Field Test on Deformation Characteristics of Pile-Supported Reinforced Embankment in Soft Soil Foundation

Abstract

In this work, the settlement deformation of the soft-soil subgrade and the deformation law of the geogrid were studied based on field tests carried out on the pile-supported reinforced embankment of the Rongwu Expressway in the Xiong’an New Area. The settlement and deformation law of the reinforcement area and the underlying layer of the pile-supported reinforced embankment, the settlement law of the transverse and longitudinal sections of the subgrade, and the deformation law of the bidirectional geogrid were analyzed. The results show that reducing the pile spacing and embankment height can effectively reduce the foundation settlement. The change in the pile spacing mainly affected the settlement in the reinforcement area, while the embankment height mainly affected the substratum settlement; the differential settlement in the subgrade cross-section was mainly caused by the settlement in the reinforcement area. The settlement at the center of the subgrade was obviously higher than that at the shoulder. In terms of the geogrid deformation law of the subgrade cross-section, the geogrid deformation at the center line of the subgrade was the largest. With the increase in the distance from the center line, the geogrid deformation gradually decreased. In terms of the deformation law of the biaxial geogrid, the tensile deformation of the geogrid in the center of two piles was greater than that in the center of four piles. The transverse tensile deformation of the geogrid was greater than the longitudinal tensile deformation. The tensile stress of the reinforced materials was calculated according to four specifications, and the applicability of various methods was evaluated.

Review of Sensor-Based Subgrade Distress Identifications

“…Ground-penetrating radar (GPR) [22][23][24][25][26] Total station [27][28][29][30][31] InSAR [32][33][34][35][36] Distributed optical fiber [37][38][39][40][41] Subgrade frost heaving Ground-penetrating radar (GPR) [42][43][44][45] Multi-sensor embedding [46][47][48][49][50] Weak subgrade Falling weight deflectometer (FWD) [51][52][53][54][55][56]…”

“…Caolin Qing et al [33] constructed a single-mode settlement curve of subgrade settlement based on the total station for the construction section of the frozen soil layer. Wang Xin et al [34] analyzed the settlement and deformation laws of the reinforced area and the lower layer of the pile-supported reinforced embankment, as well as the settlement laws of the transverse and longitudinal sections of the subgrade according to the subgrade data obtained by the total station. Zhou Shunhua et al [35], given subgrade settlement distresses in soft soil areas with high compressibility and low permeability, used the total station to collect road section data and introduced the settlement evolution and settlement control effects of different treatment methods.…”

Evaluation of Differential Settlement of Subgrade for Highway-Widening Projects

“…Through numerical simulation, the influence of widening the plateau subgrade on the final settlement, horizontal displacement, and surface transverse displacement were analyzed [18]. The development of settlement [19], horizontal displacement, and pore water pressure during highway widening [20] were also analyzed by a centrifuge model test [21] and numerical analysis. Han et al [8] established a two-dimensional model of subgrade widening based on FLAC 3D and verified it with engineering examples.…”

Accumulative Strain of Sand-Containing Soft Soil Reinforced by Cement and Sodium Silicate under Traffic Loading

“…It is common knowledge that the global climate is getting warmer rapidly and the land resources are becoming scarce quickly [1]. As a result, a large number of infrastructures such as expressways and high-speed railways have no choice but to build in soft soil regions [2]. In addition, it is universally known that soft soil is widely distributed around the world [3,4].…”

“…In order to solve the problem of soft soil reinforcement, a series of methods including chemical stabilization reinforcement and physical stabilization reinforcement have been conducted in geotechnical engineering [9][10][11]. For physical stabilization reinforcement, the most commonly used materials are: (1) cotton and hemp products such as cotton fiber [12], coir fibers [13], straw fibers [14], sisal fibers [15]; (2) geotextiles such as geogrid [16]; and (3) various kinds of fiber such as polypropylene fiber [17], glass fiber [18], basalt fiber [19], and steel fiber [20]. For chemical stabilization reinforcement, the most commonly used materials are cement [21][22][23], lime [24], and fly ash [25].…”