## 1 Introduction
Both Types \(B\) and \(C\) increase the bonding between the grout and ground compared to Type \(A\); however, higher pressure (>1 MPa) is difficult to apply because of the geotechnical uncertainties (e.g., potential hydro-fracturing of the ground or leakage along the casing, Table 1[12,13]). To handle these issues, a Type \(D\) method uses a packer to constrain the grouting and enhance the bonding process [14]. Primary grouting is first introduced into the borehole, and a high level of pressure (2-8 MPa) is applied with the presence of the packer. Figure 1: Uplifting mechanism of foundation systems adjacent to a river channel. (**a**) Underground construction inducing seepage into the construction space, and (**b**) buoyancy of the structure is induced after backfilling due to recovery of ground water. This mechanism causes an uplifting force to act on the foundations. [PERSON] (1986) suggested that pressure grouting might be an effective countermeasure for a pervious tunnel with many fractures ([PERSON] and [PERSON] (2006) observed that the maximum settlement of the crown of the tunnel was reduced as the pressure of the grouting was increased ([PERSON] and [PERSON] (2006). In addition, pressure-grouted soil nailing can be effectively applied to completely decomposed granite fill ([PERSON] and [PERSON] (2006). Therefore, the pressure grouted micropile is an attractive and reasonable option for overcoming irregularities and weaknesses in the fractured zone. The packability of the packer is the key factor in determining the performance of the micropile. The packer is typically a sack-shaped geotextile consisting of expanded polytetrafluoroethylene (ePTFE). This packer is manually fixed at the desired location and tightened by wires. However, due to manual packing, grouting is susceptible to leaking from inside the borehole ([PERSON] and [PERSON] (2006); [PERSON] (2006). Moreover, during the boring of the hole, water and soils inside of the borehole are mixed, and a slime (slurry) is produced. The slime decreases the bonding stress between the reinforcing bar-grout- soils and increases the settlement of the foundation system ([PERSON] and [PERSON] (2006); [PERSON] (2006). It is almost impossible to address the slime problem using existing packers. A newly devised rubber packer was introduced in this study to overcome the issues on the conventional packer ([PERSON] and [PERSON] (2006). The rubber packer can induce higher packability onto the borehole due to its flexibility of rubber than the geotextile packer. The rubber packer is possible to reuse after use. Moreover, the rubber packer has a nozzle that can drain the slime inside the borehole leading better capacity of micropiles. Despite the importance of the packer's packability, the pressure-grouted micropile with packer is yet well-evaluated. Even research on the conventional (geotextile) packer are limited for micropile either lab or field. Therefore, in this study, tension load and creep tests were conducted to evaluate and compare the performance of micropiles installed by different methods, such as gravitational grouting and pressure grouting using geotextile and rubber packers.