Analysis of cement-treated soil slab for deep excavation support – a rational approach

Abstract

In this study an effective stress model for cement-treated soil is employed to carry out a systematic study on cement-treated soil slab used to control the wall displacement in excavations with thick, soft clay layers. Deterministic analyses were first conducted to assess the drainage state of the treated soil slab. These indicate that, under timescales which are representative of those in actual construction, cement-treated soil slab conditions may range from nearly undrained to drained. Random finite-element analyses also show that the global undrained and drained behaviour of the treated soil slab differ significantly. Undrained loading leads to a rapid rise in stress with strain to a peak strength with subsequent softening. Drained behaviour, on the other hand, leads to a more compliant response, which suggests that the main issue in the drained condition is likely to be large displacement, rather than complete collapse. A rational design framework for cement-treated soil slab is proposed, which explicitly considers the distribution in global behaviours of the treated soil slab. This differs from current limit state approaches which are largely based on statistical properties of the input data, such as the unconfined compressive strength of sampled cores.

An efficient transient‐state algorithm for evaluation of leakage through defective cutoff walls

“…3,41 The random inclinations lead to the decoupling of adjacent jet-grouted column members, and this effect becomes worse with increasing depth. It can be described by two angles, 16,17,[45][46][47][48][49] that is, the azimuth (α) and the inclination angle (β), Figure 2A, which can be simulated using random variables. Moreover, the column diameter has been simulated as a one-dimensional random process.…”

Site Measurement and Study of Vertical Freezing Wall Temperatures of a Large‐Diameter Shield Tunnel

“…e former leads to the formation of a continuous wall with high strength and low permeability through cement hydration and a pozzolanic reaction within a certain curing time [19]. However, deep-mixed or jetgrouted mixing piles usually have random untreated areas due to inevitable error though they were installed with due discretion [20][21][22][23][24][25][26]. ese untreated areas have an adverse effect on the strength and water-tightness of the treated ground [24,25,[27][28][29].…”

“…However, deep-mixed or jetgrouted mixing piles usually have random untreated areas due to inevitable error though they were installed with due discretion [20][21][22][23][24][25][26]. ese untreated areas have an adverse effect on the strength and water-tightness of the treated ground [24,25,[27][28][29]. In the latter case, the temperature of the surrounding soil is lowered to freezing point by a supply of low-temperature-concentrated saline solution into the freezing pipe, so that the pore water of the soil is frozen, thereby temporarily improving the strength and watertightness of the soil.…”

Mathematical Models for Stress–Strain Behavior of Nano Magnesia-Cement-Reinforced Seashore Soft Soil

“…Soft soil is widely distributed in coastal areas with many defects such as large natural moisture content, excessive compression capacity, and poor bearing capacity [1][2][3]. In geotechnical engineering, deep mixing method is generally adopted to improve the strength of soil by adding cement to the soil [4][5][6][7][8]. The soft soil is reinforced to impart higher strength through a series of reactions between raw materials and curing agent [9][10][11][12][13][14][15][16].…”