempremised at antr

time.

Stepping the TEIM at its cerrent lecatien is net recent rnenclecl and increases the risk at
creating additienai sinkheies. There is a seheti uleel step at the TBh-l just hefere the at
the only 25-13 It EIWEW them the current TIE-M static: n- In ardEr th iclenti?.r with same
certainty the cause at the sinithcileJ it is tn ccintinue the excavatie-n up tn the
SHS and increase the freq at the readings at the instrumentatinn and TEll'u'l parameters

defined in the Tunneling Work Plan and Tunneling Actinn Plan.