Layered Grouting Technology Based on a Comprehensive Water-to-Cement Ratio for the Overlying Loess Stratum of Urban Shallow Tunnels

Table 4

Compressive strength variation amplitude of loess before and after grouting.

Test number	T-1	T-2	T-3	T-4	T-5	T-6	T-7	T-8	T-9
	980	1645	2112	2308	1250	1023	1862	1392	1193
	182.3	152.4	122.8	175	134.6	218.6	145.3	261.2	203.3
Percent increase (%)	438	979	1620	1219	829	368	1181	433	487