Fig.1

Technical route"

Table 1

Basic properties of silty soils， cement and fly ash"

Fig.2

Particle distribution size diagram of silty sand excavated in Jinan"

Table 2

Mix ratio of tests"

Table 3

Mix ratio of mechanical tests"

Fig.3

Variation of fluidity with the ratio of ash to water and water to solid ratio"

Fig.4

Effect of fly ash content on the fluidity of CLSM in each ratio"

Fig. 5

CLSM compressive strength of fly ash"

Fig.6

Relationship between CLSM compressive strength of fly ash"

Fig.7

28 d compressive strength with CBR and resilience modulus fit straight line"

Fig.8

Compression modulus of different materials"

Fig.9

Compression deformation of different materials"

Fig.10

Compressive strength and compressive strength loss rate after wet and dry cycles"

Fig.11

Mass and mass loss rate after wet and dry cycles"

Fig.12

Modulus of materials before and after wet-dry cycles"

Fig.13

Deformation before and after wet-dry cycles"

Table 4

Multifactor variance analysis"

Fig.14

Interaction of three factors"

Fig.15

Field backfill test section"

Fig.16

Detection of subgrade reaction modulus"

Table 5

Field test section test data and Significance test （α=0.05）"

Fig.17

Field position and data acquisition of sensors"

Fig.18

Short-term monitoring of the upper layer of the backfill area after construction（10 days）"

Fig.19

Long-term monitoring of the upper layer of the backfill area after construction（250 days）"

Table 6

Field construction cost calculation"